Advanced Higher Advanced Higher BiologyBiology

Environmental Biology UnitEnvironmental Biology Unit

Anderson High SchoolAnderson High SchoolCRCR

Environmental BiologyEnvironmental Biology

The Environment and its ecosystems have The Environment and its ecosystems have political, economic and ethical dimensions political, economic and ethical dimensions due to their impact on the human speciesdue to their impact on the human species

This unit will help you to understand the This unit will help you to understand the interactions between organisms and their interactions between organisms and their environment, and the human influence on environment, and the human influence on the world around usthe world around us

Advanced Higher AssessmentAdvanced Higher Assessment

Environmental Biology is a 40 hour UnitEnvironmental Biology is a 40 hour Unit Involves lectures, tutorials, discussions, Involves lectures, tutorials, discussions,

practical work, presentations and practical work, presentations and assessments all to help with the learning assessments all to help with the learning process and in preparation for University process and in preparation for University LifeLife

NAB (sit in March after Prelims)NAB (sit in March after Prelims) Assessment – 2 ½ Hours (Feb & May)Assessment – 2 ½ Hours (Feb & May)

Environmental BiologyEnvironmental Biology

10 Topics10 Topics 1 Energy Fixation1 Energy Fixation2 Circulation of Nutrients2 Circulation of Nutrients3 Biotic Interactions3 Biotic Interactions4 Symbiotic Relationships4 Symbiotic Relationships5 Costs/Benefits of 5 Costs/Benefits of

CompetitionCompetition6 Survival Strategies6 Survival Strategies7 Succession7 Succession8 Intensive Food Production8 Intensive Food Production9 Increase in Energy Needs9 Increase in Energy Needs10 Pollution10 Pollution

1. Energy Fixation1. Energy Fixation Energy is required by all organisms for Energy is required by all organisms for

cellular activities, growth & cellular activities, growth & reproductionreproduction

The fixation of energy occurs in The fixation of energy occurs in photosynthesis by autotrophsphotosynthesis by autotrophs

Autotrophs (are producers) that Autotrophs (are producers) that change light energy into chemical change light energy into chemical energy to make organic moleculesenergy to make organic molecules

Heterotrophs (are consumers) that Heterotrophs (are consumers) that must feed on other plants or animals to must feed on other plants or animals to get a ready made supply of organic get a ready made supply of organic moleculesmolecules

Saprotrophs (are decomposers) that Saprotrophs (are decomposers) that use the organic materials from waste use the organic materials from waste and dead organisms as an energy and dead organisms as an energy sourcesource

AutotrophsAutotrophs

HeterotrophsHeterotrophs

SaprotrophsSaprotrophs

Energy CalculationsEnergy Calculations Gross Primary Productivity (GPP) is the total amount of Gross Primary Productivity (GPP) is the total amount of

light energy converted to chemical energy by autotrophslight energy converted to chemical energy by autotrophs Not all energy produced by autotrophs is available for Not all energy produced by autotrophs is available for

consumers as autotrophs use up some of the food in consumers as autotrophs use up some of the food in respiration for their own metabolic needsrespiration for their own metabolic needs

Net Primary Productivity (NPP) Net Primary Productivity (NPP) NPP= GPP – energy used in respiration.NPP= GPP – energy used in respiration. Therefore NPP is the energy available to all other Therefore NPP is the energy available to all other

organisms in an ecosystem after producer respirationorganisms in an ecosystem after producer respiration Primary productivity is measured using the biomass of Primary productivity is measured using the biomass of

vegetation added to a given area in a given time e.g. vegetation added to a given area in a given time e.g. g/m2/yearg/m2/year

Feeding RelationshipsFeeding Relationships Herbivores feed on plant material & Carnivores feed on animalsHerbivores feed on plant material & Carnivores feed on animals

Decomposers are organisms (e.g. bacteria and fungi) Decomposers are organisms (e.g. bacteria and fungi) (saprotrophs) that breakdown organic matter by secreting (saprotrophs) that breakdown organic matter by secreting digestive enzymesdigestive enzymes

Detritivores are organisms (e.g. earthworms & woodlice) that Detritivores are organisms (e.g. earthworms & woodlice) that feed on detritus (decomposing material)feed on detritus (decomposing material)

Primary consumers are herbivores that feed directly on producersPrimary consumers are herbivores that feed directly on producers

Secondary consumers are carnivores that feed on primary Secondary consumers are carnivores that feed on primary consumersconsumers

Tertiary consumers are carnivores that feed on secondary Tertiary consumers are carnivores that feed on secondary consumersconsumers

A trophic level is a feeding level present in a food chain or food A trophic level is a feeding level present in a food chain or food webweb

Energy flow in a food chain or food web is represented by arrowsEnergy flow in a food chain or food web is represented by arrows

Energy transfer is not very efficient. Only 10% of energy at one Energy transfer is not very efficient. Only 10% of energy at one trophic level is passed on to the next level trophic level is passed on to the next level

Biological PyramidsBiological Pyramids Pyramids of numbers represent the number of Pyramids of numbers represent the number of

organisms at each trophic levelorganisms at each trophic level

Pyramids of biomass represent the mass of Pyramids of biomass represent the mass of organisms at each trophic levelorganisms at each trophic level

Pyramids of productivity represent the energy Pyramids of productivity represent the energy available at each trophic levelavailable at each trophic level

In an ecosystem, productivity, biomass and numbers In an ecosystem, productivity, biomass and numbers of organisms tend to decrease at each trophic levelof organisms tend to decrease at each trophic level

The ultimate loss of energy is in the form of HEAT The ultimate loss of energy is in the form of HEAT (from respiration) (from respiration)

2. Circulation of Nutrients2. Circulation of Nutrients Decomposition is the breakdown of organic matter Decomposition is the breakdown of organic matter

with the release of inorganic nutrients into the with the release of inorganic nutrients into the surrounding soilsurrounding soil

Inorganic ions are released from decomposing Inorganic ions are released from decomposing matter in a process called mineralisationmatter in a process called mineralisation

Decomposers and Detritivores are involved in Decomposers and Detritivores are involved in decomposing organic matterdecomposing organic matter

Undecomposed material is called litterUndecomposed material is called litter

Completely decomposed matter is called humusCompletely decomposed matter is called humus

Invertebrate detritivores (e.g. worms) increase the Invertebrate detritivores (e.g. worms) increase the decomposition rate as they reduce the particle size decomposition rate as they reduce the particle size of the detritus, making it easier for the of the detritus, making it easier for the decomposers (bacteria & fungi) to break down decomposers (bacteria & fungi) to break down detritus to form humusdetritus to form humus

Decomposers are the ultimate releasers of energy Decomposers are the ultimate releasers of energy and carbon dioxide fixed in photosynthesisand carbon dioxide fixed in photosynthesis

Nutrients must be recycled for the primary Nutrients must be recycled for the primary producers to useproducers to use

Detritivores (e.g. worms)Detritivores (e.g. worms)

Decomposers (e.g. wood fungi)Decomposers (e.g. wood fungi)

Nitrogen CycleNitrogen CycleThere are 4 main stages – Fixation, Nitrification, Denitrification and AmmonificationThere are 4 main stages – Fixation, Nitrification, Denitrification and Ammonification

1.1. Fixation is when Atmospheric Nitrogen is converted to AmmoniaFixation is when Atmospheric Nitrogen is converted to Ammonia Free living cyanobacteria in the soil fix nitrogenFree living cyanobacteria in the soil fix nitrogen Rhizobium bacteria in the root nodules of legumes fix nitrogenRhizobium bacteria in the root nodules of legumes fix nitrogen Cyanobacteria & Rhizobium bacteria have an enzyme complex called nitrogenise which converts Cyanobacteria & Rhizobium bacteria have an enzyme complex called nitrogenise which converts

atmospheric nitrogen to ammonia with the use of ATPatmospheric nitrogen to ammonia with the use of ATP The plant (legume) and the Rhizobium bacteria produce a molecule called Legheamoglobin. This molecule The plant (legume) and the Rhizobium bacteria produce a molecule called Legheamoglobin. This molecule

binds with oxygen which is really important as nitrogen fixation is an anaerobic processbinds with oxygen which is really important as nitrogen fixation is an anaerobic process

2.2. Nitrification is when Ammonium is converted to Nitrites then to NitratesNitrification is when Ammonium is converted to Nitrites then to Nitrates Nitrosomonas and Nitrobacter bacteria carry out this processNitrosomonas and Nitrobacter bacteria carry out this process The nitrates are then used by plants to make proteins & nucleic acids (assimilation)The nitrates are then used by plants to make proteins & nucleic acids (assimilation) Nitrates can be lost by leaching and denitrifying bacteria (Pseudomonas)Nitrates can be lost by leaching and denitrifying bacteria (Pseudomonas)

3.3. Denitrification is when Nitrates are converted back to Atmospheric NitrogenDenitrification is when Nitrates are converted back to Atmospheric Nitrogen Denitrifying bacteria (Agrobacterium) are involvedDenitrifying bacteria (Agrobacterium) are involved

4.4. Ammonification is when organic nitrogen in Proteins is converted into ammonia by decomposers Ammonification is when organic nitrogen in Proteins is converted into ammonia by decomposers (bacteria & fungi)(bacteria & fungi)

Water saturation and anaerobic conditions affect the cycling of nitrogenWater saturation and anaerobic conditions affect the cycling of nitrogen

The Nitrogen CycleThe Nitrogen Cycle

The Nitrogen Cycle (again)The Nitrogen Cycle (again)

Nitrogen CycleNitrogen Cycle

Nitrogen FixationNitrogen Fixation Fixation is when Atmospheric Nitrogen is Fixation is when Atmospheric Nitrogen is

converted to Ammoniaconverted to Ammonia

Free living cyanobacteria in the soil fix Free living cyanobacteria in the soil fix nitrogennitrogen

Rhizobium bacteria in the root nodules of Rhizobium bacteria in the root nodules of legumes fix nitrogenlegumes fix nitrogen

Cyanobacteria & Rhizobium bacteria have an Cyanobacteria & Rhizobium bacteria have an enzyme complex called nitrogenise which enzyme complex called nitrogenise which converts atmospheric nitrogen to ammonia converts atmospheric nitrogen to ammonia with the use of ATPwith the use of ATP

The plant (legume) and the Rhizobium The plant (legume) and the Rhizobium bacteria produce a molecule called bacteria produce a molecule called Legheamoglobin. This molecule binds with Legheamoglobin. This molecule binds with oxygen which is really important as nitrogen oxygen which is really important as nitrogen fixation is an anaerobic process fixation is an anaerobic process

Cyanobacteria

Rhizobium

Root Nodules Clover

NitrificationNitrification Nitrification is when Nitrification is when

Ammonium is converted to Ammonium is converted to Nitrites then to NitratesNitrites then to Nitrates

Nitrosomonas and Nitrobacter Nitrosomonas and Nitrobacter bacteria carry out this processbacteria carry out this process

The nitrates are then used by The nitrates are then used by plants to make proteins & plants to make proteins & nucleic acids (assimilation)nucleic acids (assimilation)

Nitrates can be lost by Nitrates can be lost by leaching and denitrifying leaching and denitrifying bacteria (Pseudomonas)bacteria (Pseudomonas)

Nitrification

Ammonium

Nitrites

Nitrates

DenitrificationDenitrification

Denitrification is when Nitrates are Denitrification is when Nitrates are converted back to Atmospheric Nitrogenconverted back to Atmospheric Nitrogen

Denitrifying bacteria (Agrobacterium) are Denitrifying bacteria (Agrobacterium) are involved involved

NitratesNitrates Atmospheric NitrogenAtmospheric Nitrogen

Agrobacteria

AmmonificationAmmonification

Ammonification is when organic nitrogen inAmmonification is when organic nitrogen in

Proteins is converted into ammonia byProteins is converted into ammonia by

decomposers (bacteria & fungi) decomposers (bacteria & fungi)

NitrogenNitrogen AmmoniaAmmonia

Bacteria involved in Nitrogen Bacteria involved in Nitrogen CycleCycle

Nitrogen Fixation - Cyanobacteria & Rhizobium(legumes)Nitrogen Fixation - Cyanobacteria & Rhizobium(legumes)Nitrogen Nitrogen AmmoniaAmmonia

Nitrification - Nitrosomonas and NitrobacterNitrification - Nitrosomonas and NitrobacterAmmonium Ammonium Nitrites Nitrites NitratesNitrates

Denitrification – Agrobacterium & PseudomonasDenitrification – Agrobacterium & PseudomonasNitratesNitrates Atmospheric NitrogenAtmospheric Nitrogen

Ammonification – Bacteria & FungiAmmonification – Bacteria & FungiNitrogenNitrogen AmmoniaAmmonia

Phosphorus CyclePhosphorus Cycle Phosphorus CyclePhosphorus Cycle Phosphorus is added to the soil by the weathering of rocks, taken Phosphorus is added to the soil by the weathering of rocks, taken

up by primary producers and returned by decompositionup by primary producers and returned by decomposition Phosphorus is a main component of nucleic acids, phospholipids, Phosphorus is a main component of nucleic acids, phospholipids,

ATP, bones, teethATP, bones, teeth Phosphorus is organic, doesn’t have a gaseous form, so the only Phosphorus is organic, doesn’t have a gaseous form, so the only

inorganic form is phosphate inorganic form is phosphate Phosphate is a limiting factor in the productivity of aquatic Phosphate is a limiting factor in the productivity of aquatic

ecosystemsecosystems Phosphate enrichment can lead to eutrophication (algal blooms)Phosphate enrichment can lead to eutrophication (algal blooms) Eutrophication is when plant and algal growth is over stimulated in a Eutrophication is when plant and algal growth is over stimulated in a

water ecosystem. water ecosystem. Fertilisers running into water systems, added nitrogen or phosphate Fertilisers running into water systems, added nitrogen or phosphate

to lochs etc can cause this over stimulationto lochs etc can cause this over stimulation The plants and algae eventually die, which reduces the oxygen in The plants and algae eventually die, which reduces the oxygen in

the water, so fish and other organisms eventually diethe water, so fish and other organisms eventually die

Phosphorus CyclePhosphorus Cycle

3. Biotic Interactions3. Biotic Interactions BioticBiotic components of an ecosystem are living factors e.g. components of an ecosystem are living factors e.g.

predation, disease, food supply, competitionpredation, disease, food supply, competition

AbioticAbiotic components of an ecosystem are non-living factors e.g. components of an ecosystem are non-living factors e.g. temperature, light intensity, soil pH, availability of watertemperature, light intensity, soil pH, availability of water

Density dependentDensity dependent factors are factors that can regulate a factors are factors that can regulate a population. These factors increase as population size increases population. These factors increase as population size increases e.g. predation, disease, food supply, competitione.g. predation, disease, food supply, competition

Density independentDensity independent factors are factors that can regulate a factors are factors that can regulate a population. These factors are independent of population size e.g. population. These factors are independent of population size e.g. hurricanes, forest fireshurricanes, forest fires

Interspecific CompetitionInterspecific Competition is interactions between is interactions between individuals of different speciesindividuals of different species

Intraspecific CompetitionIntraspecific Competition is interactions between is interactions between individuals of the same species and is more intense that individuals of the same species and is more intense that Interspecific CompetitionInterspecific Competition

Predator/Prey interactionsPredator/Prey interactions are cyclical, but slightly out are cyclical, but slightly out of phase with each other due to the changes in predator numbers of phase with each other due to the changes in predator numbers lagging behind those of the prey (e.g. Lynx – Snowshoe Hare)lagging behind those of the prey (e.g. Lynx – Snowshoe Hare)

Predators have a role in maintaining species diversity in Predators have a role in maintaining species diversity in ecosystems by controlling the numbers of more dominant ecosystems by controlling the numbers of more dominant competitors in an ecosystem, thus allowing weaker competitors to competitors in an ecosystem, thus allowing weaker competitors to survive survive

Defence Against PredationDefence Against Predation3 Main Defences:- 3 Main Defences:-

1.1. CamouflageCamouflage Camouflage is when the organisms colouring or Camouflage is when the organisms colouring or pattern pattern allows it to merge into the background allows it to merge into the background

a) Crypsis – hiding to reduce the risk of predationa) Crypsis – hiding to reduce the risk of predationb) Disruptive Colouration – patterns on body don’t b) Disruptive Colouration – patterns on body don’t

match match outline outline

2.2. Warning ColourationWarning Colouration Warning Colouration is when organisms are brightly Warning Colouration is when organisms are brightly coloured to warn predators that they are dangerous to coloured to warn predators that they are dangerous to

eat eat

3.3. MimicryMimicry Mimicry is when an organism bears a resemblance to a Mimicry is when an organism bears a resemblance to a harmful speciesharmful species

a) Batesian mimicry is when an edible or harmless a) Batesian mimicry is when an edible or harmless species mimics species mimics a poisonous or harmful species a poisonous or harmful species

b) Mullerian mimicry is when 2 or more species have b) Mullerian mimicry is when 2 or more species have evolved to evolved to have the same or similar warning signals have the same or similar warning signals

CamouflageCamouflage

Camouflage is when the organisms colouring or pattern allows it theCamouflage is when the organisms colouring or pattern allows it themerge into the background. 2 Types:-merge into the background. 2 Types:-

a) Crypsis – hiding to reduce the risk of predation (e.g. stick insects)a) Crypsis – hiding to reduce the risk of predation (e.g. stick insects)

b) Disruptive Colouration – patterns on body don’t match outline (e.g. b) Disruptive Colouration – patterns on body don’t match outline (e.g. zebra)zebra)

Warning ColourationWarning Colouration

Warning Colouration is when organisms are Warning Colouration is when organisms are

brightly coloured to warn predators that they brightly coloured to warn predators that they

are dangerous to eat! are dangerous to eat!

e.g. yellow and black markings of waspse.g. yellow and black markings of wasps

MimicryMimicry

Mimicry is when an organismMimicry is when an organismbears a resemblance to a harmful bears a resemblance to a harmful speciesspecies

a) Batesian mimicry is when an a) Batesian mimicry is when an edible or harmless species edible or harmless species mimics a poisonous ormimics a poisonous or

harmful species (e.g. harmless harmful species (e.g. harmless robber fly has similar robber fly has similar colourings to a wasp)colourings to a wasp)

b) Mullerian mimicry is when 2 or b) Mullerian mimicry is when 2 or more species have evolved to more species have evolved to have the same orhave the same or

similar warning signals (e.g. similar warning signals (e.g. social wasps and caterpillars social wasps and caterpillars of cinnabar wasps)of cinnabar wasps)

Harmless Robber fly

Harmful wasp

Wasp Cinnabar Caterpillar

GrazingGrazing

A grazer is defined as anyA grazer is defined as anyspecies that moves from onespecies that moves from onevictim to another, feeding on victim to another, feeding on

aapart of each victim butpart of each victim butdoesn’t actually kill itdoesn’t actually kill it

Moderate grazing can Moderate grazing can increase increase

the biodiversity of speciesthe biodiversity of speciespresent as grazing reduces present as grazing reduces

thethenumber of dominant grassesnumber of dominant grassesand other plants with basaland other plants with basalmeristems, which allows meristems, which allows

weakerweakercompetitors to survivecompetitors to survive

CompetitionCompetition

Competition is when organisms require the same Competition is when organisms require the same resourceresource

Interference Competition results when two or more Interference Competition results when two or more species actually fight over resources and one species species actually fight over resources and one species prevents another species from using the resourceprevents another species from using the resource

Exploitation Competition results when two or more Exploitation Competition results when two or more species use the same resources, thus reducing the species use the same resources, thus reducing the resources available for all.resources available for all.

NicheNicheFor A’Higher the term Niche means:-For A’Higher the term Niche means:-““the feeding role that a species plays within a the feeding role that a species plays within a community”community”

A fundamental niche is the set of resources aA fundamental niche is the set of resources aspecies is capable of using if there is no species is capable of using if there is no competitioncompetition

A realised niche is the set of resourcesA realised niche is the set of resourcesactually used by the species due to actually used by the species due to competitioncompetition

Resource partitioning is the dividing up ofResource partitioning is the dividing up ofeach resource by species specialisation andeach resource by species specialisation andadaptation (e.g. different lengths of beaks in adaptation (e.g. different lengths of beaks in wading birds)wading birds)

Competitive Exclusion Principle is when twoCompetitive Exclusion Principle is when twospecies compete for the same resource, butspecies compete for the same resource, butone species will dominate and the otherone species will dominate and the otherspecies will move awayspecies will move away

Resource PartitioningResource Partitioning

Exotic SpeciesExotic Species Exotic species are species that have been introduced deliberately or Exotic species are species that have been introduced deliberately or

by accident and it may have damaging effects on native species e.g. by accident and it may have damaging effects on native species e.g. New Zealand Platyhelminth (flatworm)New Zealand Platyhelminth (flatworm)

This worm has a detrimental effect on earth worms and thus effects This worm has a detrimental effect on earth worms and thus effects soil ecosystemssoil ecosystems

4. Symbiotic Relationships4. Symbiotic Relationships

Symbiosis is the relationships between Symbiosis is the relationships between organisms of different species that show an organisms of different species that show an intimate association with each other, intimate association with each other, involving at least one species gaining a involving at least one species gaining a nutritional advantagenutritional advantage

Examples of Symbiosis areExamples of Symbiosis are

Parasitism, Commensalism, and MutulaismParasitism, Commensalism, and Mutulaism

ParasitismParasitism Parasitism is a biotic interaction which is Parasitism is a biotic interaction which is

beneficial to one species (the parasite) beneficial to one species (the parasite) and detrimental to the other species (the and detrimental to the other species (the host) e.g. tapeworm and humanshost) e.g. tapeworm and humans

An obligate parasite cannot survive An obligate parasite cannot survive without the host organismwithout the host organism

A facultative parasite can live with or A facultative parasite can live with or without the hostwithout the host

Endoparasites live within a hosts body Endoparasites live within a hosts body e.g. tapeworms, liver flukes, malarial e.g. tapeworms, liver flukes, malarial parasitesparasites

Ectoparasites live on the surface of the Ectoparasites live on the surface of the host e.g. ticks, fleas, leeches host e.g. ticks, fleas, leeches

Ectoparasite – Dog Tick

Endoparasite – human tape worm

Host-Parasite BalanceHost-Parasite Balance A balance exists between the parasite and the host so A balance exists between the parasite and the host so

that there is a relatively stable relationshipthat there is a relatively stable relationship

Parasites can be transmitted to new hosts can be by: -Parasites can be transmitted to new hosts can be by: - direct contact e.g. head lice and humans touching each otherdirect contact e.g. head lice and humans touching each other resistant stages e.g. liver fluke in snail hosts are dormant in resistant stages e.g. liver fluke in snail hosts are dormant in

water, then sheep drink water and the fluke becomes activewater, then sheep drink water and the fluke becomes active secondary hosts (vectors) e.g. mosquitoes transmit the malarial secondary hosts (vectors) e.g. mosquitoes transmit the malarial

parasiteparasite

Host-parasite specificity gives evidence of evolutionary Host-parasite specificity gives evidence of evolutionary adaptation e.g. immunityadaptation e.g. immunity

CommensalismCommensalism

Commensalism is a biotic Commensalism is a biotic interaction beneficial to interaction beneficial to one species (commensal) one species (commensal) and the other species in and the other species in unaffectedunaffected

Egrets feed on the Egrets feed on the ectoparasites on back of ectoparasites on back of elephantelephant

Clownfish feed on scraps Clownfish feed on scraps of dead prey of sea of dead prey of sea anemoneanemone

MutualismMutualism

Mutualism is a biotic Mutualism is a biotic interaction beneficial to interaction beneficial to both species. both species.

The anemone is taken to The anemone is taken to new habitats when the new habitats when the crab moves so the crab crab moves so the crab gets to new food sourcesgets to new food sources

The crab gains protection The crab gains protection from predators from the from predators from the anemones stinging cellsanemones stinging cells

5. Costs/Benefits of Interactions5. Costs/Benefits of Interactions

Competition Competition (-/-)(-/-) Predation Predation (+/-)(+/-) Parasitism Parasitism (+/-)(+/-) Commensalism Commensalism (+/0)(+/0) Mutualism Mutualism (+/+)(+/+) The health of the host and environmental factors can The health of the host and environmental factors can

change the balance of symbiotic relationshipschange the balance of symbiotic relationships Humans can manage environmental factors by the use Humans can manage environmental factors by the use

of drugs and pesticides to help improve human, animal of drugs and pesticides to help improve human, animal and plant health.and plant health.

Herbicides are used in the management of plant Herbicides are used in the management of plant competition competition

6. Survival Strategies6. Survival Strategies Regulators maintain their internal environment Regulators maintain their internal environment

regardless of the external environmentregardless of the external environment regulators have homeostatic controlregulators have homeostatic control osmoregulators can maintain a stable internal water osmoregulators can maintain a stable internal water

concentrationsconcentrations homeotherms can maintain a stable internal homeotherms can maintain a stable internal

temperatetemperate Examples are mammals, insects & birdsExamples are mammals, insects & birds

Conformers cannot maintain their internal Conformers cannot maintain their internal environmentenvironment

conformers do not have homeostatic controlconformers do not have homeostatic control osmoconformers are isotonic to their surroundingsosmoconformers are isotonic to their surroundings poikilotherms internal temperature varies with the poikilotherms internal temperature varies with the

external environmentexternal environment Examples are snakes, lizards and marine fishExamples are snakes, lizards and marine fish

Regulators can occupy a wide range of habitats Regulators can occupy a wide range of habitats due to homeostatic mechanisms but conformers due to homeostatic mechanisms but conformers have a restricted habitat occupation have a restricted habitat occupation

DormancyDormancy Dormancy is a way that many organisms can resist or Dormancy is a way that many organisms can resist or

tolerate environmental conditionstolerate environmental conditions

Predictive dormancy occurs before the adverse Predictive dormancy occurs before the adverse conditions. It is triggered by environmental conditions conditions. It is triggered by environmental conditions e.g. decreasing temperature or photoperiod (and is e.g. decreasing temperature or photoperiod (and is largely under genetic control)largely under genetic control)

Consequential dormancy occurs immediately as a direct Consequential dormancy occurs immediately as a direct result of changing environmental conditionsresult of changing environmental conditions

Different forms of dormancy include:- resting spores, Different forms of dormancy include:- resting spores, diapause, hibernation & aestivation diapause, hibernation & aestivation

Types of DormancyTypes of Dormancy Resting spores – dormancy in Resting spores – dormancy in

seeds. A hard case surrounds the seeds. A hard case surrounds the dehydrated seed or spore until dehydrated seed or spore until conditions are beneficial (e.g. conditions are beneficial (e.g. warmer temperatures)warmer temperatures)

Diapause – dormancy in insects Diapause – dormancy in insects and deer. Insects won’t develop and deer. Insects won’t develop until better conditions in spring until better conditions in spring and deer mate at a particular time and deer mate at a particular time so the young are born in spring.so the young are born in spring.

Hibernation – bears, squirrels. Hibernation – bears, squirrels. Inactivity time used to escape cold Inactivity time used to escape cold weather conditions and scarce weather conditions and scarce food suppliesfood supplies

Aestivation – inactivity time Aestivation – inactivity time associated with hot, dry periods. associated with hot, dry periods. Organism remains in a state of Organism remains in a state of torpor with a reduced metabolic torpor with a reduced metabolic rate e.g. desert frogs & lungfishrate e.g. desert frogs & lungfish

7. Succession7. Succession Ecological succession is the name given to a repeatable Ecological succession is the name given to a repeatable

series of changes in the types of species which occupy a series of changes in the types of species which occupy a given area through time from a pioneer to a climax given area through time from a pioneer to a climax communitycommunity

Autogenic Succession is the changes in environmental Autogenic Succession is the changes in environmental conditions which leads to changes in species conditions which leads to changes in species composition in an ecosystem caused by the biological composition in an ecosystem caused by the biological processes of the organisms themselvesprocesses of the organisms themselves

2 Types of Allogenic Succession are – Primary & 2 Types of Allogenic Succession are – Primary & Secondary SuccessionSecondary Succession

SuccessionSuccession

Primary & Secondary Primary & Secondary SuccessionSuccession

Primary succession occurs when plants Primary succession occurs when plants become established on land which has not become established on land which has not previously been inhabited and where no previously been inhabited and where no soil exists e.g. barren rocksoil exists e.g. barren rock

Secondary succession occurs when plants Secondary succession occurs when plants invade a habitat which was previously invade a habitat which was previously inhabited by other plants and which inhabited by other plants and which therefore has existing soil and some therefore has existing soil and some organic material present e.g. a forest organic material present e.g. a forest destroyed by firedestroyed by fire

Primary succession takes longer than Primary succession takes longer than secondary succession because in primary secondary succession because in primary succession the soil has to be formedsuccession the soil has to be formed

Pioneer to Climax CommunitiesPioneer to Climax Communities

Pioneer species are first to colonise and can withstand Pioneer species are first to colonise and can withstand difficult environmental conditions e.g. drying out (e.g. difficult environmental conditions e.g. drying out (e.g. lichens)lichens)

Climax community is a relatively stable community in Climax community is a relatively stable community in which no further succession takes placewhich no further succession takes place

During succession from a pioneer to a climax community During succession from a pioneer to a climax community all of the following increase:-all of the following increase:--- complexitycomplexity-- species diversityspecies diversity-- habitat varietyhabitat variety-- productivityproductivity-- food websfood webs-- stabilitystability

Degradative SuccessionDegradative Succession

Degradative succession (or Heterotrophic Degradative succession (or Heterotrophic succession) is the sequence of changes succession) is the sequence of changes associated with the decomposition process. For associated with the decomposition process. For instance, when organisms die and begin to instance, when organisms die and begin to decompose, a characteristic sequence of certain decompose, a characteristic sequence of certain species appear associated with that type of species appear associated with that type of organism.organism.

This chain can be used by Forensic This chain can be used by Forensic entomologistsentomologists

Dead Cow > Bacteria>Flies lay eggs on body>Dead Cow > Bacteria>Flies lay eggs on body>Larvae hatch & feed on body> Beetles feed &Larvae hatch & feed on body> Beetles feed &lay eggs>Spiders feed on insectslay eggs>Spiders feed on insects

Loss of Complexity of Loss of Complexity of EcosystemsEcosystems

Loss of complexity can be brought about Loss of complexity can be brought about by:by:

-- monoculturemonoculture

-- eutrophicationeutrophication

-- toxic pollutiontoxic pollution

-- habitat destructionhabitat destruction

8. Intensive Food Production8. Intensive Food Production Monoculture is when a single species is grown over a large areaMonoculture is when a single species is grown over a large area The aim of monoculture is to reduce the complexity of the ecosystem to a The aim of monoculture is to reduce the complexity of the ecosystem to a

single species in order for the farmer to gain highest yields at minimal costs single species in order for the farmer to gain highest yields at minimal costs to get maximum profitto get maximum profit

Population sizes throughout the world are increasing and we thus need more Population sizes throughout the world are increasing and we thus need more foodfood

Hedgerows and fences are taken down to make large fields so machinery Hedgerows and fences are taken down to make large fields so machinery can plough them easily. This removes habitats and shelters and reduces can plough them easily. This removes habitats and shelters and reduces organisms living thereorganisms living there

A monoculture is not a climax community so it is unstable and is at risk from A monoculture is not a climax community so it is unstable and is at risk from competition from other plant species. Therefore humans remove these competition from other plant species. Therefore humans remove these additional plants by hand (organic farming) and by the use of herbicides.additional plants by hand (organic farming) and by the use of herbicides.

Problems with MonocultureProblems with Monoculture Monocultures are highly unstable and are vulnerable to:-Monocultures are highly unstable and are vulnerable to:-

disease caused by bacteria, fungi and virusesdisease caused by bacteria, fungi and viruses attacks from pests (weeds, insects and animals)attacks from pests (weeds, insects and animals) soil erosionsoil erosion adverse weather conditionsadverse weather conditions

The same crops are used year after year so the soil has the same nutrients The same crops are used year after year so the soil has the same nutrients taken from it consistently. Also, after harvesting, the field is cleared of plant taken from it consistently. Also, after harvesting, the field is cleared of plant debris (so nutrient cycles don’t occur).debris (so nutrient cycles don’t occur).

To increase the fertility of the soil fertilisers are used.To increase the fertility of the soil fertilisers are used. Organic fertilisers are manure and composts, whereas inorganic fertilisers Organic fertilisers are manure and composts, whereas inorganic fertilisers

are made from chemicalsare made from chemicals Pesticides (kill pests) and Herbicides (reduce competition by weeds) also Pesticides (kill pests) and Herbicides (reduce competition by weeds) also

contain substances which are toxic to organisms other than those they are contain substances which are toxic to organisms other than those they are intended to killintended to kill

Industrial sites are often polluted with heavy metals such as lead, cadmium Industrial sites are often polluted with heavy metals such as lead, cadmium and mercury which can lead to the death of many organisms, leading to the and mercury which can lead to the death of many organisms, leading to the decrease in complexity of ecosystemsdecrease in complexity of ecosystems

EutrophicationEutrophication Waterways near the fields can become Waterways near the fields can become

polluted by excess nutrients e.g. by polluted by excess nutrients e.g. by adding untreated sewage, runoff of adding untreated sewage, runoff of animal waste from farms, leaching of animal waste from farms, leaching of fertilisers from fieldsfertilisers from fields

This pollution increases the nitrates This pollution increases the nitrates and phosphates in the water systemand phosphates in the water system

The increase in nutrients leads to an The increase in nutrients leads to an explosion of algal growth (algal explosion of algal growth (algal blooms).blooms).

Algal blooms increase oxygen levels in Algal blooms increase oxygen levels in the day by photosynthesis, but oxygen the day by photosynthesis, but oxygen depletion occurs at night due to depletion occurs at night due to respirationrespiration

Algae die and accumulate at bottom of Algae die and accumulate at bottom of water system, and decomposers feed water system, and decomposers feed on them, which decreases the oxygen on them, which decreases the oxygen levels even further, so water plants levels even further, so water plants and larger animals die due to lack of and larger animals die due to lack of oxygen. Eventually species diversity in oxygen. Eventually species diversity in the water is drastically reduced the water is drastically reduced

EutrophicationEutrophication

Coastline Eutrophication

Loch Eutrophication

9. Increase in Energy Needs9. Increase in Energy NeedsAn increase in the human population as An increase in the human population as resulted in an increase in our energy needsresulted in an increase in our energy needs

Fossil Fuels (coal, oil and gas) are finite Fossil Fuels (coal, oil and gas) are finite and will soon and will soon

run out if we continue to use them at the run out if we continue to use them at the present rate present rate

Alternative Energy SourcesAlternative Energy Sources

We need to conserve fossil fuels and use We need to conserve fossil fuels and use alternative sources of energy such as:-alternative sources of energy such as:-

- NuclearNuclear- SolarSolar- WindWind- Hydro-electricHydro-electric- WaveWave- TidalTidal- GeothermalGeothermal- BiofuelsBiofuels

Air Pollution & Greenhouse Air Pollution & Greenhouse GasesGases

When Fossil fuels are burned they release acidic When Fossil fuels are burned they release acidic gases which cause air pollutiongases which cause air pollution

sulphur dioxidesulphur dioxidenitrous oxidenitrous oxidecarbon dioxidecarbon dioxide

Fossil fuels also release greenhouse gases:- Fossil fuels also release greenhouse gases:- carbon dioxidecarbon dioxidewaterwatermethanemethanenitrous oxidenitrous oxideCFC’sCFC’s

Greenhouse EffectGreenhouse EffectSolar energy passes through the Solar energy passes through the atmosphere striking the earth’s atmosphere striking the earth’s surface and thus warms it up, surface and thus warms it up, producing infrared radiation (heat). producing infrared radiation (heat). Most of this radiation is reflected Most of this radiation is reflected back to space but some greenhouse back to space but some greenhouse gases absorb some of this heat, gases absorb some of this heat, making the earth warmer – this is making the earth warmer – this is called the greenhouse effect.called the greenhouse effect.

Called the greenhouse effect Called the greenhouse effect because in a real greenhouse, glass because in a real greenhouse, glass acts as the atmosphere and traps acts as the atmosphere and traps some of the heat energy.some of the heat energy.

When too much heat is absorbed by When too much heat is absorbed by greenhouse gases, global warming greenhouse gases, global warming may occurmay occur

Greenhouse EffectGreenhouse Effect

Illustration 1Illustration 1The earth is covered by a blanket of gases which allow light energy from the sun to reach The earth is covered by a blanket of gases which allow light energy from the sun to reach the earth's surface, where it is converted to heat energy. Most of the heat escapes our the earth's surface, where it is converted to heat energy. Most of the heat escapes our atmosphere, but some is trapped. This natural effect keeps the earth warm enough to atmosphere, but some is trapped. This natural effect keeps the earth warm enough to sustain life.sustain life.

Illustration 2Illustration 2Human activity such as burning fossil fuels (coal, oil and natural gas) and land clearing is Human activity such as burning fossil fuels (coal, oil and natural gas) and land clearing is creating creating more more greenhouse gases. This traps more heat, so the earth becomes hotter.greenhouse gases. This traps more heat, so the earth becomes hotter.

Global WarmingGlobal Warming

Global warming may cause climate Global warming may cause climate change (e.g. changes in temperature, change (e.g. changes in temperature, rainfall levels, sea levels) which could rainfall levels, sea levels) which could affect the distribution of many affect the distribution of many different speciesdifferent species

Scientists predict that climate change Scientists predict that climate change will happen too fast for organisms to will happen too fast for organisms to adapt or move so it could result in a adapt or move so it could result in a decrease in species diversity decrease in species diversity

Global Warming Global Warming Effects on AnimalsEffects on Animals

Increased storms damaging the breeding colonies of Increased storms damaging the breeding colonies of albatross, already facing heavy pressure from albatross, already facing heavy pressure from accidental capture on long-line fishing hooks accidental capture on long-line fishing hooks

Sea level rise destroying beach nesting sites for sea Sea level rise destroying beach nesting sites for sea turtlesturtles

Seals and wading birds also face destruction of their Seals and wading birds also face destruction of their coastal habitats coastal habitats

Warmer seas could lead to some turtle species Warmer seas could lead to some turtle species becoming entirely female, as water temperature becoming entirely female, as water temperature strongly affects the sex ratio of hatchlings strongly affects the sex ratio of hatchlings

The spreading extent of the Sahara desert could The spreading extent of the Sahara desert could threaten long-range travellers such as the swallow, as threaten long-range travellers such as the swallow, as they will be unable to "fuel up" in previously fertile they will be unable to "fuel up" in previously fertile regions on the desert's edge. regions on the desert's edge.

Coral BleachingCoral Bleaching ““Coral Bleaching” is an example of how global warming might affect the Coral Bleaching” is an example of how global warming might affect the

distribution and diversity of different species.distribution and diversity of different species.

Colourful Coral reefs are made up of a symbiotic relationships of coral Colourful Coral reefs are made up of a symbiotic relationships of coral polyps (which secret a skeleton of white calcium carbonate) and a polyps (which secret a skeleton of white calcium carbonate) and a unicellular-coloured algae called zooanthellae.unicellular-coloured algae called zooanthellae.

Zooanthellae provides the coral polyps with nutrients produced from Zooanthellae provides the coral polyps with nutrients produced from photosynthesis and the coral polyps provide the zooanthellae with a photosynthesis and the coral polyps provide the zooanthellae with a protected environment and lots of carbon dioxide for photosynthesis – a protected environment and lots of carbon dioxide for photosynthesis – a mutualistic relationshipmutualistic relationship

Temperature increase causes the algae zooanthellae to leave the coral, Temperature increase causes the algae zooanthellae to leave the coral, leaving just the white skeleton – thus called coral bleachingleaving just the white skeleton – thus called coral bleaching

If temperature increase is reversed zooanthellae may repopulate the reef If temperature increase is reversed zooanthellae may repopulate the reef and the coral may recover, of not the coral polyps eventually die.and the coral may recover, of not the coral polyps eventually die.

Coral BleachingCoral Bleaching

Sun Coral in ideal temperatures

Coral bleaching in process

10. Pollution10. Pollution

Pollution is the negative effect of a harmful substance on the Pollution is the negative effect of a harmful substance on the environmentenvironment

Pollution may cause the following biological effects:- Pollution may cause the following biological effects:- the appearance of a speciesthe appearance of a species the disappearance of a speciesthe disappearance of a species changes in community structure and functionchanges in community structure and function changes in behaviourchanges in behaviour changes in productivity, energy flow and nutrient cyclingchanges in productivity, energy flow and nutrient cycling

The 4 ecosystems that can be effected by pollution are:-The 4 ecosystems that can be effected by pollution are:- sea (oil spills, dumping of radioactive waste, dumping of toxic waste)sea (oil spills, dumping of radioactive waste, dumping of toxic waste) air (emissions from cars, planes, industry)air (emissions from cars, planes, industry) land (landfill sites, domestic rubbish)land (landfill sites, domestic rubbish) freshwater (agricultural run off, organic sewage) freshwater (agricultural run off, organic sewage)

Measuring PollutionMeasuring Pollution Freshwater can be polluted by organic material by the dumping of untreated Freshwater can be polluted by organic material by the dumping of untreated

sewagesewage This organic sewage provides a rich food source for microorganisms that This organic sewage provides a rich food source for microorganisms that

feed, reproduce and use up the oxygen in the water. Other organisms such feed, reproduce and use up the oxygen in the water. Other organisms such as fish die.as fish die.

Biodegradable organic pollutants include sewage, farm waste and industrial Biodegradable organic pollutants include sewage, farm waste and industrial wastewaste

Ecosystems need continually monitoring to ensure they are free from Ecosystems need continually monitoring to ensure they are free from harmful levels of pollutants. Water can be tested directly or indirectly.harmful levels of pollutants. Water can be tested directly or indirectly.

Direct methods of water testing are:-Direct methods of water testing are:- ColourColour TurbidityTurbidity Dissolved Oxygen levelsDissolved Oxygen levels PHPH Biochemical Oxygen Demand (BOD)Biochemical Oxygen Demand (BOD) OdourOdour TemperatureTemperature Ammonia, nitrate, chloride, phosphorus levelsAmmonia, nitrate, chloride, phosphorus levels

BOD TestingBOD TestingThe BOD (Biochemical Oxygen Demand) test is a water quality The BOD (Biochemical Oxygen Demand) test is a water quality test that measures the levels of dissolved oxygen in the water. test that measures the levels of dissolved oxygen in the water. It is used to estimate the levels of biodegradable organic It is used to estimate the levels of biodegradable organic material there is.material there is.

High BOD levels indicate a high level of organic pollution in the High BOD levels indicate a high level of organic pollution in the water, and a low BOD level indicates a low level of organic water, and a low BOD level indicates a low level of organic pollution in the waterpollution in the water

BOD Test – 2 samples of water are taken from the same site. BOD Test – 2 samples of water are taken from the same site. Sample 1 is tested immediately, and Sample 2 is incubated for Sample 1 is tested immediately, and Sample 2 is incubated for 5 days in the dark at 20°C and then the BOD is taken. 5 days in the dark at 20°C and then the BOD is taken.

The difference in dissolved oxygen content of the 2 samples The difference in dissolved oxygen content of the 2 samples shows the amount of oxygen consumed by microbial respiration shows the amount of oxygen consumed by microbial respiration as bacteria break down the organic matter in the sample.as bacteria break down the organic matter in the sample.

Biological MonitoringBiological Monitoring

Indicator species give information about Indicator species give information about the environment that it is living inthe environment that it is living in

Biological Monitoring is an indirect Biological Monitoring is an indirect measure of water qualitymeasure of water quality

A susceptible species can be used as an A susceptible species can be used as an indicator species, as their disappearance indicator species, as their disappearance from a habitat that they were in previously from a habitat that they were in previously indicates that the environmental conditions indicates that the environmental conditions have changed. For example, lichens have changed. For example, lichens disappearing indicates increased levels of disappearing indicates increased levels of sulphur dioxidesulphur dioxide

A favoured species can tolerate a wide A favoured species can tolerate a wide range of environmental conditions, so range of environmental conditions, so cannot be used as an indicator speciescannot be used as an indicator species

Chemical Chemical TransformationsTransformations

Once chemicals have been released into the environment, their chemical Once chemicals have been released into the environment, their chemical nature changes due to their interactions with each other and the nature changes due to their interactions with each other and the environment, this is called CHEMICAL TRANSFORMATIONenvironment, this is called CHEMICAL TRANSFORMATION

Sometimes chemical transformations can turn relatively safe chemicals Sometimes chemical transformations can turn relatively safe chemicals into toxic onesinto toxic ones

Biotransformation of the heavy metal mercury by Clostridium, Neurospora Biotransformation of the heavy metal mercury by Clostridium, Neurospora and Pseudomonas. These organisms can all methylate metallic mercury and Pseudomonas. These organisms can all methylate metallic mercury changing it from a moderately toxic chemical into a highly toxic one that changing it from a moderately toxic chemical into a highly toxic one that change damage kidney, liver and brain tissue in humanschange damage kidney, liver and brain tissue in humans

When a chemical accumulates in the tissues of an organism it is called When a chemical accumulates in the tissues of an organism it is called BIOACCUMULATIONBIOACCUMULATION

BIOMAGNIFICATIONBIOMAGNIFICATION is when some toxins become very harmful is when some toxins become very harmful because they become more concentrated in successive trophic levels of a because they become more concentrated in successive trophic levels of a food web. This is due to the fact that some chemicals (e.g. chlorinated food web. This is due to the fact that some chemicals (e.g. chlorinated hydrocarbons) accumulate in specific tissues, especially fat. hydrocarbons) accumulate in specific tissues, especially fat.

DDTDDT DDT (Dichlorodiphenyltrichloroethane) is an insecticide that was commonly used DDT (Dichlorodiphenyltrichloroethane) is an insecticide that was commonly used

during the 1940’s & 1950’s. It was used to kill insects like mosquitoes that carried during the 1940’s & 1950’s. It was used to kill insects like mosquitoes that carried malaria and saved many lives.malaria and saved many lives.

DDT is no longer used due to its long-term lethal side effects. DDT is no longer used due to its long-term lethal side effects. DDT bioaccumulates in the body fats of organisms.DDT bioaccumulates in the body fats of organisms. DDT is biomagnified through the food chain, so at each tropic level the DDT is biomagnified through the food chain, so at each tropic level the

concentration of DDT increasesconcentration of DDT increases DDT breaks down to form a stable compound called DDE which thins the shells of DDT breaks down to form a stable compound called DDE which thins the shells of

many birds reducing the survival rate of many birds (e.g. osprey)many birds reducing the survival rate of many birds (e.g. osprey) Large scale resistance to DDT has evolved with 35 species of malarial mosquitoes Large scale resistance to DDT has evolved with 35 species of malarial mosquitoes

now resistantnow resistant Areas of the world that did not use DDT show high levels of the chemical. Inuit Areas of the world that did not use DDT show high levels of the chemical. Inuit

people from Greenland have high levels of DDT in the tissues acquired from people from Greenland have high levels of DDT in the tissues acquired from consuming seals that had visited DDT regionsconsuming seals that had visited DDT regions