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EcologyEcologyClassical Population BiologyClassical Population Biology

Mark MayoMark Mayo

Cypress CollegeCypress College

Last update 8/27/13

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Terms of Ecological Terms of Ecological Endearment Endearment

**habitathabitat – place where you live; place where you live;

the physical locationthe physical location– has distinguishing has distinguishing

physical and chemical physical and chemical featuresfeatures

– is where individuals of is where individuals of a species normally livea species normally live

– is occupied by various is occupied by various speciesspecies

communitycommunity – all – all organisms that organisms that live in the same live in the same habitathabitat

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Five factors that determine Five factors that determine community structure community structure

the habitat’s temperature, rainfall and soil the habitat’s temperature, rainfall and soil conditionsconditions

available food supply – both the quantity available food supply – both the quantity and qualityand quality

adaptive traits that allow each species in adaptive traits that allow each species in the community to survive and use the the community to survive and use the resources in the habitatresources in the habitat

species interactions: predation, parasitism, species interactions: predation, parasitism, competition, beneficial interactionscompetition, beneficial interactions

changes in the habitat and changes in the changes in the habitat and changes in the populationpopulation

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** Certain regions favor and Certain regions favor and support a greater quantity of support a greater quantity of

species species

arcticarctic vsvs tropics tropics

The number of coexisting species is highest in the tropics and decreases greatly toward the poles

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Niche Niche

** Definition Definition: : the sum of all activities the sum of all activities and relationships in which a species and relationships in which a species performs in order to allow survival performs in order to allow survival and reproductionand reproduction– JobJob– The functions it performs in the The functions it performs in the

population of community population of community – Sometimes it is which other organism it Sometimes it is which other organism it

eatseats

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Interactions – symbioses Interactions – symbioses (the word means to live together)(the word means to live together)

Neutral interactionNeutral interaction – Canadian Lynx and – Canadian Lynx and grasses (0/0) – only indirect relationship grasses (0/0) – only indirect relationship

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Interactions – symbiosesInteractions – symbioses

** Commensalism Commensalism – – one benefits/one benefits/one neutral - neither harmed or helpedone neutral - neither harmed or helped (bird+ / tree-o) (bird+ / tree-o)

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Interactions – symbiosesInteractions – symbioses

** PredationPredation - one - one benefits/ one is harmed benefits/ one is harmed (killed) (hawk+/mouse-)(killed) (hawk+/mouse-)– Animals that feed on other Animals that feed on other

animalsanimals– The one that eats is the The one that eats is the

predatorpredator– The one eaten is the The one eaten is the preyprey– They do not live on or in their They do not live on or in their

preyprey– The prey may die or may live The prey may die or may live

if only part or the whole prey if only part or the whole prey is damagedis damaged

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Interactions – symbiosesInteractions – symbioses

PredationPredation– ** Cyclic in nature Cyclic in nature – increase in prey leads to – increase in prey leads to

increase in predators and vice versaincrease in predators and vice versa– More food supports more prey (good rainfall More food supports more prey (good rainfall

year) and vice versayear) and vice versa– The more prey eaten leads to more predators The more prey eaten leads to more predators

until prey is insufficient for predator populationuntil prey is insufficient for predator population– Predator numbers decline until past what prey Predator numbers decline until past what prey

will supportwill support– The cycle begins again after a The cycle begins again after a short lag short lag

periodperiod

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Interactions – symbiosesInteractions – symbioses

Parasitism*Parasitism* – – symbiosis where one symbiosis where one benefits/one harmed, but usually not killedbenefits/one harmed, but usually not killed

(flea+/dog- ; intestinal worms+/man- ; (flea+/dog- ; intestinal worms+/man- ; lice+/children-)lice+/children-)

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Interactions – symbiosesInteractions – symbioses

ParasitismParasitism– ** parasites live on or in the host parasites live on or in the host

organismorganism– most hosts survive or parasite is out of foodmost hosts survive or parasite is out of food– careful balance between needs of parasite and careful balance between needs of parasite and

those of the hostthose of the host– parasites usually weaken the hostparasites usually weaken the host– parasites make predation of the host more parasites make predation of the host more

likelylikely– parasites reduce host’s ability to mate & parasites reduce host’s ability to mate &

produce offspring produce offspring

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Interactions – symbiosesInteractions – symbioses

ParasitismParasitism Kinds of parasitesKinds of parasites

– microparasitesmicroparasites – bacteria, – bacteria, protozoans, viruses, fungiprotozoans, viruses, fungi

– macroparasitesmacroparasites – worms – worms (round and flat), arthropods (round and flat), arthropods like: fleas, ticks, mites, licelike: fleas, ticks, mites, lice

– social parasitessocial parasites – cuckoo – – cuckoo – lays egg in another species lays egg in another species nestnest cuckoo hatches first and throws cuckoo hatches first and throws

out other eggsout other eggs the other species feeds and the other species feeds and

cares for cuckoo only!cares for cuckoo only!

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Interactions – symbiosesInteractions – symbioses

ParasitismParasitism– It is less advantageous for a It is less advantageous for a

parasite to kill the host – parasite to kill the host – it is it is an evolutionary adaptationan evolutionary adaptation to to keep the host healthy enough keep the host healthy enough to allow parasite reproduction to allow parasite reproduction and the life cycle of the and the life cycle of the parasite to completeparasite to complete

– Sometimes we employ parasitic Sometimes we employ parasitic wasps for biological control of wasps for biological control of certain insects (sometimes certain insects (sometimes results not exactly as planned)results not exactly as planned)

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Interactions – symbiosesInteractions – symbioses

MutualismMutualism – both – both benefit benefit (insects+/flowers+)(insects+/flowers+)– flowers/insects flowers/insects

(flowers get assistance (flowers get assistance in pollination – insects in pollination – insects get food)get food)

– yucca plant and yucca yucca plant and yucca moth moth (yucca-pollination – (yucca-pollination – moth gets housing and moth gets housing and foodfood

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Interactions – symbiosesInteractions – symbioses CompetitionCompetition

– ** interspecific competitioninterspecific competition – – two different speciestwo different species occupy occupy the same nichethe same niche and use same and use same food source (small shark and food source (small shark and tuna both want mackerel for tuna both want mackerel for food). It is not usually as food). It is not usually as intense as intraspecific intense as intraspecific competition because they competition because they have similar, but not identical have similar, but not identical requirementsrequirements

– intraspecific competitionintraspecific competition – – competition within the same competition within the same species – very intense species – very intense because they have identical because they have identical requirementsrequirements

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Interactions – symbiosesInteractions – symbioses

CompetitionCompetition– Competitive exclusionCompetitive exclusion – one species is – one species is

better able to compete for food the better able to compete for food the other species dies out or moves or other species dies out or moves or switches to an alternate food sourceswitches to an alternate food source

– Where two species coexist in nature Where two species coexist in nature competitive interactions suppress competitive interactions suppress population growth in both speciespopulation growth in both species

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Interactions – coevolution Interactions – coevolution ** Mimicry Mimicry -physical or -physical or

behavioral resemblance of behavioral resemblance of one species to another to one species to another to benefit itself or sometimes benefit itself or sometimes benefit both species.benefit both species.– example – a certain moth example – a certain moth

tastes bad and has bright tastes bad and has bright colorscolors

– natural selection of a second natural selection of a second moth species favors moths moth species favors moths who look like the bad tasting who look like the bad tasting species (bright colors)species (bright colors)

– color patterns may be similarcolor patterns may be similar– examples in nature: moths, examples in nature: moths,

wasps, wing patterning wasps, wing patterning

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Interactions – coevolutionInteractions – coevolution ** Warning colorationWarning coloration - - is intended not to is intended not to

camouflagecamouflage an organism but to an organism but to make it more make it more noticeablenoticeable. Such . Such bright colorationbright coloration is found is found among animals that have natural defenses among animals that have natural defenses that they use to deter or fend off predators.that they use to deter or fend off predators.– These defenses can take many formsThese defenses can take many forms– An animal may simply cause a An animal may simply cause a

disagreeable smell disagreeable smell (such as a skunk's odor)(such as a skunk's odor)

– An animal may actually cause pain An animal may actually cause pain (as from bee's sting) or even death (as from bee's sting) or even death (as from snake's venom). (as from snake's venom).

– Many of these animals are brightlyMany of these animals are brightly colored, presumably as a warning colored, presumably as a warning to potential aggressors. to potential aggressors.

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Interactions – coevolutionInteractions – coevolution CamouflageCamouflage – aka – aka

**CCrypticryptic colorationcoloration helps disguise an helps disguise an animal so that it is less animal so that it is less visible to predators or visible to predators or prey. prey.

One of the most One of the most common types of common types of cryptic coloration is cryptic coloration is background matchingbackground matching

Octopus camouflageOctopus camouflagevideo clipvideo clip

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Interactions – coevolutionInteractions – coevolution

CamouflageCamouflage– Many helpless animals have Many helpless animals have

developed colors and markings developed colors and markings that match their surroundings that match their surroundings in order to hide from in order to hide from predators. predators.

– Fish eggs and microscopic Fish eggs and microscopic zooplankton, for example, are zooplankton, for example, are transparent and nearly transparent and nearly invisible as they drift in the invisible as they drift in the upper layers of oceans and upper layers of oceans and freshwater lakes freshwater lakes

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Interactions – coevolutionInteractions – coevolution

CamouflageCamouflage– A fawn's spotted coat A fawn's spotted coat

camouflages the animal camouflages the animal against the speckled against the speckled forest floorforest floor

– Some animals attempt to Some animals attempt to camouflage themselves camouflage themselves physicallyphysically

– A decorator crab A decorator crab cements bits of algae, cements bits of algae, seaweed, and other seaweed, and other ocean debris onto its ocean debris onto its shell so that it resembles shell so that it resembles the ocean floor.the ocean floor.

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Interactions – coevolutionInteractions – coevolution Alluring colorationAlluring coloration - -

animals are colored so animals are colored so that a predator's that a predator's attention is drawn to a attention is drawn to a non-vital part of the non-vital part of the animal's bodyanimal's body– lizard known as the lizard known as the

blue-tailed skink has a blue-tailed skink has a bright blue tail that the bright blue tail that the animal can shed at will animal can shed at will with no harm to itselfwith no harm to itself

– Potential predators are Potential predators are attracted to the tail; if attracted to the tail; if they attack the tail, the they attack the tail, the skink sheds it and darts skink sheds it and darts away unharmed. away unharmed.

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Interactions – coevolutionInteractions – coevolution Alluring colorationAlluring coloration - -

animals are colored so animals are colored so that a predator's that a predator's attention is drawn to a attention is drawn to a non-vital part of the non-vital part of the animal's bodyanimal's body– In butterflies the spot In butterflies the spot

looks like an eye for looks like an eye for confusionconfusion

– In fish, it draws attention In fish, it draws attention from the vital head to the from the vital head to the tail with the larger “eye” tail with the larger “eye” at the opposite endat the opposite end

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Interactions – coevolutionInteractions – coevolution ** Moment of truth defensesMoment of truth defenses – action by – action by

prey just before death that is unexpected prey just before death that is unexpected by predatorby predator– if you hit a shark on the nose it MAY leave you if you hit a shark on the nose it MAY leave you

alonealone– rapid turn by monkeys just before capture – with rapid turn by monkeys just before capture – with

aggressive stanceaggressive stance– stink bug turns and sprays odorous liquid just stink bug turns and sprays odorous liquid just

before capturebefore capture

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Succession Succession

** Definition Definition - - SuccessionSuccession is the is the gradual replacement of one gradual replacement of one community with anothercommunity with another

Ecosystems change over time, due to Ecosystems change over time, due to **sediment buildupsediment buildup, introduction of , introduction of new species, extinction of old new species, extinction of old species, and other factors. species, and other factors.

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SuccessionSuccession

** Primary Primary successionsuccession occurs occurs when when land is first land is first formed. formed.

Microbes, Microbes, lichens and lichens and mosses must mosses must create soilcreate soilbefore other before other plants can plants can grow. grow.

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SuccessionSuccession

** Primary Primary succession occurs succession occurs when when land is first land is first formed. formed.

Microbes, Microbes, lichens and lichens and mosses must mosses must create soilcreate soilbefore other before other plants can plants can grow. grow.

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SuccessionSuccession

Mt. St. HelensMay 18, 1980

Devastation created new habitats devoid of any living organisms.

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SuccessionSuccessionMount St. HelensMount St. Helens

BeforeBefore AfterAfter

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SuccessionSuccession ** Secondary Secondary

succession succession occurs when occurs when succession must succession must start over after start over after the destruction the destruction of a climax of a climax community. community.

This is This is Mount St. Mount St. Helens in the Helens in the process of process of secondary secondary successionsuccession

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SuccessionSuccession

SecondarSecondary y successiosuccessionn

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SuccessionSuccession

Secondary Secondary successionsuccession

Weather, tsunamis, Weather, tsunamis, volcanoes and volcanoes and forest fires can forest fires can change even change even climax climax communities and communities and thus start thus start succession over succession over againagain

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SuccessionSuccession A A climax communityclimax community is is

the ultimate goal of the ultimate goal of succession. It is marked succession. It is marked by the domination of by the domination of long-lived species and long-lived species and great diversity. great diversity.

A climax community is A climax community is a stable group of plants a stable group of plants and animals that is the and animals that is the end result of the end result of the successionalsuccessional process. process.

The redwood forest of The redwood forest of California is a climax California is a climax community. community.

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Keystone SpeciesKeystone Species A A ** keystone specieskeystone species is the is the

most dominant species in most dominant species in the communitythe community– They can dictate community They can dictate community

structurestructure– This species can be This species can be

demonstrated by removal of demonstrated by removal of keystone species from keystone species from communitycommunity

– Robert Paine performed Robert Paine performed experiments using a experiments using a starfishstarfish

– StarfishStarfish controlled entire controlled entire community population levels community population levels of mussles, chitons, limpets of mussles, chitons, limpets and barnacles (all are starfish and barnacles (all are starfish prey)prey)

– When the When the starfishstarfish were were removed: mussles took overremoved: mussles took over

musslesmusslesbarnaclebarnacle

chitonchiton

starfishstarfish

limpetlimpet

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The Importance of DiversityThe Importance of Diversity Diversity in an ecosystem Diversity in an ecosystem

helps prevent mass helps prevent mass extinctions and genetic extinctions and genetic problems. problems. – A monoculture is a one-A monoculture is a one-

species ecosystem. A corn species ecosystem. A corn field is an example. field is an example.

– Complexity provides Complexity provides stability in that if a new stability in that if a new species is introduced or an species is introduced or an old one becomes extinct, it old one becomes extinct, it is much less likely for the is much less likely for the whole system to stop.whole system to stop.

– Monocultures are Monocultures are massively disrupted when massively disrupted when a new species is a new species is introduced.introduced.

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Ecological Limiting FactorsEcological Limiting Factors

Limiting factorsLimiting factors in an ecosystem control in an ecosystem control population and, to some extent, diversity. population and, to some extent, diversity.

Examples of limiting factors: Examples of limiting factors: – WaterWater– PhosphorusPhosphorus– SunlightSunlight– nitrogen nitrogen

The Law of Limiting Factors:The Law of Limiting Factors: "The factor "The factor that is most deficient determines the that is most deficient determines the presence or absence of any given presence or absence of any given organism."organism."