Unit 9: Living things in their environment

Index1. Environmental factors2. Adaptation of organisms to the environment3. How living things change their environments4. Populations5. Communities

1. Environmental factors

Ecological factors

(characteristics of the environment)

AbioticPhysical and

chemical conditions

Biotic Organisms

LIMITING FACTOR = variable that limits or prevents a population from expanding.

2. Adaptations of organisms to the environment

Adaptation

Morphological

Physiological

Behavioural

A morphological adaptation involves some part of an animal's body, such as the size or shape of the teeth, the animal's body covering, or the way the animal moves. 

MimicryColoration

Protective Resemblance

MigrationHibernation

Playing Dead (opossum, zarigüeya)

Behaviour adaptations include activities that help an animal survive.  Behaviour adaptations can be learned or instinctive.

Types of organisms according to the habitat

Generalist organisms

They are able to survive in a greater variety of environmental conditions

Specialist organisms

They cannot tolerate significant changes to their environment

Temperate forest more generalist organisms because of the variations

Tropical forest more specialist organisms due to the stable climate

2.1 Adaptations to water scarcity

Water is stored in special tissues

Hard, small leaves

Deep and extensive root systems

Drought resistant seeds

2.2 Adaptations to temperature changes Skin insulation

Metabolic rate slows down in winter

Organs grow underground

Leaves that fall in autumn

Individuals come together to increase the temperature around them

2.3 Adaptations to sunlight

Algae have different pigments which allow them live at different dephts: green, brown and red

Plants grow in the direction of the light

2.4 Adaptations to salt concentration

Saltwater fish excrete salt through their gills and their urine is very concentrated.

Freshwater fish eliminate the water by expelling large amounts of urinethat has a low salt content. They don’t drink.

2.5 Adaptations to lack of oxygen

Increase in red blood cells and haemoglobin.

Increase in lung capacityOrganisms living in marine caves have lower metabolic rates and accumulate lipids, which contain more energy than carbohydrates and increase buoyancy.

2.6 Adaptations to lack of food

Storing energy reserves in their body

Storing food in hidden places

Migrating to find food

3. How living things change their environments

Photosynthesis contributes to

increase oxygen in the atmosphere

and decreases the amount of CO2

Plant roots and the action of

some animals break up rocks

Erosion

Coral skeletons can create

islands

Human being impact

Activities 1, 2, 3, 4, 5, 6 and 7 page 167

4. Populations

Colonies

• They are connected and related to each other because they are produced by asexual reproduction from the same parent

4.1 Intraspecific relationships

Family groups

• The descendants come from a pair of animals and they stay together

Caste system of social insects

• They come from the same mother and have differences which dictate their role in the community.

Social groups

• They live together but they must not be related. Sometimes these groups are transitory, such as during migrations.

gnus

storks

4.2 Population dynamics

Populations are not always constant. They undergo changes.

When the population becomes too big, there are negative effects which limit reproduction lack of resources competition diseases

Latent phase

Exponential phase

Stationary phase

(maximum number of individuals in a population)

Biotic potential = difference between the birth rate and the death rate

4.3 Population growth strategies

R-strategists

They produce many descendants but they do not take care of them.That’s why many of the descendants die.They usually live in unstable habitats. Their populations vary a lot. Usually small animals.

Bacteria, molluscs, insects…

K-strategists

They produce just a few descendants and they invest a large quantity of resources caring for them.They live in a stable habitat and they are very well adapted to it.

Activities 10, 11, 13, 15, 16, 17, 18 page 171

5. CommunitiesA community is a set of populations of different organisms that livetogether in the same geographical area within a particular habitat.

5.1 Ecological succession

Ecological succession is the sequential order in which plant communities and the animal species associated with them change over time.

A. Primary succession

1. An uninhabited zone is colonised by pioneer organisms (they have few nutritional requirements)

2. The soil is progressively enriched and biodiversity increases

3. The progressive evolution leads to a community that is very stable.This is called the climax community.

The species which inhabit each ecosystem as the climax communityvary depending on the biome to which they belong to (climate, soil…)

Mature Mediterranean ForestTundra

Video: Primary Succession and Stages of Primary Successionhttps://www.youtube.com/watch?v=vNHnwHaSolA https://www.youtube.com/watch?v=TLpc71YOtcE

B. Secondary succession

Regression = a community loses an important part of its populations.This can be caused by events such as natural disasters, climate change,erosion…

It is a new evolutionary process which takes place after a regression.The soil must not be formed because it is still there.

5.2 Communities and the soil

The types of plants and therefore, the animals that develop in and on a soil depend on its composition, structure and thickness.

Soil takes a long time to form, so its destruction is a major loss for communities and it can cause a regression in their evolution.

Soil can be considered as a “potentially renewable resource”

The different types of soil depend on

Climate Type of bedrock Microorganisms that live there

Parts of a soil

Horizon A•Humus (organic component), which comes from the remains of living things

Horizon B, •with mineral particles

Horizon C,• made up of fragments form the bedrock

Bedrock

A

B

C

5.3 Interspecific relationships (within communities)

INTERACTION SPECIE A SPECIE B

Mutualism + +Commensalism + 0Inquilinism + 0

Symbiosis + +Parasitism + -Predation + -Competition - -

A. Mutualism (+,+)

Some birds and rhinoceros or zebras

Insects and flowers

Clownfish and sea anemones

Moray and some cleaning shrimps

B. Comensalism (+,0)

Shark and remora fish

Scarvengers

Bird’s nest fern -Grows on a tree-To obtain sunlight

Tree-not receive any benefits or harm

C. Inquilinism (+,0)

Barnacles - get shelter

Mussels- Not affected

Hermit crabs and gastropod shells

D. Symbiosis (+,+)

Lichens: a fungus and an algaeFungus provides shelter and humidity

Algae produces organic matter

Nodule (it contains nitrogenfixing bacteria)

- The plant needs nitrogen, which comesfrom the atmosphere. The bacteriafix it.

Leguminous plant root:Provides shelter and food for the bacteria

Symbiotic bacteria that live in our intestine

E. Parasitism (+,-)

The parasite benefits from the host, causing harm to him

Wood fungus (parasite)obtains food and shelter from tree

Host (Tree) is weakened and may die

Tapeworms Fleas

Barnacles on whales

Brood Parasitism Mosquito on Humans

Rafflesia (parasite plant) obtains food and shelter from the tree

Host (Tree) is weakened and may die

-Plant Parasites-Mistletoe is plant parasite

(Muérdago)

The rat is the victim (prey)

The snake eats and kills the rat (predator)

F. Predation (+,-)

-Herbivoresconsumption of plant or algal tissue

-Carnivoresconsumption of animal tissue

-Omnivoresconsumption of both plant and animal tissues

-Detritivoresconsumption of dead organic material

G. Competition (-,-)

They compete for the same resource: territory, food, water, light…

Glossary biotic potential carrying capacity ecological successionclimax community symbiosis

Activities 20, 21, 22, 23,24 and 26 page 175