Environment and Evolution

Adaptations Examples

Polar bear - black skin to absorb heat, white fur to camoflauge, ears have small surface area to volume ratio so they don't loose heat quickly, big paws to spread out weight and smash ice

Camel - long eyelashes to protect eyes from sand, hump to store fat, live without water for two weeks, extra eyelid = protect eyes from sand, feet allow them to walk on sand, can close nostrils so no sand gets in

African Elephant - big ears so they loose heat quiclky , tusks to fight predators, long trunk to reach food, ears have a large surface area to volume ratio

Horned Lizard, skin colour allows to camoflauge in rocks, horns to protect itself, claws allow them to walk on rocks

Plant adaptation -  Cactus - spikes to stop animals eating it, long roots to get water but shallow to absorb water, small surface area to reduce water loss, thick stem to store water

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Why Animals Adapt & Surface Area To Volume Ratio

Having adaptations enables the animal to survive because it gives them qualities suitable for their environment. Eg fur for cold climates. They also have defence/ offence weapons so they can survive and thrive

Larger penguins have a smaller surface area to volume ratio compared to smaller penguins therefore they will loose less heat

Organisms that live in extreme conditions such as in salt, high pressure and high temperatures are called extremophiles

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Predators and Prey

Why the population of predators and prey is changing:

As the population of prey increases, so does the populatin pf the predator as there is more food available. As the population of prey decreases so does the population of predator as there is less food available. If the population of predator decreases, the population of the prey increases as it is not being eaten.

Animals compete for: teritory, food, mates

Plants compete for: nutirents, space, light, water

Nutrients - help the plant grow and make food, Space - for leaves and roots to grow, Light - photosynthesis, Water - life processes and transport around the plant

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Measuring Environmental Change

Living organisms are affected by changes in the environment.

We can measure environmental change using non-living factors such as:

temperature change, levels of sunlight, weather changes, acidity of rain water, measuring levels of air pollution, humidity levels

We can measure environmental change using living factors such as:

population change, changes in growth paterns of plants

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Energy in Biomass

Radiation from the sun is a source of energy. This energy is absorbed by plants amd algae when photosynthesis occurs. This light energy is converted to chemical energy. This energy is stored in cells of plants.

Biomass is the mass of living material. The amount of energy transferred through the food chain isn't always 100% as some of it is being used in respiration and excretion. The further up the food chain, the less energy transferred.

The amount of energy and material contained in the biomass of organisms is less at each stage of the food chain. This is because not all organims are eaten by the stage above, some is lost as waste, converted to its own biomass.


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The Carbon Cycle

Carbon is taken in by:

- photosynthesis

- when it is dissolved in oceans

- when it is locked up in coal/ fuel

Carbon is released by:

- burning (combustion)

- respiration

- decomposers respiring

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The Decay Process

Living things will take materials such as nutriens from the environment when they grow. The materials are recycled and returned to the environment when the living things die and decay. The decomposers can be microorganisms (bacteria and fungi) or detritus feeders (maggots and some types of worms.) They all break down the dead material, Microorganisms work best in warm, moist conditions with plenty of oxygen.

The decay process is important to ensure we maintain a stable community. Nutrients taken in by plants are returned to the environment for other plants to use.

They decay process is used in compost heaps where microorganisms break down grass cutitngs, vegeatble peeling etc to maake compost which can be used as a fertilliser. It is also used in sweage treatment plants where microorganisms break down bodily waste.

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Sexual And Asexual Reproduction

Sexual reproduction involves reproduction with sex cells from 2 people. Eg egg (ovum) and sperm. The exact same characteristics from parents will not be inherited.

Asexual reproduction involves genes being inherited from one parent only. Therefore the offspring will have the same characteristic as the parent. Cells will divide to produce identical copies of genes eg strawberry plants.

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Cloning Plants

1) get a plant you would like to clone

2) take a cutting of that plant (eg cut away one if its leaves) that contains its DNA

3) apply rooting powder to the leaf

4) put the leaf in soil to grow and water it

5) a new plant grows as an identical clone of the first plant

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Factors Causing Variation

Factors which wold cause variation:


- genes

- mutations


- amount of sunlight (plants)

- amount of water (plants

- atmosphere conditions (plants)

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Cloning Animals

1) take early embryo (a cluster of identical cells)

2) divide embryo into several individual cells

3) each cell grows into identical embryo in lab

4) transfer embryos into host mother, which have been given hormones to get them ready for pregnancy

5) identical cloned animals are born. They are not biologically related to their mothers

Advantages: can get more of the animal with best features, help endangered species, more off-spring produced by animal than would naturally occur

Disadvantages: ethical issues, more suceptable to diseases, early health problems, costly and skilled process

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Adult Cell Cloning

1) nucleus is removed from the adult that needs to be cloned

2) remove everything from the ovum of another animal

3) place the nucleus into the empty ovum

4) electric shock given to form embryo when cell division occurs

5) when the embryo is developed into a ball of cells, it is implanted into the womb of an adult

6) the adult gives birth to a clone of the sheep that the nucleus was removed from

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