Ecosystems

Ecology?

the study of the relationships between organisms and their environment

What is an ecosystem made up of?

all the living organisms that interact with one another as well as all the physical factors in a defined ecosystem

What do the person or team carrying out the study of the ecosystem define?

they define the boundaries of a particular ecosystem

All ecosystems are dynamic?

constantly changing

What are all ecosystems being dynamic a result of?

living organisms present and the environmental conditions

The two types of factors that effect an ecosystem?

biotic and abiotic factors

Biotic?

living factors

3 examples of biotic factors?

predators, disease, competition for resources

Abioitc?

non-living

4 examples of abiotic factors?

soil pH, oxygen availability, temperature, water availability and light intensity

Why are most plants directly affected by light availability?

light is required for photosynthesis

Why is a greater availability of light good?

the greater the availability of light, the greater the success of the plant species

Plants develop strategies to cope with different light intensities - what might they have in areas of low light?

larger leaves

2 other strategies to cope with different light intensities?

may develop photosynthetic pigments that require less light or reproductive systems that operate only when light availability is at an optimum

What is the greatest effect of temperature on?

the enzyme controlling metabolic reactions

What will develop more rapidly in warmer temperatures (2)?

plants and ectothermic animals

Why are endothermic animals less affected by their external environment?

they control their internal temperature

What can changes in the temperature of an ecosystem trigger in animals (for example due to changing seasons - 2)?

migration in some species and hibernation in others

What can changes in the temperature of an ecosystem trigger in plants (for example due to changing seasons - 3)?

leaf-fall, dormancy, and flowering

What does lack of water lead to in most plant and animal populations?

stress, which, if severe, will lead to death

Why does a lack of water cause most plants to wilt?

water is required to keep cells turgid and so keep the plant upright

What else is water required for in plants?

photosynthesis

What plants have developed strategies to cope with water stress?

xerophytes

In aquatic systems why is it beneficial to have fast-flowing cold water?

contains high concentrations of oxygen

What happens in aquatic systems if the water becomes too warm or the flow rate is too slow?

the resulting drop in oxygen concentration can lead to the suffocation of aquatic organisms

Why is the water availability reduced in waterlogged soil?

in waterlogged soil the air spaces between soil particles are filled with water

Why do different soil types have an effect on the organisms that are able to survive in them?

different soil types have different particle sizes

The 3 main soil types?

clay, loam and sandy

Clay?

fine particles, easily waterlogged, and forms clumps when wet

Loam?

different-sized particles and it retains water but does not become waterlogged

Sandy?

coarse, well-separated particles that allow free draining - sandy soil does not retain water and is easily eroded