23.1- Ecosystems

Question 1

What is ecology?

Answer 1

The study of then relationships between organisms and their environment.
- essential to help scientists understand the interdependence of living organisms and ensure survival of biodiversity.

Question 2

What is an ecosystem?

Answer 2

An ecosystem is made up of all the living organisms that interact with one another in a defined area, and also the physical factors present.
- can vary drastically in size (from tiny bacterial colony to Earth!s entire biosphere)

Question 3

What factors affect ecosystems?

Answer 3

All ecosystems are dynamic (constantly changing). This is a result of the living organisms present and the environmental conditions.
Two main groups:
- biotic factors.
- abiotic factors.

Question 4

What are biotic factors?

Answer 4

The living factors. Often also refers to the interactions between living organisms.
Eg. Population size of an organism.
- competition (for food, territory, partners)
- disease

Question 5

What are abiotic factors?

Answer 5

The non-living / physical factors.

Eg. Light, temp, water/oxygen availability, soil factors.

Question 6

Effect of light on an ecosystem?

Answer 6

• most plants are directly affected by light as it is a requirement for photosynthesis.
  Greater the light availability = greater the success of a plant species.
• plants develop strategies to cope with certain light intensities. (Eg. Larger leaves, photosynthetic pigments).

Question 7

Effect of temperature on ecosystems?

Answer 7

• main effect is on the enzymes controlling metabolic reactions.
• plants and ectothermic animals develop more rapidly in warmer temperatures.
• changes in temperature of an ecosystem can trigger migration/hibernation in animal species or flowering/dormancy in plant species.

Question 8

Effect of water availability on ecosystems?

Answer 8

• a lack of water leads to water stress which can cause death if severe.
• in plants, it causes most to wilt as water is required to keep cells turgid. Required for photosynthesis.
• xerophytes have strategies to cope with water stress.

Question 9

Effect of oxygen availability on ecosystems?

Answer 9

In aquatic ecosystems, its beneficial to have fast-flowing cold water as it contains high concentrations of oxygen.
- if water becomes too warm/slow, the resulting drop of oxygen concentration can lead to suffocation of aquatic organisms.

Question 10

Effect of edaphic (soil) factors on ecosystems?

3 types

Answer 10

Different soil types have different particle sizes. This effects the organisms that are able to survive in them.
3 main soil types:
1. Clay- fine particles, easily waterlogged, and forms clumps when wet.
2. Loam- different sized particles, retains water but doesn’t become waterlogged.
3. Sandy- coarse, well-separated particles. These allow free draining. Doesn’t retain water, easily eroded.