Ecosystems Flashcards
What is ecology?
Name given to the study of the relationships between organisms and their environments
What is an ecosystem?
A defined area where all the living organisms interact with one another, and also the physical factors present in that area. Ecosystems vary in size, from a tiny bacteria colony to the entire biosphere of the earth
What does dynamic mean in terms of ecosystems
They are constantly changing
What 2 factors affect ecosystems
Biotic factors - the living factors. E.g. in a forest, the presence of shrews and hedgehogs are biotic factors, as is the size of their populations. Competition for a food source is also biotic factor
Abiotic factors: the non living or physical factors like the amount of rainfall, temperature, pH…
What are biotic factors
Any interaction between organisms that are living or have once lived. These interactions include competition, either within or between a population. Competition included competing for things like food or space or even breeding parters
Role of light on ecosystem (abiotic factor)
Most plants are affected by light availability as it is required for photosynthesis. Most of the time, the greater the availability of light, the greater the success of the plant species
Sometimes plants develop strategies to cope with different light intensities: for example in low areas of light, they may have larger leaves. They may also develop photosynthetic pigments that require less light, or reproductive systems that operate only when light availability is at an optimum.
Temperature as an abiotic factor?
Temperature mainly affects the enzymes controlling metabolic reactions. Plants will grow more quickly in warmer temperatures as will ectothermic animals (Endothermic animals that control their internal temperature so are less affected by the external environment). Changes in temperature of an ecosystem due to season changes, can trigger migration in some animal species and hibernation in others. In plants in can trigger Leaf fall, dormancy and flowering
Water availability as an abiotic factor
In both plants and animals, the lack of water leads to water stress. If this is server, it will lead to death.
Lack of water causes plants to wilt as plants need water to keep turgid and therefore upright. It’s also needed for photosynthesis. Cacti are xerophytes with adaptations to cope with water stress.
Oxygen availability as an abiotic factor?
In aquatic ecosystems, it is necessary to have fast flowing cold water as it has high concentrations of oxygen. If water warms, or the flow rate slows, the drop in oxygen concentration can lead to suffocation of aquatic yutes. In waterlogged soil, the airspace’s between the soil particles are filled with water, reducing oxygen availability for plants
Edaphic (soil) factor as an abiotic factor
Different soil types have different particle sizes, having an effect on the organisms that are able to survive in them. Three main soil types:
- clay: has fine particles, easily waterlogged and forms clumps when wet
- loam: this has different sized particles, retains water but does not become waterlogged
- sandy: this has coarse, well separated particles that allow free draining - sandy soil does not retain water and is easily eroded
