Ecology Flashcards
Define habitat:
The environment in which and organism lives.
Define population:
The total number of organisms of the same species living in the same geographical area.
Define ecosystem:
Both the biotic and abiotic parts of an environment and how they interact.
Define community:
The populations of all of the different species that live in the same habitat.
What do plants compete for?
Light
Space
Water
Mineral ions in the soil
What do animals compete for?
Food
Water
Mating partners
Territory
Define interdependance:
All of the different species in a community depend on each other for food.
Define a stable community:
The populations of the different species in a community remain fairly constant.
Define a stable community:
The populations of the different species in a community remain fairly constant.
List four biotic factors:
Availability for food
Arrival of a new predator- this causes the population of the prey species to fall. Can also affect existing predators if they are competing for the same prey.
Competition between species can lead to extinction as numbers are no longer sufficient to breed.
New pathogens- this can wipe out a population of species.
List seven abiotic factors:
Light intensity:
If it is low, rate of photosynthesis falls and plants grow more slowly. Animals will have less food.
Temperature:
If the temperature of an environment changes then this could cause the distribution of species to change.
Water:
Both animals and plants need it to survive.
pH and mineral content of soil:
Many plants cannot grow on soil which is too acidic or too alkaline.
Plants also need minerals such as nitrates to make amino acids for proteins.
Wind intensity and direction:
Strong winds blowing from the sea can cause plants to lose water.
Carbon dioxide and oxygen:
If levels of CO2 fall, then rate of photosynthesis decreases.
Oxygen is needed for aerobic respiration.
The level if dissolved oxygen in water can fall, eg on hot days. This is harmful to aquatic organisms.
Food chains
Producer (green plant)
This is important because they synthesise important molecules.
Molecules made from photosynthesis such as glucose are called biomass. This passes down the food chain to the other organisms.
Primary consumers eat the producers. (prey)
Secondary consumers eat the primary consumers. (predator)
Tertiary consumers eat the secondary consumers.
Describe the populations of predators and prey in a community.
The numbers of predator and prey rise and fall in cycles.
If there is more producer, the populations of prey increase as they have more food.
Now the predators have more prey to kill and eat, so the predator population also increases.
However this means more prey is eaten, so the prey population decreases.
Now the predators have less prey to kill and eat, so their population also falls.
Now more prey survive and reproduce- population increases again.
