Population in ecosystems Flashcards
(38 cards)
Define species
Group of similar organisms that reproduce to produce fertile offspring
Define population
All of the individuals of a species in a specific place at the same time
Define community
All of the populations of different species in a particular place at the same time
Why can two species not occupy the same niche?
Competitive exclusion principle
What is the name given to the maximum size a population can become?
Carrying capacity
What is a limiting factor in terms of population?
A factor which would limit the growth of a population
Example of a limiting factor of a population
Nutrients
Mineral ions
Light
Temperature
Predators
Disease
What are abiotic limiting factors
Non-living factors
What are biotic limiting factors?
Living factors
Why might temperature limit a population?
Every organism has a optimum temperature. Too cold, enzymes work slowly, too hot enzymes denature
Why might light limit a population?
Ultimate energy source. Allows photosynthesis. More photosynthesis= more plants and therefore more organisms which follow in the food chain
Why is pH a limiting factor of population?
pH affects the activity of enzymes
Why might water and humidity limit a population?
Humidity affects transpiration. Few organisms survive when water is scarce
What are two types of competition?
Interspecific and intraspecific
Describe interspecific competition
When individuals of different species compete for resources
Describe intraspecific competition
Individuals of the same species compete for resources
If there is intraspecific competition and the environment stays constant, what will happen?
Competitive exclusion. One organism will be better suited to the environment so its population will increase, its competitors will decrease until extinction
What does the competitive exclusion principle mean for niches?
No two organisms occupy the same niche
What is a predator?
An organism which hunts and feeds on other animals
What is prey?
An animal which is hunted and eaten by a predator
Why do changes in conditions and number of predators affect evolution|?
Create a selection pressure so those best suited survive.
Two types of sampling
Random and systematic
What is used to sample systematically?
Belt transect
What are three factors too assess when using quadrats?
- Size of quadrat
- Number of quadrat
- Position of quadrat
