Populations Flashcards
Define the term population
All the organisms/ populations present in an habitat
Define the term community
All the organisms/ populations present in an habitat
Define the term ecosystem
the community and the non-living / abiotic components of the environment
Define the term niche
the role of the organism in its ecosystem
What are abiotic factors?
non living factors
What are biotic factors?
factors due to interactions of organisms, ie living factors
Give examples of abiotic factors
- soil type
- ph
- CO2 concentration
- temperature
- light intensity
- water availability
Give examples of biotic factors
- food availability
- predatation
- parasitism
- disease
- competition
What do plants compete for ?
light, water, minerals
What do animals compete for?
food, territory, mates, breeding sites
What are the two types of competition?
-interspecific competition
intraspecific competition
Define the term interspecific competition and give an example
competition between different species, eg. weeds and crop plants in a field competing for light and minerals
Give an example of an organisms niche
- feeding role
- abiotic conditions it lives in
- its philosophy
- behaviour
- reproduction method
Describe the relationship between the similarity of an organisms niche and the competition
the more similar the niches of two competitors, the greater the competition will be
Define the term intraspecific competition and give an example
this occurs between individuals of the same species for the same resource , eg, to sow seeds at increasing densities otherwise in identical pots
What actions can a farmer take to reduce the effect of intraspecific competition?
irrigate
add fertiliser to field, prevents mineral availability becoming a limiting factor
Describe a predator
an organism that hunts, kills and eats another, the prey .
What affect does a decline in prey numbers have on the predators?.
In response what will happen to the size of the prey population?
less food results in more intraspecific competition,
less reproduction,
increased morality so predator population decreases
fewer eaten,
more survive to breed,
so population inceases
Define the term carrying capacity
the maximum size that a population can remain sustainable in a particular habitat
What causes change in population size?
- the effect of abiotic factors
- interactions between organisms
What are autotrophs?
primary producers
What are heterotrophs?
`-primary consumers
- secondary consumers
- tertiary consumers
Give an example of a decomposer
barteria and fungi
What is a food chain ?
a series of trophic levels
A food chain usually has 4 or 5 trophic levels but rarely 6. why do u think this is so?
energy is lost at each trophic level therefore there is not enough energy at the end of the food chain to support further trophic levels
