Chapter 19: Populations in ecosystems Flashcards
Define the term ‘habitat’.
The place where an organism lives
Define the term ‘population’.
All the organisms of one species in a habitat
Define the term ‘community’.
Populations of different species in a habitat make up a community
Define the term ‘ecosystem’.
A community, plus all the non-living abiotic conditions in the area. Ecosystems can be large or small.
Define the term ‘abiotic conditions’.
The non-living features of the ecosystem
e.g.
temperature
water
Define the term ‘biotic conditions’.
The living features of the ecosystem
e.g.
predators
food
Define the term ‘niche’.
The role of a species within its habitat
What it eats, when and when it feeds
Define the term ‘adaptation’.
A feature that members of a species have that increase their chances of survival and reproduction
What is succession?
Succession is the process by which an ecosystem changes over time
Succession is also the gradual replacement of communities of animals and plants by other usually more varied communities
Describe what happens in primary succession.
bare rock
- inorganic surface
- harsh conditions + low species diversity
pioneer species
- weathering of rock produces soil
- humus first
- soil
- other species establish root systems
- action of roots + humus formed when species die
- more material added to soil
more nutrients and water retained
- less hardy species can survive
- gradually larger plants can be supported
- diversity increases
climax community reached
- biodiversity and range of species generally constant
- self-sustaining
- most productive group of organisms an environment can support
Describe what happens in secondary succession.
…
What is a pioneer species?
The first species to colonise an area
such as lichens mosses and algae
What is a climax community?
A climax community is the largest most complex community of plants and animals an ecosystem can support
It describes the last stage in succession
The state where the ecosystem is in a steady state
What is primary succession?
Primary succession refers to when bare rock or other barren land is first colonised
Land is newly formed or exposed containing no soil or organic materials for growth
What is the difference between primary succession and secondary succession?
Primary = barren land such as bare rock - no soil or organic material
volcanic eruption
landslide
Secondary succession = lands has been cleared e.g. forest fire, human activity but soil remains
