Populations In Ecosystems Flashcards
Niche
The role of a species within its habitat
Abiotic
The non-living features of the ecosystem
Biotic
The living features of the ecosystem
Ecosystem
A community with all the abiotic conditions in the area in which it lives
The niche a species occupies within its habitat includes:
It’s biotic interactions - what it eats etc
It’s abiotic interactions - the oxygen ur breaths in etc
What happens if two species try to occupy the same niche?
They will compete with eachother - one species will be more successful than the other so only one of the species is left.
What are adaptations?
Features that increase an organism’s chance of survival and reproduction.
Adaptations can be:
Physiological
Behavioural
Anatomical
Organisms with better adaptations are more likely to…
Survive, reprice and pass on their alleles for their adaptations - adaptations become more common - natural selection.
Give 2 examples of adaptations to Abiotic conditions:
- seals have a thick layer or fat to keep them warm.
- hedgehogs hibernate to lower their rate of metabolism over winter.
Give 2 examples of adaptations to Biotic conditions:
- some bacteria produce antibiotics to kill other species of bacteria.
- Male frogs have mating calls to attract females.
What is the population size?
The total number of organisms of one species in a habitat.
What is the carrying capacity?
The maximum stable population size of a species than an ecosystem can support.
What happens when abiotic conditions aren’t ideal for a species?
The organisms can’t grow as fast or reproduce as successfully.
What is Interspecific competition?
When organisms of different species compete with eachother for the same resources.
What does interspecific competition do to the amount of resources?
Limits them to both the populations - so both populations will be limited and decrease in size.
What happens if two species are competing but one is better adapted to its surroundings?
The less well adapted species is likely to be out-competed.
What is Intraspecific competition?
When organisms of the same species compete with eachother for the same resources.
What happens in Intraspecific competition?
- population of a species increases when resources are plentiful - as the population grows, more competition.
- these resources become limited so population begins to decline.
- smaller population means less competition so population grows again.
Predation is where…
An organism kills and eats another organism.
Describe a predator-prey cycle:
- the prey increases, more food so predators increase.
- predator increases, less prey as more is eaten so prey decreases.
- less food for predators so their population decreases and so on.
What is Succession?
Succession is the process by which an ecosystem changes over time. The biotic conditions change as the abiotic conditions change.
What is primary succession?
This happens on land that’s been newly formed or exposed e.g. where a volcano has erupted to form a new rock surface - no soil or organic material.
What is secondary succession?
This happens on land that’s been cleared of all the plants but where the soil remains e.g. forest where trees have been cut down.
Primary succession starts when…
A new species colonised a new land surface - this species is known as the pioneer species.
What happens once the pioneer species has came?
- abiotic conditions are harsh so the pioneer species is adapted to it, once they die they change the abiotic conditions - forming a basic soil after they are decomposed.
- conditions are less hostile meaning new organisms with diff adaptations can form - they die and soil becomes deeper and richer so larger plants can grow.
- this means it becomes less suitable for previous species.
Secondary succession happens when…
There is already a soil layer - but the pioneer species are larger plants.
Diff plants and animals that are better adapted for the improved conditions move in and out compete animals and plans already there - become dominant.
- as it goes in, ecosystem becomes more complex and biodiversity increases.
What is the final stage of succession?
Climax community - when the ecosystem is supporting the largest and most complex community of plants and animals it can - it won’t change much as its already steady.
Different species have different…
Climax communities - e.g. some species need a temperate climate while others need a polar climate.
Describe the Mark-Release-Capture:
- capture a sample of species (counted)
- mark them in a harmless way.
- release back into habitat and wait for them to integrate again.
- take a second sample and count how many are marked.
Describe how you would use Quadrats:
- use a random number generator to get a set of co-ordinates for two diff areas.
- place quadrats in those places and count how many species are in them.
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