7C Populations in Ecosystems Flashcards
What is a habitat?
The place where an organism lives
E.g. a rocky shore or a field
What is a population?
All the organisms of one species in a habitat
What is a community?
Populations of different species in a habitat make up a community
What is an ecosystem?
A community, plus all the non-living (abiotic) conditions in the area in which it lives
Ecosystems can be small e.g. a pond, or large e.g. an entire ocean
What are abiotic conditions?
The non-living features of the ecosystem
e.g. temp and availability of water
What are biotic conditions?
The living features of the ecosystem
e.g. the presence of predators or food
What is a niche?
The role of a species within its habitat
e.g. what it eats, where and when it feeds
What is an adaption?
A feature that members of a species have that increased their chance of survival & reproduction
e.g. giraffes have long necks that help them to reach vegetation that’s up high - this increased their chances of survival when food is scarce
What are the two types of niche a species can have?
Biotic interactions - e.g. the organism eats, and those it’s eaten by
Abiotic interactions - e.g. the oxygen an organism breathes in, and the CO2 it breathes out
How many species can have the same niche?
A niche can only be occupied by one species
Every species has its own unique niche
Why can two species look like they have the same niche?
They may both be eaten by the same species but they’ll be slight differences between them - ie variations in what they eat
What happens if two species try to occupy the same niche?
They will compete with each other
One species will be more successful than the other until only one species is left
Give two example of niches
- The common pipistrelle bat
- Soprano pipistrelle bat
What is the difference in the niches of the come on pipistrelle bat and the soprano pipistrelle bat?
Common pipi lives in Britain on farmland, open woodland, hedgerows & urban areas - feeds by flying & catching insects using echolocation at freq 45kHz
Soprano pipi lives in Britain woodland areas, close to lakes or rivers - feeds by flying & catching insects using echolocation at freq 55kHz
Do organisms adapt to biotic or abiotic conditions?
Both
Why do organisms adapt?
It increases the organisms chance of survival & reproduction
What types of adaptions can organisms make?
- Physiological (processes inside their body)
- Behavioural (the way an organism acts)
- Anatomical (structural features)
Why are organisms that have adapted more likely to survive?
Their adaptions make them more likely to survive, reproduce and pass on the alleles for their adaptions become more in the population
What is succesion?
It is the process in which an ecosystem changes over time
What is meant by the phrase of “ecosystems are dynamic”?
They’re constantly changing - through succession
How does succession affect the biotic & abiotic factors of the environment?
The biotic conditions change as the abiotic conditions change
What are the two types of succession?
- Primary succession
- Secondary succession
What is primary succession?
Happens on land that’s been newly formed or exposed
e.g. where a volcano has erupted to form new rock surface/where sea level has dropped exposing new area of land –> no soil/organic material to start with (e.g. just bare rock)
What is secondary succession?
Happens on land that’s been cleared of all the plants, but where soil remains
e.g. after a forest fire or where a forest has been cut down by humans
When & how does primary succession start?
It starts when species colonise a new land surface
Seeds & spores are blown by the wind % begin to grow
What is a pioneer species?
The first species to colonise an area
What are the abiotic conditions like in primary succesion and how do species survive in this?
They are hostile (harsh) e.g. no soil to retain water
Only pioneer species grow as they’re specially adapted to cope with harsh conditions e.g. marram grass can grow on sand dunes near the sea as it has deep roots to get water & can tolerate the salty environment
How does the poineer species affect the abiotic conditions in primary sucession?
The poineer species change the abiotic conditions
They die & microorganisms decompose the dead organic material (humus) –> this forms basic soil
How do pioneer species make conditions less hostile (go through the process)?
They die and decompose into soil - this changes the abiotic conditions
Basic soil helps retain water, new organisms can move in & grow –> these die & decompose, adding more organic material, making soil deeper & richer in minerals
Means larger plants like shrubs can start to grow in the deeper soil, which retains even more water
How do significant changes in abiotic conditions affect the species that live there?
New species may change the environment so it becomes less suitable for the previous species
e.g. sand sedge stabilises sand through the growth of rhizomes (underground stems) –> this makes the conditions less suitable for marram grass, which needs constant reburial by sand to frow healthily
How do niches affect ecosystems?
Every species is adapted to use an ecosystem in a way no other species can
e.g. giant anteaters can break into any nests & reach ants - they have claws to rip up the nest, long sticky tongue that can move rapidly in & out of it’s mouth to pick up ants
What conditions do animals adapt to in an environment?
The abiotic (eg how much water is available) conditions
The biotic (eg what predators there are) conditions
What is population size?
Total number of organisms of one species in a habitat
What is the carrying capacity?
Maximum stable population size of a species that an ecosystem can support
What factors affect the carrying capacity for a species?
- Biotic
- Abiotic
What conditions do animals have to adapt to?
- Biotic conditions (e.g. how much water is availble)
- Abiotic conditiond (e.g. what predators there are)
Give 3 examples of animals adapting to abiotic conditions
- Otters have webbed paws
- Seals have a thick layer of blubber
- Hedgehogs hibernate
How are otters webbed paws an abiotic adaption?
They mean they can both walk & swim effectively
This increases their chance of survival becuase htey can live & hunt both on land & in water
How are seaks having a thick layer of blubber an abiotic adaption?
This helps them to keep warmin the coldest seas
Increases their chance of survival because they can live in places where food is plentiful
How is hedgehogs hibernating an abiotic adaption?
They lower their rate of metabolism over winter
This increases their chance of survival becuase they can conserve energy during the coldest months
Give 3 examples of animals adapting to biotic conditions
- Sea otters using rocks to open shellfish & clams
- Male frogs produce mating calls to attract females
- Some bacteria produce antibodies
How is sea otters using rocks to open shellfish & clams biotic adaptions?
This increases their chance of survival because it gives them acess to another source of food
How is male frogs using mating calls a biotic adaption?
They use the mating calls to attract women
This makes sure they attract a mate of the same species
This increases their chance of reproduction by making successful mating more likely
How is some bacteria producing antibodies a biotic adaption?
These antibodies kill other species of bacteria in the same area
This increases their chance of survival because there’s less competetion for resources
How is secondary succession different from primary succession?
It happens in the same way as primary succession, but because there’s already a soil layer, succession starts at a later stage
Pioneer species in secondary succession are larger plants e.g. shrubs
What is the final stage of succession called?
The climax community
What is the climax community?
They’re the final species that arrive
The ecosystem is supporting is supporting the largest & most complex community of plants & animals it can - it won’t change much more, it’s in a steady state
What decides what makes the climax community?
It depends on what the climate is like in the ecosystem
The climax community for a particular climate is called its climatic climax
Give some examples of how the climate will affect the climatic climax species?
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