Flashcards in Populations in Ecosystems Deck (45)
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Habitat?
place where an organism lives
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Population?
all organisms of one species in a habitat
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Community?
populations of different species in a habitat make up a community
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Ecosystem?
a community, plus all the abiotic conditions in the area in which it lives
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Abiotic conditions?
non-living features of an ecosystem e.g. temp, availability of water
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Biotic conditions?
living features of an ecosystem e.g. presence of predators or food
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Niche?
the role of a species within its habitat - includes its biotic interactions (organisms it eats, those its eaten by) and abiotic interactions (O2 it breathes, CO2 it breathes out)
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Adaptation?
a feature that members of a species have that increases their chance of survival and reproduction
e.g. giraffes have long necks to help them reach vegetation that's high up, increasing their chances of survival when food is scarce
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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
(every species has its own unique niche)
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What are physiological adaptations?
processes inside the body
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What are behavioural adaptations?
the way an organism acts
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What are anatomical adaptations?
structural features of the body
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What is natural selection?
organisms with better adaptations are more likely to survive, reproduce and pass on their alleles for their adaptations, so the adaptations become more common in the population
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3 examples of adaptations to abiotic conditions in an environment?
-Otters have webbed paws - they can walk on land and swim effectively, increasing their chances of survival because they can live and hunt both on land and in water
-Seal have a thick layer of blubber - helps keep them warm in the coldest seas, increasing chances of survival because they can live in places where food is plentiful
-Hedgehogs hibernate - they lower their rate of metabolism over the winter, increasing chances of survival because they can conserve energy during the coldest months
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3 examples of adaptations to biotic factors in an environment?
-Sea otters use rocks to smash open shellfish and clams, increasing chances of survival because it gives them access to another food source
-Male frogs produce mating calls to attract females, making sure they attract a mate of the same species, increasing chance of reproduction by making successful mating more likely
-Some bacteria produce antibiotics which kill other species of bacteria in the same area, increasing chances of survival because there's less competition for resources
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What is population size?
the total number of organisms of one species in a habitat
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What is the carrying capacity?
maximum stable population size of a species that an ecosystem can support (varies as a result of abiotic and biotic factors)
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What are examples of abiotic factors?
light, water, space, temp of surroundings, chemical composition of surroundings
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How is population size affected when temp of an mammal's surroundings is ideal?
ideal temp of surroundings for metabolic reactions to take place means they don't have to use up as much energy maintaining their body temp. So more energy can be used for growth and reproduction, so population size increases
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How is population size affected when temp of an mammal's surroundings is lower or higher than their optimum body temp?
they have to use a lot of energy to maintain the right body temp. So less energy available for growth and reproduction, so population size decreases
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What is interspecific competition?
competition between different species for the same resources
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Why would interspecific competition limit population sizes of both species?
if they share the same food source, there will be less available to both of them. Both populations are limited by a lower amount of food. They have less energy for growth and reproduction, so population sizes will be lower for both species
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What is the effect of interspecific competition if one species is better adapted?
the less well adapted species is likely to be out-competed - won't be able to exist alongside the better adapted species
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What is infraspecific competition?
competition between organisms of the same species for the same resources
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What is the effect of infraspecific competition on population size?
1. population of a species increases when resources are plentiful, as population increases, more organisms competing for same amount of food and space
2. resources (food and space) become limiting - isn't enough for all organisms, population starts to decline
3. smaller population means less competition for space and food, which is better for growth and reproduction - population starts to grow again
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What is predation?
an organism (predator) kills and eats another organism (prey)
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Why are population sizes of predators and prey interlinked?
as the population of one changes, it causes the other population to change
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Describe a predator-prey cycle.
1. as prey population increases, more food for predators, so predator population grows
2. as predator population increases, more prey is eaten, so prey population begins to fall
3. less food for predators, so predator population decreases and so on
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Why are predator-prey cycles usually more complicated?
there are other factors involved, like availability of food for prey. e.g. population of prey might initially decrease because there's too many of them for the amount of food available, this is then accelerated by predation
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