Bio Topic 4: Adaptation

Define population
A group of interbreeding individuals of the same species.
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Define community
All the living organisms in an area
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Define niche
The way an organism exploits its environment
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Why would species be in competition with each other?
Because they occupy the same niche. Ie. they have exactly the same role in their environment maybe same food source or shelter site so will be in direct competition with each other for survival.
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What is the difference between intraspecific and interspecific competition
Interspecific competition is between individuals of a different species while intraspecific competition is between the same species.
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Define adaptation
A trait that makes an organisms suited to its environment
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What is a behavioural adaptation? Give 2 examples.
Any action by an organism that helps them survive or reproduce. An agouti bring Brazil nuts helps them survive by providing a future food source. Plants turning their leaves towards the sunlight.
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What is a physiological adaptation? Give an example.
Features of the internal working of an organism that help them survive or reproduce. Thermophilic bacteria have high heat tolerance by having heat-stable enzymes allowing them to live in extreme conditions like hot springs/ thermal vents in oceans.
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What is an anatomical adaptation? Give an example.
Structures we can see through observation or dissection of an organism. Bumble bees show adaptations by different species having different tongue lengths that are specialised to feed from specific species of flowers.
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Define co-adapdation
the process by which 2 or more species, traits, genes or organs undergo adaptation as a group.
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When does co-adaptation occur?
When 2 or more characteristics undergo natural selection in response to the same selective pressure.
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Evolution: Observation 1
Individuals within a population have a great reproductive potential.
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Evolution: Deduction 1
Continous competition occurs between species b/c a habitat can only support so many individuals so there's a struggle for existence in a population & some individuals don't survive or reproduce. This limits the reproduction potential.
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Evolution: Observation 2
No. of individuals in a population remain the same but may fluctuate around a mean value.
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Evolution: Observation 3
Variation exists in all populations.
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Evolution: Deduction 2
Individuals w. adaptations that make them best suited to their environment have a selective advantage in the 'struggle for existence.'
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Define Evolution.
A change in allele frequency in a population over time
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What is the trait distribution if no selective pressure is present?
A bell shaped curve, there'd be variation with most individuals showing the mean of the trait.
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What is stabilising selection? Give an example.
Selective pressures select against the 2 extremes of the trait. Plant height: plant too short won't get sunlight and plant too tall more susceptible to wind damage so no. of medium heigh plants increase.
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What is directional selection? Give an example
One extreme of the trait is selected against so the population's trait distribution moves towards the opposite extreme. Selectional pressure selected against giraffes with short necks as they couldn't reach the leaves so longer necks favoured.
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What is disruptive selection?
Selectional pressure acts against individuals in the middle of the trait distribution. If small, medium and tall plant each pollinated by specific bee, and then medium plant pollinator disappeared, medium heigh plants would be selected against.
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How does speciation occur?
When 2 populations are spit into2 sub populations and isolated from each other, there's no gene flow between them so they can evolve into 2 separate species.
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What is a gene pool?
A gene pool consists of all the alleles of all the genes present in a population
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Why can a population never be perfectly adapted to their environment ?
Because there's a time gap between the change in the environment and the individuals ability to adapt via natural selection.
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What are 3 conditions that affect the ability of a population to adapt to new conditions?
1. Strength of the selectional pressure. 2. Size of the gene pool. 3. Reproductive rate of the organism.
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Other cards in this set

Card 2


Define community


All the living organisms in an area

Card 3


Define niche


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Card 4


Why would species be in competition with each other?


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Card 5


What is the difference between intraspecific and interspecific competition


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