Biology topic 4

What is a community?
A collection of the various populations in a habitat.
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What is a behavioral adaptation?
Any actions by an organism that help them to surive or reproduce.
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What is a physiological adaptation?
The internal workings of an organism that helps them survive or reproduce.
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What is a anatomical adaptation?
Structures in an organism that we observe or can see when they are dissected which help them to survive or reproduce.
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What is co-adaptation?
When two species become dependent on one another.
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Describe the process of evolution.
A population has natural genetic variation, change in environment causes change in selection pressure, a particular allele now becomes favourable, those with the allele are more likely to surivive and pass the allele on. The freq of it increases.
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What three factors affect the ability of an organism to adapt?
Size of gene pool, strength of selection pressure, reproductive rate.
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Name the kingdoms.
Animals, plants, fungi. protoctista (eukaryotes), prokaryotes (bacteria). Recently the kingsom chromista has been created with motile cells with flagella (they are not bacteria)
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What is convergent evolution?
Unrelated organisms evolving to prdouce similar phenotypes. e..g. sharks and dolphins. This is because they share the same environment.
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Name sources of genetic variation?
Mutations, independent assortment, crossing over, fertilisation.
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What is species richness?
The number of species in a given area.
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What does it mean when a community has a high evenness?
The number of each species is similar. There is no dominant species.
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Name structures unique to a plant cell.
plasmodesmata, pits, amyloplast (startch grains), chloroplasts, tonoplast, middle lamella.
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What is the glue which holds cellulose microfibrils together made of?
Hemicellulose, pectins. These are both polysaccarides.
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Where does the energy required to move water in the xylem come from?
The sun as it evapourates water creating a transpiration stream.
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What is the difference between cohesion and adhesion?
Cohesion is between water molecules while adhesion is between water molecules and the cell wall.
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Describe the different effects of ion deficiencies?
Lack of magnesium produces yellow leaves as it is in chlorophyll, lack of nitrogen causes yellow leaves as it is also in chlorophyll, lack of calcium causes stunted growth as it makes up the middle lamella.
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What is the movement of organic products in plants called?
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Describe the process of translocation?
Solutes are actively loaded into the phloem from transfer cells, This increases solute pressure so water moves into the phloem from the xylem. This increases the hydrostatic pressure so the water moves down the concentration gradient.
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What is the process which extracts plant fibres known as?
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Describe the steps Wethering took to test his drug.
Tested the drug on affected patients, measured side effects, tried to obtain the right dose, published results.
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Describe the steps in modern drug testing.
Active ingredient found, variations of the chemical structure made, tested on animals and tissue cultures for saftey and effectiveness. Tested on health people for side effect, tested on a small group of affected people, tested on a large group.
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Describe the structure of a seed.
cotyledon (food stored in the seed leaves), endosperm (food source), plumle (young shoot), radicle (young root), testa (seed coat, lignified)
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What are the aims of a breeding program?
Increase the number of individuals, maintain genetic diversity, reintroduce members of the species to the wild.
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What is genetic drfit?
In a small populaton some of the alleles may not get passed on to offspring based on chance. This leads to a decrease in genetic diversity.
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What is inbreeding depression?
When closely related individuals mate the frequency of homozygous genotypes increases. This means the number of homozygous recessive members of the population increases which can have negative effects.
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Card 2


What is a behavioral adaptation?


Any actions by an organism that help them to surive or reproduce.

Card 3


What is a physiological adaptation?


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Card 4


What is a anatomical adaptation?


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Card 5


What is co-adaptation?


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