Classification and Evolution Flashcards

Question

How can meiosis and sexual reproduction lead to variation

Answer 1

Alleles: can inherit different combinations Mutations: changes in DNA, in in somatic cell only changes individual, if in gametes can be inherited Meiosis: independent assortment, crossing over Sexual reproduction: no two gametes the same so not identical to each other, only half from each parent so not identical to either parent

Answer 2

Plants: light intensity, water content of soil, mineral concentration in soil, wind exposure to wind, height Animals: flamingo turn pink on shrimp diet

Answer 3

Having a genotype that us not expressed due to interaction with the environment

Answer 4

An individual's observable traits, such as height, eye colour and blood type

Answer 5

All of the alleles that an organism carries on its chromosomes

Answer 6

Regulated by more than one gene, and is influenced by the environment. This type of variation is usually presented as a line graph or histogram

Answer 7

Regulated by a single gene, not influenced by any environmental factors. Presented on a bar or pie chart

Answer 8

Forms a bell shaped curve Normal distribution curve Mean, mode, median at same point 50% of values below the mean, 50% above Most values close to mean Number of individuals at extremes are low Spread of data can be determined using standard deviation

Answer 9

Differences between individuals

Answer 10

Variation caused by possessing a different combination of alleles

Answer 11

Variation caused by response to environmental factors

Answer 12

A variation in a characteristic that increases an organisms chance of survival and reproduction

Answer 13

Anatomical: physical features (internal and external) Behavioural: the way an organism acts (learned or inherited) Physiological: processes talking place inside an organism (biochemistry)

Answer 14

Plant: plants that flower at night to be pollinated by night time insects Animal: grooming

Answer 15

Plant: tree roots longer when water table lower Animal: Darwins finches - different shaped beaks

Answer 16

Plants: plants that use C4 photosynthesis which avoids photorespiration and conserves water by enabling stomata to be closed Animal: fewer sweat glands in desert animals

Answer 17

Leaf rolled longitudinally, air trapped inside, becomes humid, reduces water loss. Can coil more tightly in very dry conditions Thick waxy cuticle on outer side of leaf, reduces evaporation Stomata protected by enclosed air space as on inner side of rolled leaf Spongy mesophyll is very dense, few air spaces, less surface area for evaporation of water Stomata in pits on lower epidermis, folded and covered in hairs, helps recude air movement and loss of water vapour

Answer 18

Adaptations that perform the same function but have a different genetic origin

Answer 19

Appear different but have same underlying structure, in different species, likely evolved from a common ancestor

Answer 20

Genetic variation exists between individuals in a population. Some individuals will be more likely to survive (e.g. by being better at fighting disease) than others. Individuals that are better at surviving than others have a selective advantage Individuals with a selective advantage are more likely to survive to reproduce than others. This means that the genes of an individual with a selective advantage are more likely to be passed onto offspring than the genes of an individual without a selective advantage Individuals with a selective advantage are more likely to pass on their beneficial alleles than other individuals. The next generation is more likely to have alleles that provide a selective advantage than alleles that do not. This generation is also more likely to survive to reproduce and pass on their genes. This causes the alleles that provide a selective advantage to increase in frequency in the population.