19- variation and natural selection Flashcards Preview

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Flashcards in 19- variation and natural selection Deck (13)
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1

variation

differences between individuals of the same species

2

phenotypic variation

the differences between the features of different individuals.

3

genetic variation

the differences between individuals in their genotype

4

continuous variation

result of range of phenotypes between two extremes
eg; height, weight

5

discontinuous variation

definite fixed number of phenotypes
eg; blood groups, eye color, tongue rolling

6

mutation

genetic change in the base sequence of DNA, causing variation, and is way new alleles are formed

7

causes of mutation

1- ionizing raditation eg; x-rays
2- mutagenic substances eg; tobacco
3- heavy metals eg; lead, mercury

8

types of mutation

1- chromosome mutation eg; downs syndrome
2- genetic mutation eg; sickle cell anemia

9

symptoms of sickle cell anemia

- tired, shortness of breath
- heart palpitation
- limb swells

10

natural selection

When organisms are well adapted & survive in a habitat because of variation

11

evolution

The change in adaptive features of a population over time as a result of natural selection.

12

process of adaptation

The process resulting from natural selection by which populations become more suited to their environment over many generations.

13

artificial selection

When humans choose the best parents with best features to breed, generation after generation. Then these features become most common.