19- variation and natural selection

Question 1

variation

Answer 1

differences between individuals of the same species

Question 2

phenotypic variation

Answer 2

the differences between the features of different individuals.

Question 3

genetic variation

Answer 3

the differences between individuals in their genotype

Question 4

continuous variation

Answer 4

result of range of phenotypes between two extremes

eg; height, weight

Question 5

discontinuous variation

Answer 5

definite fixed number of phenotypes

eg; blood groups, eye color, tongue rolling

Question 6

mutation

Answer 6

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

Question 7

causes of mutation

Answer 7

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

Question 8

types of mutation

Answer 8

1- chromosome mutation eg; downs syndrome

2- genetic mutation eg; sickle cell anemia

Question 9

symptoms of sickle cell anemia

Answer 9

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

Question 10

natural selection

Answer 10

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

Question 11

evolution

Answer 11

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

Question 12

process of adaptation

Answer 12

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

Question 13

artificial selection

Answer 13

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