Chapter 9 Powerpoint flashcards

Question 1

What is evolution?

Answer 1

The gradual changes in the characteristics of a species over many generations, resulting from changes in allele frequencies in a population’s gene pool

Question 2

Define gene pool

Answer 2

The sum of all alleles in given population at a particular time

Question 3

What are allele frequencies?

Answer 3

The proportion of each allele of a gene present in a population’s gene pool

Question 4

Name the two types of mutations

Answer 4

Gene mutation: Affects a single gene
Chromosomal mutation: Affects part or whole chromosomes

Question 5

What are mutagens? Give examples

Answer 5

Agents that increase the rate of mutations
e.g. mustard gas, UV light, x-rays

Question 6

Difference between somatic and germline mutations?

Answer 6

Somatic mutations occur in body cells and affect only the individual
Germline mutations occur in reproductive cells and can be inherited

Question 7

What is a point mutation?

Answer 7

A mutation involving the change of a single nucleotide (insertion, deletion or substitution)

Question 8

What is a frameshift mutation?

Answer 8

A mutation where bases are added or removed, shifting the reading frame of codons and altering all amino acids from that point

Question 9

Give two examples of conditions caused by gene mutations

Answer 9

-Duchenne muscular trophy
-Cystic fibrosis

Question 10

Give two examples of conditions caused by chromosomal mutations

Answer 10

-Down syndrome (trisomy 21)
-Turner syndrome (monosomy X)

Question 11

What is gene flow?

Answer 11

The movement of alleles from one population to another due to migration

Question 12

Give two types of barriers to gene flow

Answer 12

-Geographical (mountains, oceans, rivers)
-Sociocultural (religion, language)

Question 13

List the principles of natural selection

Answer 13

-Variation
-Overpopulation
-Competition
-Heritability
-Allele frequency

Question 14

What is a selective agent?

Answer 14

An environmental factor that influences which individuals survive and reproduce

Question 15

Define heterozygote advantage and give an example

Answer 15

-When a heterozygous individuals have a survival benefit over both homozygotes. Example: Sickle cell

Question 16

What is genetic drift?

Answer 16

A random, non-directional change in allele frequencies between generations

Question 17

What is the founder effect?

Answer 17

When a new population is established by a small group, leading to reduced genetic variation and different allele frequencies from the original frequencies

Question 18

What is the bottleneck effect?

Answer 18

A severe reduction in population size due to chance events, causing changes in allele frequencies

Question 19

Define speciation

Answer 19

The formation of new species due to reproductive isolation and genetic divergence

Question 20

What are the steps in speciation?

Answer 20

-Variation: There is variation between individuals of a species
-Isolation: Populations of the same species are isolated without gene flow
-Selection: Each population is subjected to different selective agents
-Speciation: The allele frequency changes until they become so different that the two groups are no longer able to interbreed