Replication, Variation, and Selection

Question 1

What did Charles and Alfred propose in the 19 century

Answer 1

In the mid 19th century both Charles Darwin and Alfred Russel Wallace described a mechanism for “the change in the average value of a (genetically based) characteristic over time” aka evolution

Question 2

What four processes can result in evolution

Answer 2

• natural selection
• mutation
• gene flow
• genetic drift

Question 3

What led to the writing of the origin of species

Answer 3

Charles Darwin spent 5 years travelling the world and observed a variety of organisms that lead him to write the origin of species

Question 4

What is Homology

Answer 4

1. Homology
   - similar anatomical structures and development are shared amongst related organisms
   - Ex. forearm bones in mammals are homologous, the same bones used for the leg of a dog, wing of a bat, and arm of a human

Question 5

What does the fossil record show

Answer 5

1. Fossil record
   - extinct forms have similarities to modern organisms
   - the closer in time = closer in appearance

Question 6

What is artificial selection

Answer 6

• human’s selecting for variations in domestic animals lead to the accumulation of selected changes
• this is how a wolf can be turned into a pug

Question 7

explain the struggle to exist

Answer 7

1. the struggle to exist
   - there are not enough resources for all organisms to survive
   - the organisms best suited will survive and reproduce

Question 8

Explain Biogeography

Answer 8

1. Biogeography
   - similar species often occur in close geographic regions
   - closer in space = closer in form

Question 9

What do descent with modification and natural selection explain

Answer 9

descent with modifications explains the patterns of similarity (in space and time)

and natural selection explains traits making an organism suited to their environment

Question 10

What 3 observations explain natural selection

Answer 10

1. the struggle for existance

competition exists within a population for survival and reproduction

1. variation in characteristics

within a population traits vary between individuals

some traits make an organism more suited for survival and reproduction

1. inheritance of characteristics (genetics)

traits are to some degree passed on to offspring

Question 11

Does Natural selection = evolution

Answer 11

Note: natural selection does not equal evolution

it is only one of four forces that can cause evolution, it is however the one that explains how organisms become adapted to their environment

Question 12

What is fitness

Answer 12

Fitness = the number of offspring produced over a lifetime

this is more important than individual survival

Survival of the fittest is therefor a contradiction

Question 13

What two reproduction processes produce daughter cells

Answer 13

Mitosis is how some eukaryotes reproduce

Binary fission is how bacteria reproduce

both result in identical “daughter cells”

Question 14

What types of chromosomes do diploid cells have

Answer 14

Homologous chromosomes = matching chromosomes

1 from mom, 1 from dad

Question 15

What are sister chromatids

Answer 15

sister chromatids = duplicated parts which make up a chromosome

Question 16

What is the policy formula

Answer 16

Ploidy formula: 2n = 46

indicated diploidia → 2n = 46 ←total # of chromosomes

Question 17

what does mitosis do

Answer 17

mitosis is used fro the growth of an individual animal, plant, or fungus

Question 18

why did organisms evolve to be multicellular

Answer 18

multicellularity can lead to bigger, more distinct organisms, which might be more fit

Question 19

What is a general definition for an individual

Answer 19

“one genome in one body”

1 bacteria or 1 human vs a colony of bacteria with multiple genomes

Question 20

what are phenotypes

Answer 20

Variation in characteristics = variation in phenotypes

a phenotype is an exposed characteristics, not the genes but the part that you can see, touch, etc

Question 21

What is selection based on

Answer 21

Selection is based on phenotypes, when 1 phenotype is more able to survive and reproduce

Selection is synonymous with when phenotypical differences directly determine success in replication and reproduction

Question 22

how do genotypes play into selection

Answer 22

Phenotypes is the genotypes + many non genetic factors resulting in a characteristic

IF the advantaged characteristic is due to genetic differences and not other factors, that characteristic will be more present in the next generation