Evidence For Evolution

Question 1

The Fossil Record

Answer 1

• When fossils are arrayed in the order of their age, a progressive series of changes are seen
• Fossil records document the course of life through time

no outliers

Question 2

evidence of evolution

Answer 2

o Evolutionary change in body size, crown height, molar base expansion, and toe reduction

as you get bigger, you get less toes ie. horses and their hooves

Question 3

Transitional Fossils

Answer 3

from fishes –> land animals

Tiktaalik: intermediate between fish and land animals

Question 4

Molecular Record

Answer 4

• The longer organisms have been separated according to the fossil record, the more differences are seen in the structure of their DNA

Question 5

without errors

Answer 5

there would be no evolution

more mutations between species, the farther apart they in the fossil record

Question 6

silent mutations in a protein

Answer 6

don’t affect the amino acids and wont change the overall function of a protein

Question 7

Nonsynonymous (missense) substitutions

Answer 7

do change the amino acid sequence and are likely to have an effect (often deleterious) on protein function; such substitutions are targets for natural selection.

Question 8

cytochrome c

Answer 8

lack of variation across the sequences at positions 70-80 showing the similarity between organisms

suggests that this region is under strong stabilizing selection and that changing its amino acid sequence would impair the protein’s function

Question 9

Human Chromosome 2

Answer 9

great apes have 24 chromosomes

humans have 23 chromosomes

reasons we have 23 chromosomes is because great apes evolved and their two chromosomes became one chromosome aka Human chromosome 2

Question 10

SRGAP2

Answer 10

Humans have four different versions of SRGAP2

primates have just one.

was duplicated in the human lineage about 3.4 mya, resulting in SRGAP2A and SRGAP2B

Further duplications of SRGAP2B gave rise to SRGAP2C about 2.4 mya and to SRGAP2D about 1 mya.

Question 11

SRGAP2A

Answer 11

SRGAP2A, stimulates the maturation of dendritic spines

Question 12

SRGAP2C

Answer 12

promotes an increased number of immature spines

might have played a major part in the emergence of the Homo lineage 2-3 mya

This development might have contributed to the evolution of human cognitive abilities.

Question 13

SRGAP2 MUTATIONS

Answer 13

mutations of the gene in the brain’s neocortex led to complex thought

Question 14

Ostn genes

Answer 14

found in the muscles and bones of mammals

in humans its also found in neurons and provides clues to how humans evolved their cognitive abilities

Question 15

opsin gene

Answer 15

tuned to a specific wavelength of light that helps us see different colors

Humans, apes and Old World primates have 3 separate opsin genes involved in color vision.

Question 16

dichromat

Answer 16

see fewer than 20 color nuances

Question 17

trichromat

Answer 17

See between 20 and 32 color nuances

Question 18

tetrachromat

Answer 18

See between 32 and 39 colors nuances

Question 19

short wavelength opsin gene

Answer 19

found on chromosome 7

all primates have it

Question 20

medium and long opsin

Answer 20

found on the X chromosome

old world primates have medium and long=tetrochromatic

Question 21

New world monkeys

Answer 21

mutations in genes that discontinued monkeys from having both medium and long wavelength

female new world monkeys have the potential to be trichromatic because since the medium and long wavelength is found on the X chromosome

male new world monkeys are only dichromatic because they only have one X chromosome meaning they can only be MW or LW

Question 22

Homology vs Homoplasy

Answer 22

Homology is similarity due to common descent and homoplasy is similarity due to environment not common descent ie arctic: white fur

Question 23

structural homology

Answer 23

inherited similar structures from a common ancestor

Question 24

wings

Answer 24

between bats and birds

don’t have common ancestor but due to their environment they have wings

Question 25

convergent morphology

Answer 25

convergent evolution aka homoplasy

Similar anatomy evolved among lineages that independently adopted marine lifestyles

aka land animals became water animals and all developed fins

Question 26

Developmental Homology

Answer 26

Developmental similarities reflect descent from a common ancestor

Question 27

Genetic Toolkit

Answer 27

molecular factors that influence genes

DNA Replication, transcription, and translation

Question 28

Hox genes

Answer 28

affect body position

can reorder the way organs are developed throughout the body

Question 29

homeobox

Answer 29

All of the HOM and Hox genes share a 180-base-pair sequence

almost identical in insects and vertebrates

homology

Question 30

hom and hox genes are similar

Answer 30

they specify the locations of cells in embryos.

Question 31

Sonic hedgehog

Answer 31

prevents pythons from developing legs all the way

Question 32

prairie voles

Answer 32

monogamous
display extensive bonding behaviors after mating. These behaviors are mediated by peptides acting as intercellular signals.

When prairie voles mate specific peptides consisting of 9 amino acids are released; oxytocin in females, vasopressin in males.

receptors for oxytocin and vasopressin in prairie voles are highly concentrated in brain regions responsible for attachment

Question 33

montane and meadow voles

Answer 33

polygamous

there are far fewer receptors for these peptides, and as a result, fewer bonding and caring behaviors.

Question 34

vestigial structures

Answer 34

structures that you don’t need anymore

aka goosebumps, human tailbone

Question 35

analogous traits

Answer 35

similarities result from convergent evolution

Question 36

patterns of distribution

Answer 36

inhabitants of ocean islands resemble forms of the nearest mainland

Question 37

adaptive radiation

Answer 37

over time, the population diversifies into several distinct species on different islands

Question 38

biogeographical record

Answer 38

Darwin concluded:
Species arrive on islands by dispersing across the water

Dispersal from nearby areas is more likely than distant sources

Colonizers often evolve into many species
Marine species richness is greater around islands than terrestrial species richness on the islands because marine species are more successful at colonizing island habitats via the water than terrestrial species: no intermediary needed

After arriving at an island, species evolve, leading to the even greater species richness we see in marine species than in terrestrial species