5 mechanisms

Question 1

whats comparative anatomy

Answer 1

Study of similarities and differences in anatomy between species

Homologous: Similar structure, same common ancestor, may hv diff func

Analogous: Structures have similar funcs, not same common ancestor

Vestigial: Homologous characteristics that have lost all of its original func thro evoloution

Question 2

Whats biochemical analysis?

Answer 2

determines how closely related 2 organisms are by comparing DNA and proteins, use DNA barcoding

Question 3

5 mechanisms

Answer 3

Genetic drift, Non random mating, mutations, gene flow, natural selection

Question 4

Mutations

Answer 4

Changes that randomly occur in DNA, heritable, only source of new alleles

Question 5

3 types of mutations, describe them

Answer 5

Neutral: affects the non-coding part of genetic material, do not benefit or harm
(attached earlobes v not attached)

Beneficial: rare, environment selects them, helps them live longer and reproduce. Alleles accumulate overtime
(bacteria resistance to antibiotics)

Harmful: common, environment selects against them, alleles that result from them are rare (cystic fibrosis)

Question 6

Natural selection

Answer 6

Organisms with advantageous heritable traits are selected for, survive and reproduce passing their traits to their offsprings

Question 7

Selective pressure

Answer 7

Selects for or against specific traits that allow organisms to survive and reproduce viable offsprings

Question 8

what was darwins conclusions

Answer 8

organisms evolve overtime, change occurs gradually, organisms come from a common ancestry, species multiply and evolve into new species, surviving organisms have traits adaptive to their environment and pass them on

Question 9

3 types of natty selection

Answer 9

Directional: results in a shift in one extreme, eg darker phenotype

Disruptive: Selects for both extremes, removes common.
EG finches w small and large beaks, large eats hard and small eats small/soft seeds, middle size outcompeted

Stabilizing: Favours intermediate, against extremes, eg, human baby size (medium)

Question 10

2 types of Non- random mating

Answer 10

Mating which is selected, but not artificially

Inbreeding and prefered phenotypes

Question 11

Inbreeding

Answer 11

closely related individuals breed together, usually live closer in proximity,

Homozygous genotype increases, decreases genetic diversity = susceptible to disorder

Question 12

Prefered phenotypes

Answer 12

Selecting a mate based on physical and behavioural traits (phenotypes)

Assortative mating: when individs mate w partners that r like themselves in certain characteristics

Disassortative mating: phonetically dissimilar organisms mate

Question 13

Does non-random cause microevoloution

Answer 13

No, contributes to natural selection, but no micro by itself

does not alter allele frequencies, however increases number of homozygous indivds

Question 14

Sexual selection

Answer 14

Certain characteristics are actively sought out by one sex (female usually)

Males usually have to perform rituals to impress female peacocks, feathers bright colours etc

Females mate w strong caribious

Question 15

Sexual dimorphism

Answer 15

A marked diff btw males and females ( colour diff)

Question 16

Sexual selection v natural selection

Answer 16

both focus on fitness: pass on genetic material to offspring, produce offsprings

NS: focuses on survival and reproductive success

SS: just reproductive success, dc abt surviving longer

Question 17

Prefered pheno v sexual selection

Answer 17

PP: does not change allele frequency
SS: does change allele frequency bc specific indivds r mating

Question 18

Genetic drift

Answer 18

Change in gene or allele frequency in a small population, lost at random/by chance

2 types, bottleneck, founders affect

Question 19

Bottleneck affect

Answer 19

Large temporary reduction in population, results in significant genetic drift

By chance, usually natural disaster, only small number of allelles survive

Question 20

Founders Effect

Answer 20

By chance, small number of dispersed individuals establish a new population far from the original one

Limited number of alleles present, eg, gingers leave then gingers present

Question 21

Gene flow

Answer 21

Movement (immigration) of alleles from one population to another

Needs a fertile individual to move, alters allele frequency, increases genetic diveristy