Chapter Eight: Evolution Flashcards

Question

How did the giraffe "get" it's long neck?

Answer 1

Ancestral giraffes were all short-necked, although the length did vary between individuals. As population and competition increased, the talkers ones had a better chance of survival. Over time only long-necked ones increased and others were eliminated. NO ANIMALS NECK GREW LONGER, THE AVERAGE LENGTH OF THE NECK IN THE POPULATION INCREASED

Answer 2

At first, most were white, only some dark. White moths camouflaged with their environment and Dark's ones were easy prey. But with industrialization soot polluted the environment and made everything black. This meant dark moths were camouflaged and had the selective advantage. With time, dark ones replaced white ones. NO MOTH CHANGED COLOR, THE FREQUENCY FOR THE DARK ALLELE INCREASED

Answer 3

Antibiotics killed susceptible bacteria and the rest were resistant. THE ANTIBIOTIC DID NOT INDUCE MUTATIONS FOR RESISTANCE. The resistant survivors pass on the traits to make a population resistant

Answer 4

The AIDS virus has the ability to rapidly mutate and evolve and become resistant to drugs. Susceptible viruses become deactivated but the survivors create an entire population of resistant viruses.

Answer 5

The viruses evolve rapidly

Answer 6

Which phenotypes of a population are favoured

Answer 7

Eliminates the extremes (they just die) and favors more common intermediate forms

Answer 8

Increasing the no. of extreme types at tge expense of intermediate forms

Answer 9

Results from disruptive selection where in the short term 2 or more phenotypes coexist in a population

Answer 10

The formation of 2 entirely new species

Answer 11

With changing environmental conditions, one phenotype replaces another in the gene pool

Answer 12

- mutation - genetic drift - gene flow

Answer 13

Changes in genetic material and the raw material for evolutionary change

Answer 14

Single point mutation

Answer 15

Change in the gene pool due to CHANCE

Answer 16

When natural disasters reduce population size nonselectively, resulting in loss of genetic variation. The population becomes smaller and not representative of the original one. Certain alleles may under or over represented compared with the original population

Answer 17

When a small population breaks away from a larger one to colonize a new area, it is most likely not genetically representative of the original one, as rare alleles may be overrepresented (due to breeding in extreme isolation between close communities)

Answer 18

Movement of alleles into or out of a population, as a result of migration of fertile individuals or gametes

Answer 19

A stable, non-evolving population, that is, one in which allele frequency does not change in any course of time (eg 0.5 allele frequency for a trait, if population is not evolving, after 1000 years it will be 0.5)

Answer 20

Hardy-Weinberg Equilibrium

Answer 21

1. THE POPULATION MUST BE VERY LARGE 2. THE POPULATION MUST BE ISOLATED FROM OTHER POPULATIONS 3. THERE MUST BE NO MUTATIONS IN THE POPULATION 4. MATING MUST BE RANDOM 5. THERE MUST BE NO NATURAL SELECTION

Answer 22

1. THE POPULATION MUST BE VERY LARGE. Because in a small one the smallest change in the gene pool will have a major effect on in allelic frequency. If a large one the small change will be diluted and there will be no change in allelic frequency

Answer 23

2. THE POPULATION MUST BE ISOLATED FROM OTHER POPULATIONS. There should be no migration of organisms into and out of the gene pool because that would alter the allelic frequencies

Answer 24

3. THERE MUST BE NO MUTATIONS IN THE POPULATION. A mutation in the gene pool could alter the allelic frequency or introduce a new allele

Answer 25

4. MATING MUST BE RANDOM. If individuals select mates, they will be better fit and have a reproductive advantage and the population will evolve

Answer 26

5. THERE MUST BE NO NATURAL SELECTION. Because it causes changes in relative frequencies of alleles in a gene pool

Answer 27

To calculate frequency of an allele in a population

Answer 28

p+q=1 (p^2)+(2pq)+(q^2)=1 Where p is dominant and q is recessive

Answer 29

p^2=AA homozygous dominant 2pq=Aa hybrid q^2=aa homozygous recessive

Answer 30

A population whose members have the potential to interbreed in nature and produce fertile offspring

Answer 31

The groups are subjected to selective pressures in their environments. With time the groups would have changed so much that they would not interbreed when reintroduced

Answer 32

1) geographic isolation 2) polyploidy 3) habitat isolation 4) behavioral isolation 5) temporal isolation 6) reproductive isolation

Answer 33

When a species is separated by a natural barrier

Answer 34

A type of mutation caused by errors in meiosis, instead of being haploid/diploid they may be tetrapliod or even larger. Such polyploid organisms cannot breed with nonpolyploid ones

Answer 35

When two species live in the same area but encounter eachother rarely (ie land and water)

Answer 36

It occurs when animals become isolated due to some change in behavior by one group

Answer 37

It refers to time, such as as to when different organisms of one species sexually mature and become divided into 2 populations. (eg summer and winter of growing season)

Answer 38

Closely related species may not be able to mate because of anatomical incompatibility (eg size)

Answer 39

When a population becomes isolated and is exposed to selective pressures and evolves

Answer 40

Homologous structures (different function, same structure)

Answer 41

When unrelated species occupy the same environment and are subjected to similar selective pressures and show similar adaptations

Answer 42

Analogous structures (same function, different structure)

Answer 43

When 2 related species make similar evolutionary adaptions due to living in similar environments after diverging from a common ancestor

Answer 44

The mutual evolutionary sets of adaptations of two interacting species

Answer 45

Emergence of numerous species from a single common ancestor introduced to an environment

Answer 46

A theory of evolution stating organisms descend from a common ancestor gradually over time in a branching fashion, and small changes accumulate to big ones. And that fossils should exists as evidence for every stage of evolution with no missing links. This theory is not accepted as fossil record does not support it

Answer 47

It is the favoured theory today. It proposes that new species appear suddenly after long periods of no change. Most likely, a new species arises in a different place and expands it's range, competing and replacing ancestral species that become extinct

Answer 48

Intense heat, lightning, UV in the atmosphere provided energy for chemical reactions to produce the first organic cell. And due to the lack of free corrosively reactive molecular oxygen the cells created and persisted

Answer 49

First cells on earth were anaerobic heterotrophic prokaryotes

Answer 50

They absorbed molecules from the surrounding primordial soup as nutrients

Answer 51

Eukaryotic cells with nuclei/chlorplasts/mitochondria/etc evolved from prokaryotic cells, as tiny bacteria took up residence in larger prokaryotic cells and performed important functions for the host cell

Answer 52

Period of time in which many animals (every major phylum) appeared

Answer 53

They moved from oceans to land, filling every available NICHE as competition for Limited resources increased in oceans and evolved the traits necessary to survive in a dry environment

Answer 54

- lungs - skin to keep them from drying out - limbs to move - mechanisms for internal fertilization - shells to protect and keep eggs from drying out

Answer 55

- roots that anchor them to soil and absorb water - supporting cells to enable them to compete for light - vascular tissue to carry water upward - waxy cuticle to prevent leaves from dehydration - seeds, a protective package for embryo and it's food

Answer 56

Habitat destruction Environmental change Interdependence (one extinction leads to another)

Answer 57

Volcanic eruptions covered large areas with thick lava and emitted CO2, and increased global temperature. Almost wiped out life on earth

Answer 58

A massive asteroid crashed and caused a huge cloud of debris to billow in the atmosphere, blocking sunlight for months. Caused land and marine extinctions including all dinosaurs except birds

Answer 59

1. It's not always slow (eg bacterial resistance) 2. It does not occur at the same rate in all organisms (slower in crabs then humans) 3. It doesn't always make organisms more complex (eg starfish is bilateral in embryo, adult is radial) 4. It occurs in populations, not individuals (eg giraffes) 5. It is directed by environmental changes (eg streamline to move in the ocean)