Microevolution Flashcards

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1
Q

Evolution-

A

genetic change in a

line of descent over the generations`

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2
Q

Microevolution-

A

how populations of organisms change from generation to generation and how new species originate

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3
Q

Macroevolution-

A

patterns of changes in groups of related
species over broad periods of time- determine phylogeny, or evolutionary relationships among groups of
species–how different species are related

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4
Q

Jean-Baptiste Lamarck–theories

A

Use and disuse, Inheritance of acquired characteristics, Natural transformation of species

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5
Q

Natural transformation of species-

A

because of the two above,
each generation of a species is transformed into a slightly different
more complex form
Ex- giraffe developed long neck from
stretched over time bc of necessity and this trait was passed to offspring

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6
Q

Inheritance of acquired characteristics

A

features that are

acquired during the lifetime of an organism can be passed on to offspring

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7
Q

Use and disuse

A

body parts of organisms develop more when used more, and unused parts weaken

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8
Q

Charles Darwin–explanation

A

Because of strong check on populations because of limited food
supply, inherited variations that are favorable to survival will be preserved, others eliminated. (Adaptations.) Natural Selection.

Ex- Galapagos finches- 13 different species all descended from
one single species, but because of the different environment on each island, different
traits selected for, different species evolved

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9
Q

Adaptations

A

evolutionary modification that improves chances of survival in specific environment

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10
Q

Natural Selection definition

A

better adapted organisms are more likely to survive, therefore population changes over time

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11
Q

Charles Darwin–aspects

A

Variation, Overproduction, Limits on population growth, Differential reproductive success,

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12
Q

Variation

A

individuals of a population exhibit variations,

some of which improve chances of survival and others which do not

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13
Q

Overproduction

A

every generation of a species has the

capacity to produce more offspring than can survive

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14
Q

Limits on population growth

A

struggle for existence

between individuals of a species because of limited resources

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15
Q

Differential reproductive success-

A

individuals that are
best adapted to the environment (contain most favorable
traits) are more likely to survive and reproduce,
therefore their traits will pass on and others will die off

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16
Q

Modern synthesis-

A

combines Darwin’s theory and Mendel’s theory to explain how these traits are passed on
Explains that variation is caused by mutations

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17
Q

Paleontology

A

studies fossils-remains or traces left in sedimentary rock by previously existing organisms.
Oldest layer at the bottom, upper layers are successively younger- allows scientists to place events recorded in rocks in their correct sequence.
Evidence of human life begins 100k years ago

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18
Q

halflife

A
halflife--amount of
time it takes half
of substance to
decay
after 2 halflives,
25% will be left.
after 3, 12.5,
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19
Q

Comparative anatomy-

A

in comparing structures from one organism to the next, scientists can discover how closely related they are

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20
Q

Homologous features/ homology- (+ex)

A

features that are derived from the same structure in a common ancestor

Ex- human arm, cat forelimb, whale front flipper, and a
bat wing all have a similar arrangement of bones, muscles, and nerves,
even though they are all used for different types of locomotion

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21
Q

Homoplastic features (analagous)/ homoplasy-

A

structurally
similar features that are not homologous but have similar functions that evolved independently in distantly related organisms
can lead to convergent evolution

Ex- wings of insects and birds evolved in order to function in flight, but each evolved from different ancestors.

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22
Q

Convergent evolution + ex

A

independent evolution of similar structures in distantly related organisms
Ex- aardvarks, anteaters, and pangolins all resemble one
another in lifestyle and structural features. All have strong, sharp claws, elongated snouts, long, sticky tongues, but each evolved from a different order

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23
Q

Vestigial structures- + ex

A

organs that are nonfunctional or
undersized. These are remnants of more developed structures that were functional in ancestral organisms
Ex- in humans, the coccyx (fused tailbones), wisdom teeth, muscles that move our ears. (Usually not eliminated entirely)

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24
Q

Biogeography-

A

study of past and present geographic distribution of
organisms, which affects their evolution. Unrelated species can
therefore look alike when found in similar environments
can occupy different niches but if they live in the same habitat

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25
Q

placental v marsupial

A

humans–placental–placenta forms, organ of exchange between
mother and baby, meaning all development happens in utero in amniotic sac
marsupial–give birth to immature baby which crawls out and up into the pouch, filled with tissue

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26
Q

Embryology + ex

A

“Ontogeny recapitulates phylogeny”- there are similar
stages in development among related species (ontogeny). This helps
establish evolutionary relationships
recapitulates–teaches
phylogeny–relationships
gill slits and tails are found in fish, chicken, pig, human embryos

27
Q

Molecular biology-

A

studies nucleotides and amino acid sequences of
DNA and proteins from different species. Closely related species
share higher % of sequences than species distantly related
more than 98% of nucleotide sequence in
humans and chimpanzees are identical

28
Q

Stabilizing selection:

ex

A

individuals with extreme or unusual traits are eliminated
while individuals with the most common traits are best adapted

Ex- larvae of certain fly bore into a plant and are enclosed in a
tumor until they metamorphose into adults. Large tumors, or
galls, are easily preyed on by woodpeckers, while small galls
are preyed on by wasps. Therefore, flies that form intermediate galls
are best selected for

29
Q

Directional selection:

ex

A

Favors traits that are at one extreme while traits at the opposite extreme are selected against
Ex- insecticide resistance- the few insects that contain
resistance to an insecticide will survive and produce offspring
after several generations, population will consist of nearly all insectide-resistant

Ex- peppered moth/ industrial melanism- before the industrial
revolution, light-colored moths best camouflaged with the
lichens covering the trees, while the dark colored moth was
rarely found since it was easily preyed upon. After the
industrial revolution, the lichens were killed, exposing the dark
bark below. Therefore, the dark colored moths was now better
camouflaged and it increased in frequency

30
Q

Disruptive selection: + ex

A

Environment favors extreme or unusual traits while selecting against intermediate traits
Ex- weeds exist in very tall forms in the wild because they can
better obtain sunlight. However, in lawns, only short weeds exist bc these
escape mowing
middle ones=no selective
advantage

31
Q

Sexual selection:

A

Traits that allow males to mate with a large amount of females
and maximize the quantity of offspring produced have a selective advantage and are passed on to offspring (male competiton)
Females put a greater investment of energy into producing
offspring, so they choose superior males
leads to sexual dimorphism

32
Q

Male competition

A

allows for mating opportunities to the strongest males, leading to the evolution of antlers and horns

33
Q

Female choice

A

females choose traits or behaviors that

are attractive, like colorful feathers or elaborate mating behavior

34
Q

sexual dimorphism-

A

differences in appearances of males and females within a species

35
Q

Artificial selection + ex

A

Directional selection carried out by humans when breeding plants or animals that possess desirable traits
Ex- certain breeds of dogs; brussel sprouts, cauliflower,
and broccoli all come from one species of wild mustard

36
Q

Gene flow

A

introduction or removal of alleles from a population when emigration or immigration occur

37
Q

Genetic drift

A

random change in allele frequencies over generations brought about
by chance. When populations are small, genetic drift has a greater effect and can influence evolution. 2 types.

38
Q

Types of genetic drift

A

bottleneck + founder effect

39
Q

bottleneck

A

when very few individuals rebuild a population after a severe reduction in population size

40
Q

Founder effect + ex

A

type of bottleneck in which a few individuals leave a population and establish a new one somewhere else

Ex–one of the founders of the Amish possessed allele for polydactyly and this trait now occurs at a large scale

41
Q

nonrandom mating

A

individuals choose mates based on their particular traits which could be similar or different from their own

42
Q

sexual selection

A

females choose males based on attractive appearances or abilities

43
Q

inbreeding

A

nonrandom mating among closely related relatives, which have many alleles in common. lowers fitness (ability to form surviving offspring) of population

44
Q

Mutations–>Variations

A

can invent new alleles that never previously existed

45
Q

Sexual reproduction

A

allows for genetic recombination: Crossing over during prophase I, Independent assortment during metaphase I, Random joining of alleles during fertilization

46
Q

Diploidy

A

more variation is maintained in a population because of the presence of two copies of every gene
the recessive allele can be hidden but passed on

47
Q

Outbreeding

A

mating with unrelated partners creates new allele combinations

48
Q

Balanced polymorphism

A

maintenance of different phenotypes in a population

49
Q

Heterozygote advantage

A

Individuals that are heterozygous have a greater selective advantage than either homozygous condition. Therefore-both alleles and all 3 phenotypes maintained in population

50
Q

sickle cell anemia

Heterozygote advantage

A

Ex- sickle cell anemia- those that are homozygous for sickle cell (Hb S Hb S ) die before puberty. Those that have Hb A Hb A are normal. Those that are heterozygous- Hb A Hb S are generally healthy but have reduced oxygen- carrying capabilities during exercise. However- in Africa 14% of population are heterozygous bc of a selective advantage making them resistant to malaria

51
Q

Frequency dependent selection (minority advantage)- + ex

A

when least common phenotypes have a selective advantage. However, they soon increase in frequency and lose their selective advantage
phenotypes therefore alternate between the two

Ex- predators form a “common representation” of their prey in order to optimize its search. Prey that rare escapes until it’s no longer rare

52
Q

Neutral variation-

A

variation that does not have a selective advantage or disadvantage

53
Q

Genetic equilibrium

A

when frequency of alleles in a population remains constant from generation to generation

54
Q

In order for equilibrium to occur, the following conditions must be true

A

random mating and no genetic drift, gene flow, mutations or natural selection

55
Q

P

A

frequency of dominant allele

56
Q

Q

A

frequency of recessive allele

57
Q

p2

A

frequency of homozygous dominant individuals

58
Q

q2

A

frequency of homozygous recessive individuals

59
Q

pq + qp = 2pq

A

frequency of heterozygous individuals

60
Q

hardy-weinberg equations

A

p + q = 1 (sum of all alleles = 100%)

p 2 + 2pq + q 2 = 1 (sum of all individuals = 100%)

61
Q

if the population is at equilibrium, what will happen to frequencies?

A

frequencies will be the same in every generation

62
Q

In most natural populations, are the conditions observed?

A

not obeyed

63
Q

What does it mean when the genotypes and phenotypes are in different proportions?

A

one of the conditions isn’t being met