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Gen Bio II (yr1sem2) > Chapter 20 ch 1 > Flashcards

Chapter 20 ch 1 Flashcards

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1
Q

evolutionary theory

A

was created by Charles darwin

used by humans to vaccines

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2
Q

Charles Darwin year: 1831

A

5 year voyage on the H.M.S. Beagle around the world to study oceans and collect biological info

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3
Q

Natural Selection

A

slight variations among individuals affect chances for survival and production of offspring

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4
Q

theory of evolutionary change (def)

A
  1. Species change over time. Groups of organisms change (what they eat, where they live, the numbers of them with a certain trait etc)
  2. Species all share common traits, but the size and things may change.
  3. Process of this change is natural selection
    * populations evolve
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5
Q

if they are evolutionarily successful,

A

can they reproduce? Are they surviving?

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6
Q

Population

A

a group of individuals of the same species that live and interbreed in a particular geographic area at the same time

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7
Q

Adaptation meaning

A

The process by which characteristics that are useful evolve
The characteristics themselves – something that has helped an organism adjust to conditions in an environment
*organism has adapted when scientists can demonstrate that some organisms survived the event better than others

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8
Q

Charles Darwin year 1866

A

Mendel publishes his paper of pea genetics (dominant and recessive traits)

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9
Q

Charles Darwin year 1900-1918

A

Basic principles of inheritance genetics established

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10
Q

Charles Darwin year 1947-1960

A

Emphasis on chromosomal evolution, models of speciation, geographic variation, population genetics

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11
Q

Charles Darwin year 1970(?)

A

Intro of molecular variation, phylogenetic analysis, sexual selection, behavior

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12
Q

Charles Darwin year 1980-present

A

Exponential increase in studies of molecular evolution and developmental processes of evolution

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13
Q

Sexual selection

A

introduced by Darwin, is that there are specific traits that organisms use to choose traits like Nice feathers, etc.

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14
Q

Heritable genetic variation:

A

potential for change because there is some variation from your parents that you received
ie. phenotype

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15
Q

phenotype

A

the physical expression of an organisms genes (characteristics like eye color, hair color)

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16
Q

trait

A

Specific forms of a characteristic (brown eyes)

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17
Q

Heritable trait

A

form of a characteristic at least partly determined by genes

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18
Q

genotype

A

genetic makeup of an organism. This is like Aa,

There must be differences in the genotypes as certain genotypes are more present than others therefore adaptations

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19
Q

population genetics’ three main goals

A

Explain origin and maintenance of a genetic variation
Explain the patterns and organization of genetic variation
Understand the mechanisms that cause changes in allele frequencies in populations

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20
Q

alleles

A

different forms of a specific gene

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21
Q

Gene pool

A

sum of all copies of all alleles at all loci in a population

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22
Q

two tenants of evolution

A

Survival and reproduction

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23
Q

Allele frequency

A

the proportion of a given allele or genotype in a gene pool at a particular locus

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24
Q

p and q

Study These Flashcards
A

allelic frequencies

25
(P +Q)^2
phenotypic frequencies
26
P^2, 2pq, q^2
genotypic frequencies
27
5 restrictions on hardy equilibrium
- No mutations must occur so that new alleles do not enter the population. - No gene flow can occur (i.e. no immigration/emigration of individuals into, or out of, the population). - Random mating must occur (i.e. individuals must pair by chance) - The population must be large so that no genetic drift (random chance) can cause the allele frequencies to change. - No natural selection can occur so that certain alleles are not selected for, or against.
28
p can be calculated by
number of copies of the allele in the population OVER sum of all alleles in the population
29
polymorphic
multiple alleles
30
monomorphic
has one allele and frequency is one
31
calculating allelic frequencies (Conant)
add up all the allele ASK PEOPLE
32
When the value isn’t 1 in hardy weinberg
Important for predicting the approximate genotype frequencies of a population Can show which mechanisms of evolution are acting on a population by how it is deviating from H-W equilibrium
33
Consequences of ideal conditions of hardy Weinberg:
Frequencies of alleles at a locus remain constant from generation to generation Following one generation of random mating the genotype frequencies occur in the following proportions:
34
mutations (The Mechanisms of Evolution)
Any change in an organism’s DNA Appear to be random Harmful or neutral changes may become advantageous over time Can restore alleles to populations that have been lost Mutation rates low for most loci (one in a million)
35
Gene flow (The Mechanisms of Evolution)
Migration of individuals of similar species from other populations Relatively common May add new alleles to gene pool May change frequency of alleles
36
Genetic drift (The Mechanisms of Evolution)
Random changes in allele frequencies | Harmful alleles may increase, advantageous alleles may be lost
37
Population bottlenecks (The Mechanisms of Evolution)
large populations go through large loss of numbers, genetic variation may be lost usually followed by founder effect: new individuals populate a new region bringing new alleles, change in genetic variation, often found after bottleneck
38
Non-random mating (The Mechanisms of Evolution)
Choosing particular genotypes as mates, homozygous genotypes overrepresented includes self-fertilization
39
fitness (Mechanisms of Evolutionary Change)
the reproductive contribution of a phenotype to subsequent generations relative to the contributions of other phenotypes Determined by the average rates of survival and reproduction of individuals with a certain phenotype
40
natural selection results are
variable – most advantageous characteristics are influenced by multiple alleles and genetic variations
41
Stabilizing selection (Mechanisms of Evolutionary Change)
favors average characteristics/individuals (human height, birth weights) Reduces variations in populations without changing mean values - most common
42
Directional selection (Mechanisms of Evolutionary Change)
favors individuals that vary in one direction from the mean of population If apparent in multiple generations an evolutionary trend is seen (toxin resistance in snakes, Texas Longhorns)
43
Disruptive selection (Mechanisms of Evolutionary Change)
– favors individuals that vary in opposite directions from mean of population Bimodal distribution of a phenotype (black -bellied seedcracker)
44
Sexual selection (Mechanisms of Evolutionary Change)
acts on characteristics that determine reproductive success Darwins’s explanation for the evolution of apparently useless characteristics (bright colors, long tail, horns, antlers, elaborate courtship displays) These features either improved the ability to compete for access to mates or made bearers more attractive to mates characteristics may indicate increased, health, reproductive fitness
45
Neutral alleles (How is Genetic Variation Maintained?)
an allele that is no better or worse than alternative alleles at the same locus Tend to accumulate in a population over time providing genetic variation
46
Sexual recombination (How is Genetic Variation Maintained?)
generates an endless variety of genotypic combinations increases the evolutionary potential of a population Gives more variability (good evolutionarily)
47
Frequency-dependent selection (How is Genetic Variation Maintained?)
the maintenance of a polymorphism when the fitness of a genotype depends on its frequency in a population (scale eating fish) - more polymorphism usually means that more organisms are going to survive - Having different organisms have different characteristics (ie breeding in June vs october) helps keep population alive - Having different coloured body parts stops predation etc. - Multiple genotypes in the population help maintain the species as a whole
48
Environmental variation (How is Genetic Variation Maintained?)
no single genotype performs well in all environmental conditions Favors genetic variation
49
Geographically distinct subpopulations (How is Genetic Variation Maintained?)
subject to different selective pressures in different environments and areas
50
Developmental processes (Constraints on Evolution)
we build on what we already have. If there are new structures and reproductive ways, it was built on the basis of what was already there Means that evolution takes a long time may sacrifice one ability to gain another
51
Trade-offs (Constraints on Evolution)
fitness benefits must outweigh fitness costs | Maintaining features may be energetically costly, lifespan may be shorter
52
Short-term and long-term outcomes may differ (Constraints on Evolution)
it is not always known how a short-term noticeable evolutionary feature will fare in the future How evolutionary processes act may change over time different lineages may evolve in different directions
53
how have humans influenced evolution?
Reduced loss of life due to predators, bad weather Increased loss of life due to disease, accidents, war, murder Control of species we consider “pests”
54
name some mechanisms of evolutionary change
gene flow etc.
55
what result in adaptation?
any selections
56
how is genetic variation maintained in populations?
types of variations
57
contraints on evolution?
long term, fitness, structure etc.
58
Natural selection vs adaptation
natural selection is what a pressure selects for Population has adapted when it survives the pressure Adaptation is a response to selective pressure
59
most likely to result in adaptation?
directional selection

Gen Bio II (yr1sem2) (18 decks)

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