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Human evolution > Exam 1: Week 3 > Flashcards

Exam 1: Week 3 Flashcards

1
Q

problems with Darwins theories (2)

A
  1. blended inheritance
  2. inheritance of acquired traits
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2
Q

blended inheritance

A

traits are not directly inherited from one of the parents and instead it was blended between the parents ⇒ mixings of their contributions

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3
Q

inheritance of acquired traits

A

traits acquired during the lifetime leading to the adaptation of a species over time ⇒ Lamarck came up with this
- Similar to things like epigenetics and DNA methylation

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4
Q

Pangenesis

A

Darwin’s theory of heredity
- ALL body cells produce gemmules that gather in reproductive organs (testes and ovaries) and this is what contributes from the parents to the offspring

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5
Q

what does pangenesis account for? (4)

A
  • atavisms
  • blended inheritance
  • Lamarckian inheritance
  • limb regeneration
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6
Q

atavisms

A

ancestral traits that don’t normally express in individuals ⇒ primitive traits seen in early development stages but not necessarily seen later on

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7
Q

Lamarckian inheritance

A

traits that are modified during the parents life and passed to offspring

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8
Q

who was Gregor Mendel?

A

Austrian monk who experimented/crossed peas and looked at offspring
- figured out the process that inheritance material is passed down generations
- Publication describing his results was largely ignored until 1900 when rediscovered

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9
Q

artificial selection

A

when humans choose particular traits in breeding ⇒ over generations this becomes domestication

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10
Q

phenotype

A

expression of genetic material both physiologically (tissue, hormones, etc.) and behaviorally (reactions)
- Genes affect how much hormones are produced, how they are taken up, and how they influence behavior ⇒ there is some behavioral inheritance patterns

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11
Q

what was published in 1871?

A

Darwins descent of man
- Mendel published in 1865 and that was 6 years that Darwin could have read Mendel’s work and did not know he already figured out how inheritance happens
- Could have strengthened his argument of natural selection

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12
Q

gene

A

basic unit of inheritance ⇒ a segment of DNA or RNa that is transmitted from one generation to the next

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13
Q

allele

A

variation of a gene ⇒ different versions

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14
Q

diploid

A

an organisms has 2 versions of a gene inherited from a maternal and a paternal

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15
Q

what factors make up modern synthesis? (3)

A
  • evolutionary theory
  • population genetics
  • paleontology (fossils)
  • also other systems of biology like physiology, systematics, developmental bio, etc.
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16
Q

evolutionary theory

A

evolution via genetic inheritance ⇒ at a population level often

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17
Q

population genetics

A

how populations evolve over time

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18
Q

who wrote genetical theory of natural selection (1930)?

A

R.A fisher

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19
Q

who wrote the cause of evolution (1930)?

A

J.B.S Haldane

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20
Q

who wrote evolution: the modern synthesis (1942)

A

Julain Huxley

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21
Q

who wrote systematics and the origin of species (1942)?

A

Ernst Mayr

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22
Q

who wrote Tempo and mode in evolution (1944)

A

George Gaylord Simpson

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23
Q

Darwins definition of evolution

A

species change over long periods of time through small, gradual changes

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24
Q

Modern synthesis

A

change in the frequency of alleles in a population across generations

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25
what is evolution not? (4)
- Linear - Progressive - Pre-determined - A sequence with humans on top
26
what are the layers to DNA? (4)
1. 1st order: natural twisting 2. 2nd order: histone proteins the DNA helix is wrapping around - Methylation will influence the tightness of their wrapping to expose them to other elements which affect the DNA 3. 3rd order: nucleosomes which wind up tightly 4. 4th order: chromosome
27
how do genes work?
they store information in DNA - 4 base pairs ⇒ ATCG - Sometimes a few hundred base pairs and sometimes thousands - Genes change with recombination during division processes
28
what is the central dogma?
DNA transcribed to RNA translated to protein
29
who is mitochondrial DNA inherited from?
the maternal parent - Mitochondria produces ATP which is the energy used to fuel all cellular processes - Its DNA is responsible for its function
30
polygenic
traits controlled by multiple genes
31
monogenic
one gene controls a trait
32
pleiotropy
refers to the gene which affects many different traits
33
alleles
variations of a gene due to differences in DNA and may produce different phenotypes
34
genotype
genetic makeup - AA: two copies of allele A (homozygous) - Aa: one copy of allele A and one of a (heterozygous) - aa: two copies of allele a (homozygous)
35
phenotype
observable traits ⇒ phainein, to show + types, type - If A is dominant and a is recessive, genotypes AA and Aa have the same phenotype
36
genetic load
we all carry many recessive alleles and on average, we all carry at least a few alleles that would be lethal if we had two copies
37
how is latin part of scientific language?
Due to the Roman empire’s military conquest
38
what do phenotypes result from? (2)
1. Interactions among many different genes ⇒ height, weight, predisposition, etc. 2. Interactions with the environment
39
Phenylketonuria (PKU)
rare inherited genetic disorder (1/12,000 infants) where mutations in the phenylalanine hydroxylase (PAH) gene reduce ability to break down phenylalanine a essential amino acid - Autosomal recessive inheritance ⇒ not on a sex chromosome - Buildup of phenylalanine results in symptoms including in irreversible brain damage ⇒ phenylalanine hydroxylase enzyme does not work - Diet low in phenylalanine prevents symptoms ⇒ something other than breast milk
40
population genetics (evolution)
changes in frequency of alleles in a population across generations
41
hardy Weinberg equilibrium
frequency of alleles in a population will stay the same over time and evolution will not happen if certain conditions are met
42
mechanisms of evolution (4)
1. genetic drift 2. gene flow/migration 3. mutation 4. selection => natural, sexual, artificial
43
genetic drift
the frequency of genes changes due to chance - Bottleneck events
44
gene flow/migration
the movement of genes from one population to another - Genes could flow without movement by having offspring that go other places ⇒ sex
45
mutations
any change in the genome - errors in copying DNA, damage from radiation (UV or other), rearrangements of chromosomes, etc.
46
which evolutionary processes are random mechanisms? (3)
random changes in gene frequencies and don't produce adaptations - Mutation - Migration - Genetic drift
47
which evolutionary mechanisms are non random?
- Natural selection: something that occurs in nature to reduce certain alleles - Sexual selection: selection that involves mating success ⇒ leads to traits that inhibit survival - Artificial selection: selection done by humans to other organisms
48
selection
is non random and produces adaptations - traits evolve to live with us unintentionally
49
what are necessary and sufficient conditions for natural selection? (3NS4NS)
1. phenotypic variation of a trait in a population 2. heritability of the variation in that trait 3. differential reproductive success based on that variation
50
phenotypic variation benefits
If every phenotype is identical there will not be opportunity for selection - Also if the variation is just genetic ⇒ often genetic variation is silent and doesn’t affect phenotype
51
heritability of phenotypic variations
Needs to be some expression in the phenotype of the variation of the trait and it needs to be heritable
52
differential reproductive success
Not everyone has the same amount of offspring ⇒ often measured based on the offspring that survive to reproductive age
53
adaptations
a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection ⇒ kind of circular - Usually it does something helpful for an organism - Other mechanisms of evolution life drift, migration, mutation do not produce adaptations
54
costs of sex (4)
1. Producing males ⇒ hard to explain - By themselves they cannot produce babies - You don't need as many of them as “females” produce the babies 2. Each offspring only ½ related to parent - Organisms are for replicating genes - Presents sex as a huge problem because ½ relation 3. searching for mates ⇒ takes time and energy 4. Costs of sexual selection (ornamentation, weaponry, displays, fighting)
55
when does sex show up in evolutionary history?
about October or November - Most reproduction was asexual for 80 million years
56
what is interesting about aphids
they don't have sex in the spring - Eggs laid in late fall, winter in egg form, hatch in spring as females, produce parthenogenetically ⇒ produce females only until late summer when females produce both genders who mate and produce eggs through winter
57
what is interesting about desert grassland whiptails?
parthenogenetically reproduce (only females by courting each other and go through motion of mating) - Courtship is for show and doesn’t involve transmission of genes
58
what is interesting about Komodo dragons
No sex when island hopping - Isolated female komodo dragons in zoos can lay eggs and produce baby lizards
59
what is interesting about rotifers?
we mostly thought they asexually reproduced but they have facultative sexual reproduction so they mostly asexually reproduce but don't have to
60
facultative sexual reproduction
can switch between sexual and asexual reproduction
61
why do humans reproduce sexually?
there isn’t an answer biologists agree on - withstanding variable environments is a common explanation but it is not sufficient - RQH is also popular but also not sufficient to overcome the cost of sex universally - repairing errors in DNA is a function of sex ⇒ recombination - mitonuclear theory
62
advantages of sex (6)
- Increases genetic diversity - Increases rates of evolution ⇒ as a result of 1 - Repairs DNA during recombination - Brings together beneficial mutations - Masks harmful mutations - Eliminates harmful mutations
63
chromosome
meaning colorful bodies (greek) ⇒ humans have 23 pairs - 1-22 is autosomal and 23 are sex chromosomes
64
karyotype
a complete gene set ⇒ from Greek karyon, kernel - Kernel as in the nucleus ⇒ where chromosomes reside - One each from mom and dad ⇒ we are diploid
65
end card
hehe

Human evolution (9 decks)

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