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ANTHR 1300: Human Evolution > Prelim 1 > Flashcards

Prelim 1 Flashcards

Evolution and Human Variation - lectures 1-9

1
Q

Evolution

A

Change in a gene’s relative frequency in a population over time

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2
Q

Species

A

A population of individuals that interbreed and produce fertile offspring

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3
Q

Microevolution

A

Small changes within a species over time

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4
Q

Macroevolution

A

Major changes in a species’ form or behavior which categorize it as a new species

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5
Q

Natural selection

A

A mechanism through which small changes in a population accumulate into huge ones; increased frequency of traits that help individuals survive and reproduce

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6
Q

How does natural selection work?

A
  1. Limited resources -> competition to survive and reproduce
  2. Individuals in populations vary
  3. Inheritable traits that give an advantage will increase in relative frequency
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7
Q

Allopatric Speciation Model

A

Populations speciate after growing geographically isolated and being affected differently by natural selection

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8
Q

Character displacement

A

Populations sharing a geographic area adapt to different niches so they no longer compete

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9
Q

Types of reproductive barrier between species

A

Post-mating (offspring infertile or unhealthy) & pre-mating (form, lifestyle, mating activity too different to interbreed)

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10
Q

Biological Species Model

A

Species = population of individuals that interbreed and produce fertile offspring

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11
Q

Ring Species

A

Groups of neighboring pops. in which adjacent species can interbreed, but those at either “end” can’t

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12
Q

Hybrids

A

2 populations look and act totally different but can bear fertile offspring with unique “hybrid” traits

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13
Q

Evolutionary Species Concept

A

Use morphology to determine who is descended from whom

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14
Q

Phylogenetic Model

A

Examine groups to find a shared evolutionary history

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15
Q

What are the challenges to the Biological Species Model?

A
  1. Ring species
  2. Hybrids
  3. Paleobiology
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16
Q

How does speciation happen?

A
  1. A group within a population separates from the rest, usually geographically
  2. Natural selection decreases the prevalence of some traits and increases others
  3. Species can no longer interbreed with the original/divergent pops.
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17
Q

Nucleic Acids

A

Chains of nucleotide bases - DNA, RNA

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18
Q

Proteins

A

Chains of amino acids which perform varied functions

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19
Q

Which organisms have DNA?

A
  1. Viruses
  2. Prokaryotes
  3. Eukaryotes
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20
Q

DNA

A

Double-stranded macromolecule made of nucleotides which carries genetic information

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21
Q

Nucleotides

A

Organic molecules made up of a nucleotide base (A, T, C, G) and sugar

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22
Q

Gene

A

Section of DNA with instructions to make a protein

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23
Q

Chromosome

A

Large package of DNA stored in cell nuclei

24
Q

Locus

A

Location of a gene on a chromosome which remains constant for whole species

25
Q

Karyotype

A

Map of all your chromosomes

26
Q

How is DNA turned into a protein?

A
  1. Transcription: one DNA strand is copied onto messenger RNA (mRNA)
  2. Translation: RNA is turned into amino acids (three nucleotides make up one AA)
  3. End result: chain of amino acids form a protein
27
Q

What are the sources of variation in sexual reproduction?

A
  1. Crossing-over: every round of meiosis, a little bit of each chromosome may switch over
  2. Independent assortment: different pairs of alleles separate independently from each other
28
Q

Alleles

A

Different versions of a gene that may vary at loci

29
Q

Homozygous

A

Identical alleles for a trait

30
Q

Heterozygous

A

Different alleles for a trait

31
Q

Dominant allele

A

Will always create its protein

32
Q

Recessive allele

A

Will be blocked from creating its protein by dominant allele (only produces if homozygous)

33
Q

Codominant alleles

A

Two alleles that always produce their protein

34
Q

Phenotype

A

Observable traits, e.g. eye color or blood type

35
Q

Why isn’t all variation eliminated through generations?

A

Explanation: Traits are particulate - may “disappear” but reoccur in future generations, & combine but do not blend or change through genetics

Proof: plant experiments

36
Q

Gene pool

A

Abstraction of all genes present in a population

37
Q

Population

A

Group defined for a situation (usually a breeding population)

38
Q

4 causes of evolution

A
  1. Mutation
  2. Migration/gene flow
  3. Genetic drift
  4. Natural selection
39
Q

Mutation

A

Change in a gene’s actual chemical structure

40
Q

Types of mutation

A
  1. Chromosomal aberrations -changes in structure/number of chromosomes which are very destructive and affect many genes
  2. Point mutations - changes in a single nucleotide in a DNA change
    * May result in FRAME SHIFT - changes all proteins
41
Q

Gene flow (migration)

A

Movement of individuals

42
Q

Genetic drift (def & causes)

A

Chance changes in gene frequency, esp. in smaller populations, due to:
1. Random removal of alleles in meiosis
2. Founder Effect - small subset forms new group with higher frequency of certain genes
3. Inbreeding - reduces randomness, increases chance of rare recessive diseases

43
Q

Fitness

A

Reproductive success - how many genes an organism passes on, or how many (grand)offspring it has relative to others

44
Q

Subspecies

A

A genetically distinct population of a species which may or may not be speciating

45
Q

What are the assumptions behind race-IQ claims?

A
  1. Human “races” = subspeciees
  2. Each human has general intelligence measurable by a #
  3. That number can be objectively measured with a test
46
Q

Discordant variation

A

Variation that doesn’t match up - e.g. features used to determine “race” don’t map onto each other consistently

47
Q

Heritability

A

Proportion of total phenotypic variation caused by genetic variation (WITHIN a group) vs environmental variation

48
Q

H = ?

A

H = VG / (VG + VE)

49
Q

Clines

A

Relatively regular change in a biological trait (aka allele frequency) over geography

50
Q

How can we know if a trait is or was adaptive?

A

If clinal variation in the trait correlates strongly with variation in an environmental stressor

51
Q

Why is dark skin advantageous near the equator?

A

Melanin protects against UV rays:
1. Decreased risk of skin cancer from high UV exposure
2. Overdose of vitamin D -> kidney failure

52
Q

Why is pale skin advantageous near the poles?

A

Less melanin means absorbing more UV rays
1. Vitamin D needed for healthy bones and childbirth

53
Q

Heterozygote Advantage

A

Individuals benefit from heterozygote alleles when multiple selective forces act

E.g.: malaria is less successful on sickle cells, but sickle cells are unhealthy -> benefit to having one healthy allele and one sickle allele

54
Q

Adaptation

A

Degree to which an individual can utilize its environment as a result of natural selection on its ancestors

55
Q

Acclimatization

A

How an individual responds to environmental changes within its lifetime

56
Q

Developmental Acclimatization

A

Physiological changes from being born + growing up in certain extreme conditions

ANTHR 1300: Human Evolution (3 decks)

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