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Evolution - BIOL*2400 > Midterm 1 - Review > Flashcards

Midterm 1 - Review Flashcards

1
Q

Synapomorphy

A

A shared derived character that is shared by a lineage and its immediate ancestor

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2
Q

Is Evolution Just a Theory? Why or Why Not?

A
  1. Scientific theories are backed by multiple lines of evidence
  2. Evolution is similar to other scientific theories
  3. Evolution theory overwhelmingly accepted by biologists
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3
Q

How do we know whales are mammals?

A

Whales share synapomorphies with mammals
- mammary glands
three middle ear bones
- hair in developing embryos

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4
Q

Why is it a misconception that evolutionary biologists are searching for missing links?

A
  1. Biologists expect the fossil record to be incomplete - right type of sediment is needed
  2. Available molecular, morphological, embryological evidence strongly supports relationships between current and past species
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5
Q

How can teeth be used to establish whether an animal is freshwater or marine

A
  • O18/O16 ratio higher in saltwater
  • Higher ratio in teeth of marine animals
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6
Q

Vestigial Organs

A

Organs, tissues or cells in a body which are no more functional the way they were in their ancestral form of the trait

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7
Q

Why is it a misconception that organisms are perfectly adapted by their environment?

A
  1. Natural selection works with available genetic variation
  2. Dolphin embryo still makes hindlimb buds that disappear later in development
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8
Q

Why is it a misconception that evolution occurs for the good of the species?

A
  1. natural selection for traits that are beneficial for individuals or their genes in a particular environment
  2. Traits bod for individuals can still be selected for the good of the species
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9
Q

Pseudo Genes

A

Genes that are still present but not functional

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10
Q

Why is it a misconception that evolution results from individuals continually adapting to their environment? (4)

A
  1. Evolution works on inherited traits
  2. Acquired changes are not passed to offspring
  3. Populations evolved individuals do not evolution results from changes in allele frequency
  4. Long lived organisms living in small populations cannot usually adapt to rapid evolutionary changes in their environment so often go exist
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11
Q

Can genetic drift cause maladaptation of small populations?

A

Yes

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12
Q

What is the scientific method in evolutionary biology

A
  1. Observations
  2. Generate hypothesis
  3. Test predictions
  4. Revise your hypothesis
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13
Q

Lamarckian Evolution

A
  • also called the first law stated that all such changes were heritable continuous, gradual change of all organisms, as they became adapted to their environments
  • Viewed species as populations of individuals showing variation
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14
Q

Charles Lyell

A

Popularized idea that earth changes gradually

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15
Q

Ernest Haeckel

A
  • (poor biological illustrator)
  • Designed multiple phylogenetic trees reflecting evolutionary pathways.
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16
Q

Jean-Baptiste Lamarck

A
  • Discarded concept of fixed species
  • Viewed species as populations of individual
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17
Q

Thomas Malthus

A

Human population size limited by resource

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18
Q

Charles Darwin

A

Proposed natural selection as the mechanism that explained decent with modification

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19
Q

Alfred Russel Wallace

A

Sent Darwin a letter from tenant, indonesia in february that independently formulated the ideas of natural selection

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20
Q

Darwins theory of evolution by natural selection

A
  1. Individuals within species are variable
  2. Some of phenotypic variation among individuals is inherited by their off spring
  3. In every generation more offspring are produced that can survive therefore, only some will breed
  4. The survival and reproduction of individuals is not random: individuals with the most favorable variation will survive and reproduce the most -> naturally selected
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21
Q

Decent with modification (4)

A
  • The non-consistancy of species
  • the decent of all organisms from common ancestors
  • The gradualness of evolution
  • The multiplication of species
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22
Q

What was the difficulty with darwins theory

A
  • Darwin believed in blending inheritance
  • He never completely resolved the relationship between natural selection and the effect of use and disuse
  • He could not answer the criticism, that the initial effects of natural selection would be nullified by crossing between the selected individuals and the rest of the population with black fur
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23
Q

Mendel

A
  • Genes as particles
  • random segregation
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24
Q

Dobzhansky

A

Book synthesized empirical results by mendel and fruit fly geneticist and population genetics with darwins theory

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25
Q

Mayr

A

Geographical speciation

26
Q

Simpson

A

Fossil horse series showed gradual evolution

27
Q

Stebbins

A

Instant speciation by autoplyploidy

28
Q

Describe Evolution by natural selection

A
  1. Populations contain genetic variation that arise through random mutation and recombination
  2. Populations evolve by changes in gene frequencies brought by random drift, gene flow, and natural selection
  3. Most adaptive genetic varieties have individually slight phenotypic effects so that phenotypic changes are gradual
  4. Diversification comes about by speciation, which ordinarily entails the gradual evolution of reproductive isolation among geographically isolated populations
  5. Speciation processes eventually give rise to changes of such great magnitude as to warrant the designation of higher taxonomic levels
29
Q

Define Biological Evolution

A

Change in the heritable traits of a population that occurs between generations because of at least one of:
1. Natural Selection
2. Genetic drift
3. New mutation or recombination in a genomic DNA sequence
4. Immigrant from a genetically divergent population that successfully reproduces.

30
Q

Describe a cladogram:

A

Only the branching order matters.

31
Q

Synapomorphy

A

A shared derived character state. Specifically a trait that evolved in the immediate common ancestor of the group and was inherited by all of its immediate descendants

32
Q

Outgroup

A

Used to infer what is ancestral and what is derived.
- purpose is to identify ancestral character state

33
Q

Name 3 ways to identify a species

A
  1. Biological species concept
  2. Morphological species concept
  3. Phylogenetic species concept
34
Q

Biological Species Concept

A

groups of interbreeding populations that are reproductively isolated from other such groups

35
Q

Morphological species concept

A

Difference in the mean value of a diagnostic morphological trait between two groups is greater than the average variation within each group

36
Q

Phylogenetic species concept

A

smallest possible group descending from a common ancestor and recognizable by unique, derived (binary traits)

37
Q

Define Maximum Parsimony

A

Phylogeny has fewest changes in the state of a character

38
Q

Homoplasy

A

Character state similarity not due to common descent

39
Q

What can cause homoplasy?

A
  1. Convergent evolution - independant evolution of a similar trait
  2. Evolutionary reversals - reversion back to an ancestral character state
40
Q

Polytomy

A

relationship uncertain

41
Q

Are any animals alive today primitive?

A

no

42
Q

What did Shubin and Daeshler do?

A
  • predicted where transition fossils would be found
  • searched rocks from northern canada
43
Q

List the 4 reliable characters

A
  1. independent
  2. homologous
  3. maximum variability but minimize homoplasy
  4. Available in large numbers
44
Q

Substitution

A

A mutation that becomes fixed in a population or taxon

45
Q

Parsimony Informative State

A

A base position site that has at least two different bases that are each present in at least 2 different species.

46
Q

Parsimony Principle

A

The tree with the minimum number of hypothetical evolutionary changes is the preferred tree

47
Q

Maximum Likelihood Tree

A

Better than maximum parsimony (MP) if unequal rates of evolution in different branches.

48
Q

How do you build a phylogeny with genetic data?

A
  • each nucleotide a potentially informative character
  • homoplasty is common - four possible character states
  • genes differ in rates of evolution
  • slowly evolving genes useful for distantly related species
  • Rapid evolving genes useful for closely related lineages
  • shortest phylogeny estimated with computer: must find shortest trees globally rather than locally
49
Q

Mutations

A

any change to the genomic sequance in germline

50
Q

List the applications of DNA markers in ecology

A
  1. eDNA barcoding to ID species present
  2. Population genetic structure: management units of fisheries or wildlife populations
  3. figuring out who is the biological father
  4. estimating rates of migration amoung populations (Fst)
  5. Estimating genetic diversity in small or endangered populations
51
Q

What makes pseudogenes useful for building phylogenies?

A

They are non-functional

52
Q

what are 4 modern DNA samples that markers can analyze

A
  1. collect tissue
  2. use DNA kit to extract DNA
  3. PCR-amplify target DNA fragment
  4. Determine genotypes with PCR assay or targeted next generation sequancing
    4b. Run PCR priduct on capillary filled with acrylamide gel to determine its size
53
Q

What are the advantages of PCR assays

A
  1. Can genotype very small tissue samples, feathers, hair…
  2. Can use easy crude DNA extraction methods with colour coded kit
  3. Millions of copies of your target DNA fragment: so can determine sequance
54
Q

mtDNA markers

A
  • haploid circular genome like bacteria
  • maternally ingerited and haploid: 1/4 Ne population size relative to nuclear genome
  • mtDNA genome no recombination
  • population genetic structure
  • DNA barcoding to identify animal species and what they eat
55
Q

Gel Electrophoresis measures..

A

Genetic variationin populations

56
Q

Micro satellites or (simple tandem repeats markers

A
  • nuclear genome therefore diploid and biparently inherited
  • neutral marker unless near an exon
  • mutation rate very high once number of repeats is large - many allels per locus
  • cannot estimate allele frequancies for very small populations
  • cannot be reliably machine scored and expensive
57
Q

Hardy-Weinberg Theorem

A
  • Population allele frequencies do not change between generations if:
  • population is infinitely large
  • genotypes do not differ in fitness
  • there is no mutation
  • mating is random
  • there is no migration
58
Q

What does genetic drift do to gene frequencies

A
  • causes them to change in populations
  • Genetic drift is inversly related to population size
59
Q

T or F: alleles are lost more rapidly in very small populations

A

True

60
Q

T or F: Evolution caused soley by genetic drift is more likely in small populations?

A

True

61
Q

Genetic Drift

A

The random change in genetic composition of population arising as a consequance of sampling gametes from a finite population

62
Q
A

Evolution - BIOL*2400 (2 decks)

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