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BIO 108 (Hunt Made These :)) > Evolution, Taxonomy/phylogenetics, speciation, variation/allele frequencies > Flashcards

Evolution, Taxonomy/phylogenetics, speciation, variation/allele frequencies Flashcards

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Biology 101 flashcards
1
Q

What is Systematics?

A

The theory and practice of classifying organisms based on evolutionary history (Phylogeny)

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2
Q

What are the 3 problems that rise with using common names when classifying animals & organisms?

A
  1. Different names for same species
  2. Same name for different species
  3. Common names may imply relationships that DO NOT exist
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3
Q

What are the 3 points Linnaeus proposed in his series Systema Naturae? What is this now called?

A

Linnaeus Proposed

  1. Use of latin as universal language of saentic (scientic?) nomenclature
  2. Use of unique binomen as name of each species
  3. Classify and group species using hierarchical categories based on relatedness and similarity -> Binomial system of nomenclature
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4
Q

What are the two parts of a binomial and what is the proper way of writing?

A

Binomial name has 2 parts

  1. Genus name and
  2. Specific name
  • Genus name and specific are always italicized
  • Genus is capitalized

EXAMPLE

Homo (Caps/Genus) Sapiens (Italicized/Species)

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5
Q

What is an ingroup?

A

An ingroup is the group whose relationships are in the main interest of untangling

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6
Q

What is an out-group?

A

One or more species that are distantly related to have the ingroup but have diverged from it at an earlier time. (Has BASIC similar features)

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7
Q

What type of information do systematists collect?

A

Collect information on morphology, behaviour, DNA sequences, and biochemistry

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8
Q

What is character? and what is state?

A

Character is a type of structure, behaviour, DNA sequence… ETC

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9
Q

What does the principle of Parisomy state about phylogenies and evolutionary events?

A

It states to choose the phylogeny that requires the fewest of evolutionary events because its more probably an event is a change from ancestral state

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10
Q

What is a clade? How do we identify one?

A

A clade is a group of species that contain a common ancestor and ALL of its descendants and no other unrelated data

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11
Q

What is Synapomorphy? What are they useful for?

A

Synapomorphies are shared, derived states BETWEEN 2 groups (Only some members have it)

Useful for constructing phylogenetic relationships

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12
Q

What are Homologous character states?

A

Homo = Same

They look the same and have same evolutionary origin

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13
Q

What is a symplesiomorphy?

A

Symplesiomorphies are shared ancestral states (Everyone has them)

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14
Q

What are analogous character states?

A

Appear the same, but actually evolved independently

i.e Bat’s wing and Bird’s wing

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15
Q

What is convergent evolution?

A

Convergent evolution occurs when 2 species from different ancestors evolve similar traits because they are trying to adapt to a similar environment

i.e. Fins of Penguins VS. Fins of Seals

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16
Q

What is a Paraphyletic Group?

A

Groups that do not contain all descendants of a common ancestor

-Result of a removal of taxa

(Leaving a group out)

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17
Q

What were the few theory’s about extinction in the Pre-Darwin era?

A
  1. Natural Disasters
  2. One species changing slowly into another
  3. Supernatural Disasters
  4. Hiding somewhere
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18
Q

What is a polypheltic group?

A

When taxa get lumped together even though they do not share recent ancestor

i.e. grouped by superficial similarities

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19
Q

What did Cuvier hypothesize about extinction? (and species change)

A

Though species DONT change over time and that the succession of life form in earth’s strata overtime is bc of catastrophe that causes local extinction

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20
Q

What did Lamarck hypothesize about species change/extinction?

A

Inheritance of acquired characteristics.

-Traits can be passed down to offspring (Traits acquired over a single lifetimes)

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21
Q

What did Darwin notice when he got to the Galapagos? What did he conclude from his findings?

A

He noticed the VARIATION in the beak sizes of finches depending on their habitats.

He concluded that this variation is due to their use of habitat and way of feeding that arose from descent with modification

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22
Q

What are the 3 of the first observations Darwin made and what inference did he come up with based on that?

A

OBSERVATION 1
-Organisms produce many more offspring than survive

OBSERVATION 2
-Most pop are stable

OBSERVATION 3
-Resources are limited

INFERENCES
organisms must compete for these limited resources. Some dont succeed.

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23
Q

What other 2 observations did Darwin make and what 2 inferences arose from those?

A

OBSERVATION 4
-Variation exists among individuals within species.

INFERENCE 2
-Individuals w/ advantageous variations have more offspring

OBSERVATION 5
-Variation is heritable

INFERENCE 3
Heritable variations are likely to provide individuals with competitive advantage

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24
Q

What is Darwin’s theory of descent with modification?

A

An individual will have a certain variation (Most likely advantageous) therefore that individual mates and produces offspring that result in adaptive changes over generations.

25
Q

What did the process of natural selection give rise to?

A

Natural selection gives rise to adaptations and it is context-dependent

(No innate tendency towards perfection)

26
Q

What are the 4 types of variations?

A
  1. Form (Phenotypic)
  2. Function (Phenotypic)
  3. Behaviour (Phenotypic)
  4. Genetic make up (Genotypic)
27
Q

What 2 things need to be present for natural selection to act on variation?

A

They must be seen by the environment (Phenotypic expression) and be heritable (Caused by genotype)

28
Q

What are the 4 sources of variation?

A
  1. Mutation
  2. Recombination
  3. Independent Assortment
  4. Fertilization
29
Q

What is a selective agent? What is selection pressure? Examples?

A

Component of natural environment that consistently causes differential survival/reproduction

  • The intensity with which the selective agent acts on a population to evolve is selective pressure
    i. e. Biotic and abiotic
30
Q

What are 4 underlying points for natural selection?

A
  1. Heritable Variation
  2. Limited resources therefore more offspring
  3. Favourable traits survive and reproduce (Have more fittness)
  4. Adaptation (coding of fit individuals increase overtime)
31
Q

How can fossil record in layers of sedimentary rock (Strata) provide evidence for extinction?

A

You can find organisms that existed in the past by looking at layers of strata above the modern layer bc each layer corresponds to age.

32
Q

What are vestigial structures?

A

Vestigial structures are “left-over” structures from a possible organism in ancestral period; but current organisms does not posses it

33
Q

What is the selection pressure in the group of bacteria that result in resistant bacteria?

A

Anti-biotics (abiotic pressure)

34
Q

What is Taxonomy?

A

Practice of naming and classifying organisms

TAXO: Arrange

NMOS: Knowledge

35
Q

Evolution is the change in ________ in a population (gene pool) between generations

A

frequency

36
Q

What are 4 factors that can change allele frequency? What is the only mechanism in the four listed that can give rise to adaptation

A
  1. Natural Selection
  2. Mutation
  3. Gene Flow
  4. Genetic Drift
    - Natural Selection is the only mechanism that can give rise to adaptation
37
Q

What are mutations? What are properties of mutations?

A

Mutations are a change in an individuals DNA … can occur through replication errors or structural damage to DNA
- Mutations re random and can be good, bad, or neutral depending on the context it occurs in

38
Q

What is Gene flow? What effect does it have on variation? What effect does it have on allele frequency?

A

Gene flow is the transfer of genes (alleles) between 2 populations
examples include: interbreeding and migration
- it increases variation within a population and decreases variation between populations (they all start to look alike)
- increases allele frequency within a population

39
Q

What is genetic Drift? What are two types of genetic drift and what effect does it have on allele frequency?

A
  • changes in allele frequency due to chance
  • allele frequencies drift from one generation to the next and has greater impact on smaller populations
  • two types: bottleneck and founder effect
  • decreases allele frequency within a population
40
Q

What is founder effect?

A
  • small fraction of population migrates or separates from original
  • results in evolution because the new population has a different genetic make up as the original population and after many years will not be able to mate with the original population therefore becoming its own species.
41
Q

What is the bottle neck effect?

A
  • when a natural event or catastrophe occurs by chance and only a subset of the original population survive and reproduce
  • you end up with a new generation with different alleles and evolution occurs over time
  • rare alleles are most likely lost during the drift since they didn’t have much to begin with
42
Q

What are the 3 ways natural selection can affect the distribution of allele frequencies? Describe each.

A
  1. Directional Selection: when natural selection favours one side of the extreme and the variance stay the same but mean changes
  2. Disruptive selection: natural selection favours both ends of the extreme and not the middle. Variance stays the same and mean changes
  3. Stabilizing Selection: intermediate or common phenotype favoured. Natural selection favours against the extremes and mean stays the same while variance decreases
43
Q

What 8 ways to maintain variation?

A
  1. Mutation
  2. Recombination (crossing over … meiosis and mitosis)
  3. Independent assortment (of alleles)
  4. fertilization
  5. Disruptive selection (type of natural selection) where both ends are favoured therefore they are likely to mate with each other
  6. Gene flow (between populations)
  7. Negative frequency-dependent selection
  8. Heterozygote advantage
44
Q

What is frequency-dependent selection?

A

in negative frequency dependent selection, the rare (least occurring) genotype has an advantage over the the most occurring genotypes

45
Q

What is Heterozygote advantage?

A

when a genotype thats heterozygote has a higher rate of fitness i.e. sickle cell anemia heterozygous –> people live due to protection from both sick cell anemia and malaria

46
Q

What are the two modes of evolution? Describe each.

A
  1. Microevolution: evolution at the population level –> occurs mainly through selection. Incl. mutations, genetic drift, genetic flow..etc.
  2. Macroevolution = evolutionary change above the species level –> incl. origin of complex novel characters, appearance of higher taxa, mass extinctions and speciation (emergence of new species)
47
Q

Describe the Biological Species Concept

A

Consists of a group of potentially interbreeding individuals that are reproductively isolated from other such groups (they can’t mate with members of different species)

48
Q

What are 4 main problems with the biological species concept?

A
  1. only applies to sexually reproducing species (i.e. not bacteria)
  2. Suggests that two different species would never mate and produce offspring (but we can have successful hybridization that is man-made)
  3. Ecological species concept = species is a set of organisms adapted to a particular set of resources called a niche in the environment (species is based on its environment)
  4. Phylogenetic species concept – evolutionary history –> grouping organisms based on their phylogenetic tree clusters
49
Q

Describe Reproductive isolation via pre-zygotic isolation mechanisms. What are the 5 pre zygotic isolation mechanisms?

A
  1. Ecological (habitat selection) –> live in different parts of the environment and never get a chance to interact
  2. Temporal isolation –> kept separate by mating times during the year
  3. Behavioural isolation –> only mate with some pheromones
  4. Mechanical isolation –> the P does not match the V
  5. Gamete isolation —> sperm and egg won’t fuse to make an offspring
50
Q

What are 3 post-zygotic reproductive isolation mechanisms?

A
  1. zygote death
  2. F1 hybrid sterility (the first offspring produced by two species cannot produce kids of its own)
  3. F2 fitness sterility (the first offspring’s offspring can’t have kids)

an example of a hybrid is mules (mix of horse and donkey). They cannot reproduce on their own and need a man made source to breed them.

51
Q

What is allopatric speciation? List some examples

A

Allopatric speciation is the first step toward reproductive isolation. It occurs when a single population becomes subdivided by geographical barriers like mountains, water, natural disasters and habitat fragmentation

52
Q

Name an example where genetic drift and allopatric speciation occur?

A

When two groups of a the same species are living on an island together (A & B), then 2 members of group A (that happen to have a rare gene) fly off into a different island by chance and start reproducing and making more species with that rare gene. Then they experience natural selection which favours individuals who are better suited to the climate and food of the island.
- After many generations, the island species (A) becomes reproductively isolated from species (B). and Speciation occurs, therefore A & B won’t be able to mate

53
Q

What is Sympatric speciation?

A

when subgroups can form within a continuous habitat (no physical barriers). Occurs typically when individuals of a subgroup stop mating with the members of the larger population therefore, producing their own species

54
Q

List 5 Steps of how species can become reproductively isolated?

A
  1. A single population becomes subdivided either geographically/physically or within a habitat
  2. More likely to now mate with the members in the subgroup therefore gene flow is reduced (pre and post zygotic isolation)
  3. Microevolution is independently working on the subgroups (natural selection, genetic drift, mutation, non random mating)
  4. The separated groups eventually evolve and adapt to their local environment and they become different in form, physiology, or behaviour which results in complete reproductive isolation
  5. speciation has occurred
55
Q

What are three outcomes of hybrid zones? And what are hybrid zones?

A

Hybrid zones are the degree in which a species can mate with another species after they split off from each other.

  1. initially the species are hybrid, but overtime the hybrids die out and the two species become completely separate and unable to reproduce with each other
  2. Initially they are not hybrid, but then all reproductive barriers break down and the two species are able to freely reproduce and fuse back into one species
  3. Initially they are hybrid and the hybrids continue to exist and their fitness is okay but not as good as within species of parents.
56
Q

What are 3 factors that reinforce reproductive barriers ?

A
  1. Natural selection reinforces reproductive isolating mechanisms, by favouring genes that cause individuals to avoid mating with hybrids (increases reproductive isolation and leads to speciation).
  2. When two populations come back into contact:
    - if reproductive isolation is complete –> speciation
    - if reproductive isolation is incomplete –> hybrids
  3. If the hybrids had lower fitness than either parental form, selection would act to increase the reproductive isolations so that each species would not mate with each other anymore
57
Q

What occurs during ‘fusion’?

A

fusion is the weakening of reproductive barriers to promote hybrids. This is usually because the hybrids have a better chance of living and adapting than the parent species

58
Q

What are 2 paces of evolution? Describe each

A
  1. Gradualism: occurs gradually and gives rise to a new species over many generations
  2. Punctuated equilibrium: Periods of stasis punctuated by drastic change (sudden and rapid change), followed by long periods of stasis where nothing changes. The rapid period of change gives rise to speciation.

BIO 108 (Hunt Made These :)) (32 decks)

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