Topic 10: darwin Flashcards

(31 cards)

1
Q

What are theories on origin of species pre-Darwin?

A
  • Traditional = earth inhabited by unchanging species
  • Aristotle = species are fixed
  • Old testament = species individually designed by God = perfect
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2
Q

Give the Scala Naturae

A

1) God
2) Angels
3) Humanity
4) Animals
5) Plants
6) Minerals

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3
Q

What is Carolus Linnaeus’ theory of species origin?

A
  • Organismal adaptation = evidence God designed each species for specific purpose
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4
Q

What is Lamarck’s hypothesis of evolution?

A
  • Species evolve via use/disuse of body parts = inheritance of acquired characteristics
  • Not supported by scientific evidence
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5
Q

Why did Darwin begin researching?

A
  • Doubts about permanence of species
  • Went on 5-year world-wide trip
  • Interest in geographic distribution of resembling species in different regions of Galapagos
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6
Q

Define uniformitarianism

A
  • Mechanisms of change constant overtime
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7
Q

What influenced Darwin’s ideology?

A
  • Lyell’s principle of uniformitarianism + study of fossils
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8
Q

Describe Darwin’s theory on species origin

A
  • Published in 1859
  • Evolution = descent with modification
  • Mechanism = natural selection
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9
Q

Define evolution

A
  • Change in inherited characteristics of biological population over generations
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10
Q

2 main points of Darwin’s theory

A

1) Descent with modifications:
- Current species descend from ancestral species = common ancestor
- Modifications happened over generations
2) Natural selection is mechanism of evolution:
- Individuals with favorable traiys = likely to survive + reproduce = survival of fittest
- Traits accumulate over populations = higher population with better traits

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11
Q

Define natural selection

A
  • Process that occurs = populations’ heritable variation exposed to environmental factors
  • Factors favor reproductive success of some over others
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12
Q

What is explained by Darwin’s theory?

A
  • Adaptations of organisms
  • Unity + diversity of life
  • Evolution is responsible for unity + diversity
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13
Q

Define unity of life

A
  • Similarities between organisms
  • All life connected via long evolutionary history
  • E.g. related organisms = similar anatomical features
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14
Q

Define diversity of life

A
  • Differences between organisms
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15
Q

Define tree of life

A
  • Natural selection can enable ansestral species = split into 2+ descendant species
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16
Q

Define adaptation

A
  • Evolutionary process = enhance fitness + survival of individual in own environment
  • Adaptation + origin of new species = closely linked
17
Q

Give Darwin’s 2 observations of NS/adaptation

A

1) Members of population = vary in inherited traits
2) Species produce more offspring than environment can support = many fail to survive + reproduce

18
Q

Give Darwin’s 2 conclusions of NS/adaptation

A

1) Differences in reproductive success = individuals with inherited trait with higher probability of surviving + reproducing = more offspring
2) Evolutionary adaptations in populations = unequal ability to survive + reproduce = accumulation of favorable traits over generations

19
Q

Explain how traits are effected by NS/adaptation

A

NATURAL SELECTION:
- Doesn’t create new traits
- Selects traits already present in population
ADAPTATION:
- Environmemt determines trait selected/against
- Adaptations vary with different environments

20
Q

Describe NS/adaptation in thalassaemia

A
  • Thalassaemia allele survives in heterozygous carriers in countries = malaria
  • Plasmodium malariae replicates in mosquitoes living in tropical regions
  • Infects RBC = digest haemoglobin
  • Carriers = lower haemoglobin level = more resistant to infection
  • NS favored survival of carriers of allele
  • Therefore having single allele advantageous = protect against malaria in endemic region
  • Heterozygous carriers have protection against coronary heart disease
21
Q

What scientific data supports evolution?

A
  • Direct observation
  • Homology
  • Fossil record
  • Biogeography
22
Q

Describe direct observation of evolutionary change

A
  • NS in response to introduced plant species
  • Evolution of drug-resistant bacteria
  • Evolution of insecticide-resistant mosquitoes
  • Increased survival of thalassaemia carriers when exposed to malaria
23
Q

Describe the evolution of drug-resistant bacteria

A
  • Bacteria = short generation times = 1-3 hrs
  • Rapid adaptive evolution = antibiotic resistance
  • E.g. MRSA = pathogenic strain
  • E.g. Staphylococcus aureus = penicillin/methicillin resistance 2 years after use
  • When exposed to antibiotics MRSA = more likely to survive + reproduce than non-resistant strains
24
Q

Describe methicillin

A
  • β-Lactam antibiotic
  • Binds to + inhibits transpeptidase = responsible for forming peptidoglycan in cell wall
  • MecA gene = gene encodes > protein binds to β-Lactam antibiotic
  • Transpeptidase = stays active in presence of β-Lactam antibiotic = prevents inhibition of cell wall synthesis
25
Describe homology of evolutionary change
- Similarity between different species resulting from common ancestry - Anatomical homologies = similarities in anatomical features - Molecular homologies = similarities in genetic material
26
Give examples of anatomical/molecular homologies
MOLECULAR: - Genes shared amongst organisms = inherited from common ancestor ANATOMICAL: - Vestigial structures = structures that have lost original function over evolution - E.g. appendix = from functional cecum
27
Explain the evolution of an appendix
- Used for digesting leaves by herbivores - Herbivores = long cecum = bacteria to digest cellulose - Ancestors start to eat easily digested food = less reliant on cellulose plants = cecum less needed - Mutation = small cecum = continue to shrink > current appendix
28
Define convergent evolution
- Evolution of analogous features in distantly related groups - Due to groups independently adapting to similar environments - Convergent evolution = no info about ancestry = doesn't mean 2 groups are closely related
29
What evidence do fossil records provide?
- Extinction of species - Origin of new species - Changes within group over time - E.g. transition of marine mammals/cetaceans from land > sea
30
Define biogeography
- Geographic distribution of species = evidence of evolution - Pangaea separated by continental drift = species distribution + can predict where they evolved from
31
Define endemic species
- Not found anywhere else in the world - E.g. islands have many = closely related to nearest mainland species adapted to new environment