Topic: darwin

Question 1

What are theories on origin of species pre-Darwin?

Answer 1

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

Question 2

Give the Scala Naturae

Answer 2

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

Question 3

What is Carolus Linnaeus’ theory of species origin?

Answer 3

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

Question 4

What is Lamarck’s hypothesis of evolution?

Answer 4

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

Question 5

Why did Darwin begin researching?

Answer 5

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

Question 6

Define uniformitarianism

Answer 6

• Mechanisms of change constant overtime

Question 7

What influenced Darwin’s ideology?

Answer 7

• Lyell’s principle of uniformitarianism + study of fossils

Question 8

Describe Darwin’s theory on species origin

Answer 8

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

Question 9

Define evolution

Answer 9

• Change in inherited characteristics of biological population over generations

Question 10

2 main points of Darwin’s theory

Answer 10

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

Question 11

Define natural selection

Answer 11

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

Question 12

What is explained by Darwin’s theory?

Answer 12

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

Question 13

Define unity of life

Answer 13

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

Question 14

Define diversity of life

Answer 14

• Differences between organisms

Question 15

Define tree of life

Answer 15

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

Question 16

Define artificial selection

Answer 16

• Process of modification by humans = select + breed individuals with desired traits

Question 17

Define adaptation

Answer 17

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

Question 18

Give Darwin’s 2 observations of NS/adaptation

Answer 18

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

Question 19

Give Darwin’s 2 conclusions of NS/adaptation

Answer 19

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

Question 20

Explain how traits are effected by NS/adaptation

Answer 20

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

Question 21

Describe NS/adaptation in thalassaemia

Answer 21

• 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

Question 22

What scientific data supports evolution?

Answer 22

• Direct observation
• Homology
• Fossil record
• Biogeography

Question 23

Describe direct observation of evolutionary change

Answer 23

• 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

Question 24

Describe NS in response to introduced plant species

Answer 24

• Soapberry bugs use beaks = feed on fruit seeds
• Southern Florida = larger fruit = longer beak
• Central Florida = smaller fruit = shorter beak
• Beak size evolved in population based on introduced plants

Question 25

Describe the evolution of drug-resistant bacteria

Answer 25

- 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

Question 26

Describe methicillin

Answer 26

- 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

Question 27

Describe homology of evolutionary change

Answer 27

- Similarity between different species resulting from common ancestry - Anatomical homologies = similarities in anatomical features - Molecular homologies = similarities in genetic material

Question 28

Give examples of anatomical/molecular homologies

Answer 28

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

Question 29

Explain the evolution of an appendix

Answer 29

- 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

Question 30

Define convergent evolution

Answer 30

- 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

Question 31

What evidence do fossil records provide?

Answer 31

- Extinction of species - Origin of new species - Changes within group over time - E.g. transition of marine mammals/cetaceans from land > sea

Question 32

Define biogeography

Answer 32

- Geographic distribution of species = evidence of evolution - Pangaea separated by continental drift = species distribution + can predict where they evolved from

Question 33

Define endemic species

Answer 33

- Not found anywhere else in the world - E.g. islands have many = closely related to nearest mainland species adapted to new environment