W11.2_Evolution

Question 1

Define evolution and how it relates to genetics. Describe the process of evolution.

Answer 1

• Definition: how living organisms developed from earlier forms (can be traced back by using ribosomal protein sequences)
• Nearly all living organisms share same arbitrary genetic codes
• Chromosomal/genetic similarities ≈ evolutionary similarities (genes specify functional products)
• Process: differences in genes -> variation in physical characteristics among individuals -> individuals with characteristics best suited to environment -> more likely to survive, find food, avoid predators, resist diseases -> more likely to reproduce, pass genes to offsprings (vice versa for those poorly adapted)

Question 2

What is the importance and application of evolution.

Answer 2

• Importance: higher biocomplexity, higher complexity of biological systems, larger variation to increase diversity, subject to ongoing modification through chance/adaptation (antibiotic resistance), findings of natural products (antibiotics)
• Application: pathogens/risk of developing diseases/microbial adaptation

Question 3

Explain Darwin’s evolutionary theory. What is its natural theory and how does it relate to the variations in genetic diseases?

Answer 3

• Darwin’s evolutionary theory: common descent -gradual natural selection-> evolution
• (Common ancestors) -> populational change (started from proportions of individuals)
• Key observations of natural selection (driver of evolution)
• Traits are often heritable
• More offsprings are produced than can survive
• Offsprings vary in their heritable traits
• Natural theory: evolutionary changes come from neutral mutations (X useful/injurious) and genetic drift (actually does not contradict Darwin’s theory)
• Variations in genetic diseases: rarity and degree of effect

Question 4

What are the evidences for evolution?

Answer 4

• Fossil record (shows successive evolutionary change according to age, with transitional fossils between species found)
• Hierarchical organisation of life (ex. organelle -> cell)
• Shared features/homology (ex. similar developmental pathways with gil silts and tail in embryos)
• Vestigial structures (ex. wisdom teeth, appendix, tailbone in humans)
• Convergent evolution (same function of morphological features in phylogenetically independent organisms) vs divergent evolution (two groups of same species evolve different traits due to different environment/social pressures)
• Imperfect design
• Geographical distributions
• Direct observations (ex. antibiotic resistance in lab experiments)