ANHB1101 Lecture Notes - Lecture 3: Carl Linnaeus, Hyundai Genesis, Genetic Drift
17 Jun 2018
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Evolution summary- using unit outline summaries each component
A. Define biological evolution
• Inherited genetic change in a population over time
B. Understand pre-Darwinian ideas on evolution
• Early Greek philosophers: recognised fossils as evidence of former life but failed to
establish own evolutionary concept
• Genesis: required no mechanism explanation
• Great chain of being: life as a hierarchical sequence - 18th and 19th century opinions
divides fixity of species vs change of species
• Carolus Linnaeus( fixity of species) - species were fixed and unchangeable and were
created originally as we find them today ( no evolution)
• Jean- Baptiste de Lamarck- change of species , scale of nature( species move up
heirarchy, inheritance of acquired characteristics
o Inheritance of characteristics ( Lamarck)
• Environment change led to animals developing new changes to meet new
demands of the environment
• Changes led to alter animals metabolism
• New body parts/ characteristics appeared to meet new requirements
• New characteristics are passed on to offspring's
C. Describe Darwin & Wallace's theory of evolution by natural selection
• Conditions for evolutionary change
1. Intrinsic increase in number of individuals within species
2. Competition for limited resources
3. Survival of a few
• Mechanism of evolutionary change
• Natural selection: those individuals with more favourable features would survive far
better than competitor passing on to their offspring those advantageous characteristic
4. Understand the role of inheritance and variation in natural selection.
• Inheritance is the transmission of traits from one generation to the next ( dominate and
recessive traits determine which traits are visible and which are not)
• Variation(reproductive fitness, mutation, selection pressure
• Understand that there are four evolutionary forces: mutation, natural selection, gene
flow and random genetic drift
• Mutation: spontaneous error in DNA replication leading to a heritable change in
individuals' genome - not a change in genetic code
• Random genetic drift: can be as a result of natural disaster
• Gene flow ( gene mutation): transfer of genes/ alleles from one population to the next.
• Natural selection: those individuals with more favourable features would survive far
better than competitor passing on to their offspring those advantageous characteristic
• Understand fitness and its components
• Survival of the fittest
• Survival + reproductive fitness- surviving/ living long enough to reproduce.
• More offspring= better fitness
• Selection: describe the following, biotic & abiotic selection pressures, natural and
artificial selection and sexual selection.
-Biotic factors: competition, predation, disease
• Abiotic factors: climate, topography, habitat
• Natural selection
o Stabilising selection: selects against extreme and shifts average over time
o Directional selection: phenotypic character shifts in one direction- acts on 1
extreme
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