BIOL1003 Lecture Notes - Lecture 7: Recapitulation Theory, Venus Flytrap, Hugo De Vries
BIOL1003: Module 1 Evolution
Lecture 5 – Wallace, Haeckel, Weismann and Natural Selection
• How did the Venus fly trap evolve?
o Darwin first can up with the evolutionary pathway
o Genetic sequencing then confirmed his theory
• As well as improving function, Darwin also noted change of function is equally or more
important in evolution
• Sexual selection
o If you look in nature, when males and females look different, males will be
decorated or have weapons
o Used to repel rivals, or attract mates
• Alfred Russel Wallace
o Line between Australian and Asian fauna
• Placental mammals in Asia, marsupials in Australia
• First person to consider conservational biology
• Haeckel
o Invested words like
• Phylogeny
• Ecology
• Phylum
o Created kingdom Protista
o First drew up a tree of life as part of an hypothesis (1891)
• Although this as changed since
o Polygenism (human races evolved from different species) - problems with racism
o Racial classification of humans, eugenics (breeding humans to create the perfect
human)
o "ontogeny recapitulates phylogeny" - that the development of the embryo echoes
evolution (not really true)
o Aspects of scientific theory are problematic - eurocentrism, take science and make it
political
• August Weismann
o Pangenesis - allowed for the inheritance of acquired characteristics
• Lamarck
o That usage affected inheritance (giraffes stretched their necks, hence the long
necks) - not true
o Invented the word biology
o Darwin sort of took both sides with usage and inherited traits
o Inheritance of acquired characters seems incorrect
o Some papers come out supporting this theory, usually these contain errors or
omissions
• Is giraffe evolution a case of sexual selection or completion (with other giraffes and with
other animals like elephants, especially in crucial periods)
• Where did variation come from
o Mutation in DNA
o Weisman - germ cells
o Theodor Overi
o Hugo de Vries - pan-genes = genes, mutations
• Unsolved problem for Darwin: bending inheritance
o Traits of offspring are blended in an offspring of two parents
o Darwin thought of continuous traits
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