Define Biological Evolution
The change in properties of groups of organisms over the course of generations
“Descent with modification”
What are groups of organisms and what does this imply (2)?
Groups of organisms refer to the “population” however extends beyond the individual to the generation
- variation - individuals are not all alike
- heritability - offspring tend to resemble their parents
What are the two implications of evolution and what do they form the basis of?
Variation and Heritability - which forms the basis of genetic differences.
What is meant by the point populations diverge?
That populations have subdivided meaning several populations are derived from a common ancestral population and a universal common ancestor
Who’s philosophy was incorporated into Western Philosophy? and what was this idea?
Plato and Aristotle and the shared philosophy of essentialism
Define essentialism
The idea that every entity has a set of attributes necessary to its identity and function - variation is accidental imperfection
Expand the idea of essentialism (immutable)
The imperfect realization of the true species exists in variation in nature - these are immutable (unchanging over time)
What does the “Ladder of Nature” or “Great Chain of Being Refer” to?
That “order is superior to disorder” meaning there would be a graduation from inanimate to more animate beings - the reflection of a divine plane where there is either a loss or gain in complexity
What did Linnaeus contribute to evolution? but did not change from the old ideas about it.
18th Century established worldwide classification and naming of species
Species were still thought of being immutable
What paved the way for evolutionary thinking? (Pre-Darwin)
Observations that suggest organisms change over time
What were the observations that suggest organisms change over time? (3)
- Comparative anatomy and embryology
- Geological observations of sedimentary rock (stratigraphy)
- fossil organisms distributed in rocks
Who was Lamarck and what did he propose?
- before Darwin (1774-1829)
- believed species were NOT immutable and undergo change
- inheritance of acquired traits
What did Lamarck refer to with his idea of Inheritance of Acquired Traits?
- that offspring placed in different environments undergo changes which are shared with their offspring through inheritance
- ex. giraffes and their longer necks
Who was Alfred Russel Wallace?
- independently came up with the idea of Natural Selection at the same time as Darwin
- 1858 coauthored a presentation to the Linnaean Society of London
Who and when was Charles Darwin?
- 1809-1882
- on the Beagle from 1831 to 1836
- inspired by Thomas Malthus essay
What was the title of Darwin’s book?
On the Origin of Species by the means of natural selection, or the preservation of favoured races in the struggle for life
Explain the first two observations and the one inference for Natural Selection.
- Individuals typically produce far more offspring than are needed.
- Most populations are fairly constant in size
- only some offspring can survive the struggle for existence
Explain the second two observations and the other two inferences from them for Natural Selection
- Individuals are all different
- Individuals trait are largely heritable (passed on to offspring)
- Individuals with favourable traits tend to survive
- Individuals with favourable traits leave the most offspring, which will change the population over time
What does Darwin’s Theory of Descent refer to?
That all species, living and extinct, had descended from one or a few common ancestors
- they are very similar at first but accumulate differences over time
What is separates Darwin and Lamarck’s view for the conception of evolution?
Lamarck believed common ancestry plays no role (the inheritance of acquired traits) - where individual organisms change
Darwin believed in the evolution from a common ancestor
How does Darwin summarize Natural Selection in the Origin of Species?
If variations are useful, thus individuals thus characterized with these will have the best chance of being preserved in the struggle for life
With the principle of inheritance, these individuals will produce offspring similarly characterized - the principle of preservation
There are 5 examples of Evolution, what are they?
- Fossil record - similar and not identical forms in rocks compared to species observed today
- Embryology and development; and vestigial structures and organs (presence of useless structures)
- Homology of structures - suggestion of common ancestors
- Genetic code underlines molecular similarities of all organisms
- Real time observations - antibiotic resistance
How does Gregor Mendel’s work link with Darwin’s?
(1822-1884)
- he proposed the particulate theory of Genetic Inheritance
How can inheritance work but still maintain variation in the population?
- what idea counters this thought?
- that through inheritance offspring should “funnel” towards stock model where all individuals are phenotypically similar
