How did evolutionary theory come into life
- Linnaeus started to classify plants and animals. Ppl started to wonder: how to define species, how did diversity emerge
- extinction: fossils
- biology gradualism: stratigraphy: species emerge and disappear, comparative anatomy (fossils, bone)
- geology gradualism: LYELL and uniformitarianism: continuation of small cumulative changes
- breeders of domestic animals, comparing embryos
- MALTHUS: struggle for resources (critical point)
Why was the Beagle journey important
Darwin observed the differentiation of species. Some organissms are poorly designed, contradicting religious view.
- fossils Patagonia (extinct animals with similar anatomy current animals)
- geographical distribution of ostrich: closely related species didnt inhabit same area
- animal life Galapos islands, mocking birds different from island to island
- natives from Tierra del Fuego were brought to England and ‘educated’, -> humans are all the same
Herbert Spencer
Introduced term survival of the fittest
Social Darwinism
Criticisms on evolution theory
- dilution problem: how do variations get passed on without disappearing in the population (Fleemin Jenkin0
Solved by modern genetics (neodarwinism)
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What is mendels law and how is it related to dilution problem
Genes do not get diluted, they get passed on (according to probability laws) to offspring, and the occurance of dominant and recessive genes then determines the phenotype. Adaptive genes thus survive in the population, the proportion of individuals with the gene will gradually rise
What are the 4 factors in the evolution theory
- random variation due to transcription error in DNA replication for the unborn young
- inheritance
- selection
- time
2 ways that new species can emerge thru evolution
- allopatric speciation: due to geographical separation and long time no interaction, and difference in what features are adaptive to environment
- sympatric speciation: behavior of mutated form is different and results in low interaction between animals, leading to divergence (mating, food habits that are more adaptive to certain environment)
Evidence NOW for evolution
- baceterial resistance to antibiotics
- more knowledge on fossils
- human genome project to map out genotype, same genes in sequence = common ancestor. DNA sequencing. Longer speciation difference = more difference DNA
Common misunderstandings of the theory
- evolution is not in a given direction, genes do not know what is better. Not Lamarckian (not due to experience)
- organisms dont become better or stronger, they only survive if they are adaptive to the environment at that time and place, this situation can change at any moment.
- variations are random
- does not explain origin, does not come up with evolution, but explains how it happens
Implications evolutionary theory for psychology
- Evolutionary psychology, not as a separate movement, but as a lens to view all psychological mechanisms in. Why did this feature evolve? Why is it adaptive?
- Viewing psychopathology as the failure of evolved coping mechanisms is helpful for treating and research
- Lead to comparative psychology: use of animal models, bc there was the idea man could be compared to animals now. (common ancestor)
- began investigating individual differences: if things are inheritable, which features are better and who has them? what makes some more succesful than others?
- became more biological: the brain is what makes humans different, if it evolved biologically, then biology can answer questions about the mind.
The premises of evolutionary psychology
- The brain, psychological mechanisms and behaviour have evolved that way.
- Mechanisms evolved bc they had adaptive purpose (eg for surival or reproduction)
- This adaptive purpose sometimes doesnt work with our modern environment anymore, causing problems
Why did social darwinism happen
People were worried natural selection didnt happen anymore due to humanitarianism, medicine etc
Discovered there was actual change in birthrate lower vs higher class
- Positive view of state, thought state should interfere
Alfred Russell Wallace
- Co discoverer of evolution theory
- Thought selection of qualities like altriusm happened and caused people to care for weaker ppls, so that at some point evolution would stop.
- thought Caucasian race was superior and would outlive the others
- from poor family
Galton 1870
First major proponent eugenics bc thought that personality traits were inherited, tried to test for intelligence (psychometrics) to show it was inherited but failed.
How should society deal with the issue of selection?
- positive eugenics: making sure strong ppl reproduce more
- negative eugenics: sterilising or killing weak people
- Lamarckian view: active adaptation so social reform would help.
Proponents of Intelligent Design and arguments
Tries to teach controversy about evolution
William Paley: natural theology and the analogy of the watch and the eye. It looks so complex it must have been designed by allknowing thing.
Irreducible complexity: if you remove a part it doesnt work anymore
Specific complexity: quantification that says the probability of such complexity being natural is very low
Different forms of selection
- Artificial selection (by Man, breeding etc)
- Sexual selection
- Natural selection
Aristotle’s causes
- Final (teleological, goal and purpose)
- Material: because of what its made of
- Efficient (mechanistic: it is that way because of its parts and how they work)
- Formal: the way it is arranged
Problem with final causation?
Its a posteriori: requires a foreseeing being (God)
Example: ozone layer bc it protects us (no..)
Gradually replaced by efficient causes as mechanism rose
Lamarck
- Active evolution: organisms strive to better themselves
- Principle of use and disuse
- Principle of inheritance of acquired characteristics
John Herschel
Influenced Darwin, believer in evolution
Herbert Spencer 1870
Used Darwins ideas of natural selection for society -> social Darwinism. Believed in an end point of evolution: weak persons will evolve in strong persons. Thus support for competition
