Hostory Of The Evolutionary Theory Flashcards
What is evolution?
Systematic change through time (biological and cultural)
Describe Darwinian thinking
- population not individual is the unit of evolution
- variation is the norm
- four evolutionary forces
Describe pre Darwinian thinking
- world was static and unchanging
- world was the product of grand design
- typological thinking was the norm
What were the beliefs pre Darwin of the natural world
- essentialism
- great chain of being
- Catastrophism and unfenitarianism
- transformational evolution
What is essentialism
- traced to Plato
- fixed forms exist perfect and unchanging in eternity
- differences perceived as accidents
- was elaborated on be Aristotle using the differences to arrange into single line
What is the genetic chain of being?
- all organisms in one long chain (no gaps, extinctions etc)
- arranged from worst to best (including different humans)
Describe Carolus Linnaeus
- created modern biological taxonomy (classification)
- essentialist (fixed number of species)
- didn’t suggest evolution but recognized similarities (humans, apes)
- believed humans a part of nature
Who is Georges Cuvier?
-pioneer in palaeontology
-first important excavations of fossils in sene river basin
-“catostophism”
~fossil species wiped out a replaced
~never though species came from on another
~ problem was made creation look disorderly
Who was Charles Lyle
-stimulated interest in informitarianism
~ natural forces constantly shaping and reshaping earth
~Change in organisms
~late 19th century replaces catastrophism
Who was jean baptistery de Lamarck
- did not believe that organisms existed fixed and unchanging
- explored mechanisms to explain how biological change could occur
- once a species existed it could Change over time to become more perfectly suited to its environment
- developed idea of transformational evolution
- noted fossil species resembled living species, suggest were ancestors
- fossils looked different because influenced by different climate/ geography
What were the two transformations Lamarck believed in
- law of use and disuse: Features of an organism strengthened by use/ weaken disappear without use
- law of inheritance of acquired characteristics: changes occurring in an organisms lifetime could be passed to offspring
What did Lamarck believe about fossils?
- resembled living species, could be ancestors
- looked different because of different climate and geography
- demonstrated species could vary over time
Describe Darwin’s background
- Lyell - principles of geology 1831: geology and uniformitarianism
- observed change - artificial selection, breeders and gardeners (Darwin pidgins)
- competition for scarce Resources
Who was Thomas Malthus and what did he contribute?
- English clergyman and political economist
- concern was decline of living conditions in the 18th century England
- nature reproduces itself geometrically
- resources increase arithmetically
- conflict
- famine and poverty
What were Darwin’s contributions to the theory of natural selection?
Variational evolution.
- biological variation is present in any given population
- variants best suited /adapted to current environment have greater chance of surviving/ reproducing
Who was Gregor Mendel and how did he contribute to the theory of natural selection
- genetics
- Austrian monk/amateur botanist (pea plants)
- contributed to the concept of transmission of traits in families
What are the Mendelian models for heredity?
- characteristics that we observe = phenotype
- inferred that is influenced by genetic make up (genotype)
- genetics emerged through the study of phenotypes (not chromosomes/genes)
What did we learn after Mendel?
- genes = segments of DNA serving as the building blocks of proteins
- Alleles = alternative forms of a gene at same locus on homologous chromosomes (23 pairs)
What are the factors that produce and redistribute variation?
- mutation
- gene flow
- random genetic drift
- founder effect
- bottle neck
What is mutation?
- change in genetic material
- basic creative force in evolution - only way to produce truly new variation
- rare and have little effect unless paired with natural selection
What is gene flow?
- Movement of genes/ alleles from one populations to another
- migration and interbreeding
- geographic (is land) and cultural factors can play a role
- tends to decrease genetic differences between populations
What is random genetic drift
- has potential to increase differences between populations
- genes/ alleles become more/less common due to small population size and sampling
What is founder effect
- migration- founding group and descendants carry a small fraction of Alleles
- restricts gene pool for next generation
What is a bottleneck
Small population and there genes survive high mortality period in population (war, plague, natural disaster etc)
What is natural selection?
- slow gradual process: reshapes population allele (gene frequencies
- 2 principles: survival, and reproduction
Who is Karl landstamer and what did he discover
- was Austrian physician
- reported on ABO blood group system
- uses mode of Mendelian inheritance
How many Alleles are in the ABO blood type and which ones are dominant?
3
A/B are co-dominant
What do global patterns indicate?
- clinical distributions (small variations across regions)
- distinct pockets (very high/low)
How do we interpret the global distribution of ABO blood type
- mutation
- gene flow (movement and interbreeding of people)
- random genetic drift
- natural selection (small pox)
What is small pox?
- variola virus
- moves easily from person to person via droplet transmission
- mortality up to 30%
- surface antigens look like antigens on blood type A red blood cells
What is evolution
A process - dynamic series of events the ultimately change the biological constitution of a population
What is micro evolution? Macroevolution?
- Micro- small scale changes (gene/allele frequencies) usually over generations
- macro- large scale change (fossils) typically associated with speciation
