History of genetics and evolution Flashcards
Define microevolution.
Intraspecific variation, i.e. looking at diversity between populations of the same species.
Define macroevolution.
Interspecific variation across geological time, the diversity of life as a whole.
Why is evolution still relevant to modern life?
Many pathogens/pests are evolving rapidly and this will affect us.
Plato and Aristotle created the ‘theory of forms’. What does this mean?
Our world is an imitation of the pure and unchanging world of forms.
According to the theory of forms, what are species referred to as?
Essences - every member of a species is an imperfect copy of the essence of that species.
What was Lamarck’s theory?
‘The theory of acquired characteristics’, whereby an organism accumulated changes over its lifetime that it then passed on to the next generation.
What was Darwin’s theory?
‘The theory of natural selection’, whereby selection eliminated individuals that were maladapted and those that were successful passed on their characteristics to the next generation.
Weismann did not agree with Lamarck’s theory. Why?
The germ line cells are set apart from somatic cells early in development, thus changes accumulated over an organism’s lifetime cannot be passed to its offspring.
What was Mendel’s theory?
‘The theory of particulate inheritance’, the hereditary materials exists in 2 (particulate) copies. These separate in the gametes and one is inherited from each parent.
What is the theory of blending heredity and why is this flawed?
The hereditary material is in liquid form (‘mixing of the bloods’). Would mean that characters are diluted and thus lost down the generations.
Why does the existence of dominant and recessive alleles allow for diversity, when ‘mixing of the bloods’ does not?
It allows for the preservation of existing and creation of new phenotypes instead of dilution.
By what kind of mutations did Mendel think new species were created?
Macromutations, large-scale changes.
At what kind of rate did Darwin think change accumulated?
Gradual.
What is the ‘Neo-Darwinian theory of modern synthesis’?
Darwin’s theory of natural selection coupled to the practicalities of Mendel’s particulate theory.
What did Fisher and Haldane investigate?
The effects of selection on changes in gene frequency.
