Population Genetics 1 Flashcards
facets of evolution (5)
- speciation and extinction
- origin and spread of new genetic variants
- gradual change over a long period of time
- rapid changes in response to changing conditions
- changes in the genetic pool
what is evolution
- CHANGE in the form/behaviour of organisms between generations
evolution
- described by Darwin
- descent with modification
evolution
- described by Futuyma and Kirkpatrick (4)
origin and alteration over generations of:
- ideas within society
- frequencies of genotypes within populations
- proportion of differentiated populations within species
- proportion of species with different traits within a lineage
how can evolutionary change occur? (2)
- chance bursts of reproduction, deaths or mutation
- natural selection
what does natural selection explain?
- explains how undirected change can improve the match between an organism and its environment
natural selection
- process whereby some individuals contribute more offspring to the next generation as a consequence of their carrying a trait(s) favourable to survival and reproduction
when does evolution by natural selection occur? (3)
occurs whenever
- individuals vary in some trait (VARIANCE)
- individuals with some trait values are more likely to live/reproduce (SELECTION)
- parents have offspring with similar trait values (HERITABILITY)
Aristotle (3)
- greek philosopher
- examined natural world for evidence of divine order
- created the Scale naturae (“Chain of Being”)
Scale naturae (“Chain of Being”) (3)
- hierarchical arrangement of forms
- species arranged linearly along a scale: god -> man -> mammals -> egg-laying animals -> insects -> plants -> non-living matter
- formed the basis for the western belief in the fixity of species, each of which has a typical form
Carolus Linnaeus (4)
- classified organisms according to binomial system, giving each a SPECIFIC and a GENERIC name (Genus species -> eg. Homo sapiens)
- proposed a nested system of relationships (as opposed to the Scale naturae)
- recognized fundamental difference between interbreeding (within species) and non-interbreeding organisms (non-interbreeding species)
- believed in balance of nature
what are the facets of the modernized Linnaean system? (7)
- generally know
- kingdom
- phylum
- class
- order
- family
- genus
- species
balance of nature (3)
- from Carolus Linnaeus
- each species has its place in a divine plan
- species would not chance or go extinct
- eventually acknowledged LIMITED formation of new species by hybridization
Comte de Buffon (2)
- beliefs
- believed Linnean hierarchy reflected common descent (dégéneration) with divergence over time
- believed that change only happened within families
common descent/dégéneration (3)
- from Comte de Buffon
- physical environment somehow changes organic particles
- new species form when animals migrate to new environments
- new environment then causes changes to the species
change only happens within families (2)
- from Comte de Buffon
- each family conforms to an internal mold
- species can change over time but are limited to their original mold at the family level
Erasmus Darwin (4)
- relation to Charles Darwin
- wrote…
- beliefs (2)
- Charles Darwins’ Grandfather
- Wrote Zoonomia/The Laws of Organic Life
- believed organisms constantly attempted to improve themselves by adapting to their environments (transformism/transmutation) but did not know the mechanism
- believed that all life consists of “one living filament” connecting all libing forms to a common ancestor
Jean-Baptiste Lamarck (3)
- theory of “transformism”, which was incorrect
- believed that at the base of hierarchy, “simple” organisms constantly arise by spontaneous generation
- suggested a mechanism for organic progression in Philosophie zoologique
theory of “transformism”
- organisms progress through a hierarchy of ever-more-advanced forms (almost a Scala naturae in reverse)
suggested mechanism for the theory of “transformism” (2)
- first law: use or disuse of a structure within a structure leads to its development or diminishment
- second law: these acquired characters can be passed on to offspring
suggested mechanism for the theory of “transformism” (2)
- example
- muscles shrink due to no use (diminish) OR muscles growing due to lots of us
- large/small muscles can be passed to offspring
Thomas Malthus (2)
- principle of overproduction: wrote “An Essay on the Principle of Population
- major of influence on Darwin and Wallace
principle of overproduction from “An Essay on the Principle of Population (3)
- from Thomas Malthus
- most organisms produce far more offspring than can possibly survive
- even when resources are plentiful, populations tend to grow geometrically until they outstrip their food supply
- poverty, disease, and famine are inevitable, leading to a “struggle for existence”
Charles Lyell (3)
- “uniformitarianism”
- his Principles of Geology was a major influence on Darwin and Wallace
- ideas on Earth was applied to his views on the living world
uniformitarianism (2)
- from Charles Lyell
- earth is subject to gradual and continuous change, but without progress or development
- earth remains in a steady state (slow building of volcanoes from earthquakes is also worn down by erosion at the same time)