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Lecture 3

BGYB51H3 Lecture 3 Notes Sep 17 2009

Biological Sciences
Course Code
Maydianne Andrade

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BGYB51H3 Lecture 3 Notes
-through natural selection, species can change in characteristics through time
-looking at species of plants and animals, humans domesticated for their own use
-domestication through artificial selection causes species to evolve (e.g. dogs from wolves)
-social evolution is imposed on offspring and pets through selection of certain behavioural traits
-social competence through communication is selected in dogs
-many varieties can derive from a single ancestor
-agriculture required plants through domestication by artificial selection of a mustard plant to
yield certain vegetables
-artificial selection does require variation, heritability, and different variants producing
different numbers of offspring
-artificial selection involves an agent of selection which is the human
-environment is the agent of natural selection
-artificial selection involves conscious intent and a goal
-natural selection involves no conscious intent or goal
-different types of descendants from one common ancestor are possible
-geological evidence came from scientists who may have been unaware of evolution but
wanted to learn patterns of rock in strata
-characteristics of layers were observed and compared through fossils found
-order of deposition is inferred through relative dating or radiometric dating
-new species appear continuously through time
-organism in one time period may be found in other periods
-there is a time period of species appearance
-there is a progression of complexity in the fossil record
-law of succession involves geographic patterns in which living organisms in one area are similar
to the fossils in that area
-environment changes over time cause extinctions on Earth
-an ancestral form involves certain traits in which some survive during a split in lineages while
-fossilization is a rare event and not all fossils are found yet
-species that have descended with modifications have spread across Earth through dispersal
-biogeography is the study of the pattern of distributions of life on Earth
-species in oceanic islands dispersed from nearby continents through flying
-fewer species on islands than continents
-island species such as birds, bats, e.t.c are good dispersers
-human introduced animals to the islands flourish
-the biota of islands are descendants from ancestors in the nearest continent
-species evolve to adapt to local conditions and are endemic
-adaptation is defined as evolving to fill empty niches
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