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Flashcards: EVOLUTION
Species
a group of organisms of common ancestry that closely resemble each other and can interbreed and produce viable offspring
Selection pressure
external agents which affect an organisms ability to survive in a given environment
Natural mutation
mutation which does not affect amino acid can be detected using genome analysis
Lethal mutation
unfavorable phenotypic change leading may lead to death
Fixed mutation
result in a favorable phenotypic change advantage
Convergent evolution
species from different evolutionary branches may resemble each other due to similar ecological roles
Divergent evolution
the diversification of an ancestral group into two or more species in different habitats
Analogous structures
different structures with similar function
Homologous structure
same structures different function
Adaptive radiation
rapid diversification
Gene flow
transfer of genes from one population to another of the same species as by migration or the dispersal of seeds and pollen
Genetic drift
the process of change in the genetic composition of a population due
Evolution
change in genetic frequency over time
Speciation
refers to the process whereby new species are formed (occurs with lack of gene flow)
Allopatric speciation
geographically separated become subject to different selective pressures
Sympatric speciation
new species forms inside population (no geographical barrier)
Prezygotic
no sexual attraction leading to no mating
Reproductive isolating mechanisms
prevent successful breeding between different species (barriers to gene flow)
Archaeology
the study of ancient civilizations
Anthropology
the study of human sciences
Paleontology
the studies of fossils & evolution of life on Earth
Biological evolution
change in gene pool over time of species
Micro evolution
changes in gene frequency of a population from one generation to the next
Macro evolution
decent of a different species from a common ancestor
Biogeography
barriers preventing species from intermingling
Comparative biochemistry
the molecular structure of most living organisms is similar
Comparative embryology
the development path for many organisms is very similar
Vestigial structures
structures which are still functional in some organisms but have minimal use
Erasmus Darwin
wrote zoomania believed organisms could pass on acquired characteristics
Jena Baptist limerick
wrote philosphie zoologique believed change happened from use and disuse and that acquired characteristics where passed on
Charles Darwin
conceived the idea of natural selection
Alfred Wallace
independently conceived the idea of natural selection
Artificial selection
selection of traits to breed (mimics natural selection)
Adaptive radiation
process where species rapidly evolve to fill ecological niches
Evolutionary tree
a diagram which represents the pattern relationships between groups of organisms (branch length: time)
Stasis
not changing for a very long time
Cladogenesis speciation
parent species splits into two distinct species (absence of transition fossil)
Anagenesis speciation
changes are gradually accumulated; when enough is accumulated the species is distinct enough that it can be labeled a new species
Clade
a life form group consisting of a common ancestor and all it's descendant
Phyletic gradualism
evolution occurs uniformly and steadily
Punctuated equilibrium
in stasis until an event causes rapid evolution
Genetic drift
the process which produces random changes in gene frequency
Mutations
changes in nucleotide sequence allowing microevolution to take place
Neutral mutations
change in nucleotide sequence but not protein it codes for
Lethal mutations
causes an unfavorable phenotypic change which may cause death
Fixed mutations
causes a favorable change in the phenotype giving an advantage to the individuals in the population with this change
Gene flow
the movement of genes between populations
Population
a group of individuals of the same species occupying the same area
Speciation
formation of a new species from an old one
Inbreeding
mating with closely related individuals of the same species reducing the gene pool
Outbreeding
the mating of unrelated individuals of a species
Founder effect
an event when a small number of individuals carrying a fraction of the populations genetic variation are founders of a new society elsewhere
Population bottleneck
catastrophic events kill of parts of the population causing the founder effect
Bipedalism
walk on two legs
Australopithecus anamensis
4mya hominid with first signs of bipedalism
Australopithecus africanus
code named Mrs. Ples ; Taung child ; Little foot lived in South Africa
Australopithecus sediba
lived in South Africa may be a transitional species (walks upright & precision grip)
Homo species
used tools appeared 2mya human like characteristics
Homo habilis
Large brains code named Handy man due to tool use
Homo neanderthalaensis
used hand axes (ancestor of Neanderthals)
Homo erectus
used advanced tools
Homo sapiens
cave paintings, burials spread throughout the Earth
Oldowan tool culture
oldest tools used by homo habilis used to cut meat from bone
Acheulian tool culture
more advanced used by homo erectus hand axe pics & cleavers
Mousterian tool culture
used by Neanderthals included flakes scrapers and points
Ardipithecus
ape like organism with change in forum magnum placement
Ardi
complete female skeleton of Ardipithecus ramidus
Australopithecines
bipedal organism with both human and ape like characteristics
Australopithecus afrarensis
lived in trees and on ground ; short with small brain (Lucy)
Australopithecus Africanus
both human and ape like characteristics found in Gauteng (Phillip Tobias & Ron Clarke)
Australopithecus Sediba
transitional species code name Karabo (Lee Burger)
Homo ergaster
ancestor of modern humans ; human like characteristics
San people
descendants of the worlds earliest diversification event
Multiregional theory
suggests all humans evolved from homo erectus which was dispersed ; small amount of gene flow prevented speciation
Out of Africa theory
suggests homo sapiens arose in Africa and migrated due to climate