Buffon’s Law
“environmentally similar but geographically isolated regions have distinct assemblages of mammals and birds”
Microevolution
descent with modification, change in the frequency of heritable traits in a population
Speciation
origin of a new species
Macroevolution
evolution above the species level, long-term patterns of speciation and extinction
Mutation
change in DNA due to replication errors or damage.
the source of new genetic variation
most harmful, some help a population adapt
3 things required for natural selection
- variation in traits - phenotypic variation (appearance)
- differential reproduction (phenotype)
- there is heredity - genotype (specific alleles)
Gene flow
movement of alleles between populations by migrations of individuals
Genetic drift
random fluctuations in allele frequency
Founder effect
small number of individuals establish a new population
loss of genetic diversity and and a high frequency of specific alleles
4 causes of evolution
- selection
- mutation
- gene flow
- genetic drift
Biological Species Concept
groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups
Evolutionary Species Concept
a phyletic lineage (ancestral-descendent sequence of interbreeding populations) evolving independently of others
Allopatric speciation
new species formed from geographically isolated populations
Peripatric speciation
new species formed from a small population isolated at the edge of a larger population
Parapatric speciation
new species formed from a continuously distributed population
Sympatric speciation
new species formed from within the range of the ancestral population*
Phylogeny
the evolutionary history and relationships of organisms, a hypothesis
Phylogenetic tree
a branching diagram showing the phylogeny (relationship) of a group of organisms
What do the branching points on a phylogenetic tree represent?
the common ancestor
What is the order of organization in Linnean taxonomy?
Domain –> Kingdom –> Phylum –> Class –> Order –> Family –> Genus –> Species
What are sister taxa?
taxa that share a unique common ancestor not shared with any other taxa
Monophyletic group
also known as a clade
the common ancestor and all its descendants
Vicariance
(allopatric speciation) a geographic barrier forms within the geographic range of a species
ex. a mountain range forming between 2 populations
Dispersal
members of a species moving from their origin population across a geographic barrier to a new area
ex. birds flying to an island and starting a new population or seed dispersal like dandelion
