Final Definitions Flashcards
(54 cards)
Senescence
Deterioration of an organisms biological functions as it ages
Trivets-Willard Hypothesis
Based on their condition females adjust the sex ratio of their offspring
Metapopulation
Spatially separated populations that still interact and exchange genes
Introgression
Mixing of genes & phenotypic traits in hybrids, occasional interbreeding & gene transfers
Vicariance
Formation of geographic barriers to dispersal & gene flow –> separation of once continuously distributed populations
Parapatric speciation
“at the edges”, evolution of new species w/in spatially extended pop w/ some gene flow
Introgressive hybridization
Complex repeated movement from one species into the gene pool of another species
Autopolyploidy
More than two paired chromosomes resulting from a chromosome duplication event, all chromosomes come from the same species
Allopolyploidy
More than two paired chromosomes resulting from interspecific hybridization, hybridization & chromosome duplication
True extinction
When the last member of a clade dies, can be of a species or a group of species
Extirpation
Local/partial extinction
Biogeography
The study of present & past geographical patterns of diversity
Gondwanaland
A supercontinent, includes Africa, North & South America, peninsular India, Australia, & Antarctica, formed near the beginning of Cambrian time
Punctuated equilibrium theory
States that most species undergo very little change for most of their geological history interspersed with brief periods of rapid morphological change associated with speciation
Anagenesis or gradualism
Slow & steady change in a species lineage, may also transform one species into another, may include speciation/lineage splitting
Background extinction
The normal expected rate of extinction for a particular taxonomic group. relatively slow for most organisms
Mass extinction
The loss of many whole clades in a relatively short time span, represents statistically significant excursions above background extinction rates
Virulence
Ability to cause damage or even death
Paedomorphosis
Retention of juvenile features in sexually mature adults
Geographic mosaic theory of evolution
Gene flow moves different co-evolved genes among populations (strong & weak selection) → variability in responses to selection in different populations
Batesian mimicry
A harmless or palatable mimic resembles a poisonous or distasteful model species
Mullerian mimicry
Where two or more toxic species mimic each other
Aposematic colouring
An organism with warning colours to deter predation
Aging hypothesis
DNA errors & changes in protein structure (like collagen elasticity) accumulate with age b/c telomeres shorten w/ each cell replication