Final Definitions Flashcards
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
Inclusive fitness
Older females may benefit from helping rear young in their families that aren’t their young b/c they share genes
Genomic imprinting
Genes inherited from either parent silenced due to methylation, can result in offspring who express either maternal or paternal copies of the gene but not both
Morphological/Linnean species concept
Applicable to all sexual asexual & fossil organisms, out of favour b/c DNA sequencing & phylogenetic analysis
Biological species concept
Species are groups of actually/potentially interbreeding populations that are reproductively isolated from other such groups, widely accepted for sexually reproducing organisms
Phylogenetic species concept
Smallest possible group descending from a common ancestor & recognizable by unique derived traits
Lineage species copncept
Species are metapopulations of organisms that exchange alleles frequently enough that they comprise the same gene pool & therefore the same evolutionary lineage
Allopolyploid
A species with multiple sets of chromosomes derived from two different species
Behavioural ecology
Study of connections b/t ecology, evolution, & behaviour
Behaviour
Response to a stimulus mediated by the nervous system
Hominin
~30 fossil non-ape “pre-humans” & modern humans, living humans & all distinct non-ape relatives
Allopatric speciation
The evolution of a new species due to geographic barriers physically dividing a population into two and preventing gene flow between them long enough for them to become separate species
Proto-oncogenes
Genes that have the potential to cause cancer when they acquire certain mutations
Oncogenes
Mutant versions of proto-oncogenes
Competitive exclusion principle
2 closely related species in the same environment leads to one getting outcompeted
Tinkerer
Someone who makes small changes in something that already exists
Life history
The pattern of investment an organism makes in growth & reproduction; includes organism’s age at first reproduction, number & size of offspring produced, & life span
Species life spans
Genetic makeup controls age of reproductive maturity, numbers & sizes of offspring, & sex ratios
Reproductive barriers
Intrinsic biological features of organisms that reduce likelihood of interbreeding & producing viable offspring
Adaptive radiation
Rapid diversification into a range of uncontested niches due to a lack of competition
Reciprocal selection
Selection that occurs in 2 species due to their interactions w/ each other, example- red queen effect
Cospeciation
When a population speciates in response to & in concert with another species
Individual selection
Selection arising from variation in fitness among individuals
Group selection
Differential fitness of groups causes some groups to outcompete others & ultimately have higher fitness, slower to evolve b/c individuals in groups also favour their individual fitness
Kin selection
Selection arising from indirect genetic benefits of helping relatives raise offspring rather than reproducing yourself
Eusociality
Most members never reproduce themselves but help rear offspring of a few dominant members, seen in hymenoptera (ants, bees…), termites, naked mole rats
Haplodiploidy
Diploid offspring formed from fertilized eggs are female & haploid offspring formed from unfertilized eggs are male
Paleoanthropology
Study of human origins
Prosimians
Oldest primate clade
Pierolapithicus
Late Miocene fossil ape
Biological evolution
Any change in the inherited traits of a population that occurs from one generation to the next
