Speciation Flashcards
clade
group of organisms that consists of an ancestor and all its descendents
taxon
named taxonomic group
where would the most recent common ancestor be
most recent shared node
what are used to construct phylogenetic trees
only homologous traits
speciation
the engine of biodiversity
species
a group of organisms that share certain traits
morphological species concept
members of species look alike and share physical traits
lineage species concept also known as
phylogenetic species concept
lineage species concept
species as branches on the tree of life
ecological species concept
species in which a species is a set of organisms adapted to a particular set of resources, called a niche, in the environment
biological species concept
groups of actually or potentially interbreediing populations which are reproductively isolated from other such groups
there is no single definition of species that can apply
to all organisms
sexual dimorphism
females and males of the same species look different from one another
when is morphological species concept used
when there is nothing else to resort to, lack of behavioral or reproductive behaviors observations
fossils
what species can lineage species concept describe
organisms without sexual reproduction
bacteria
in a ecological species concept, every species would
occupy a specific niche
concept used on interbreeding populations
biological species concept
in biological species concept, evolutionary forces
operate independently on taxa and they have become different species
speciation
one species splits intot two
speciation in biological species concept
the evolution of reproductive isolation within a population whose members formerly exchanged genes
allopatric speciation
involves geographic barriers
sympatric speciation
without geographic barriers
dominantt mode of speciation in most groups of sexually producing organism
allopatric
sympatric speciation description
subpopulations somehow form in the same area and diverge such that gene flow between them ceases, even though interbreeding is not prevented by geography
sympatric speciation example fish
certain wavelengths of color r processed better for certain fish at certain depths and they separate because of that even though there is no physical barrier
barriers that prevent interbreeding before fertilization
prezygotic isolating barriers
habitat isolation
eg terrestrial and aquatic species of garter snake
temporal isolation
mating periods don’t overlap
behavioral isolation
individuals reject or fail to recognize potential mating partner based on courtship rituals or mating signals
mechanical isolation
differences in size, shape, position of reproductive organs make mating impossible
gametic isolation
sperm and egg fail to fuse
sea urchins
postzygotic isolating barrier
after fertilization
hybrid inviability
zygotes or adults have low survival rates or fail to develop/survive
tigress and leopard
hybrid infertility
mules, ligers
hybrid breakdown
F1 hybrids are okay but later generations become inviable/infertile: rice cultivars
