Lecture 3 Study Guide Flashcards
Hierarchy of taxonomic categories
In order of most to least inclusive, Domain, kingdom, phylum, class, order, family, genus, speices
Taxonomy
The naming and classification of organisms
Speciation
The origin of two species from a common ancestral species, a branching point in an evolutionary tree
Typological or essentialist species concept
An individual was a member of a species if it conformed to that type or ideal in fixed morphological properties
Morphological species concept
species are groups of individuals that are morphologically similar to one another and are morphologically distinct from other such groups
Phylogenetic Species Concept
An irreducible cluster of organisms diagnosably different from other such clusters, and within which there is a parental pattern of ancestry and decent
Biological species concept
species are groups of actually or potentially interbreeding populations which are reproductively isolated from other such groups
Reproductive Isolation
biological differences between the populations reduce gene flow between them, even if they are not geographically separated
isolating mechanisms or barriers to gene flow
gene flow between biological species is partially or entirely prevented by biological differences
prezygotic isolating barriers
barriers that reduce the likelihood of the transfer of gametes to members of other species
postzygotic isolating barriers
Barriers that reduce survival or reproductive rates of hybrid zygotes
geographic isolation
species occur in different areas which are often separated bt a physical barrier
Ecological isolation
breeding at different times of the year (seasonal isolation) or different microhabitats
Behavioral isolation
results from mate recognition systems that consist of signals and responses such that one sex will not respond to the other unless it receives the appropriate signals
Postmating prezygotic barriers
results when females terminate mating if the male’s genitalia fail to provide the appropriate stimulus, may also occur after transfer of sperm but fertilization fails to occur
Gametic Isolation
Occurs when gametes of different species fail to unite
Hybrid inviability
hybrids have lower survival rates that non hybrids
hybrid vigor/heterosis
when hybrids have higher survival, this is not common but when it happens it’s often in interme=ediate or disturbed habitats
hybrid sterility
differences between genes from two parents may result in disharmonious genetic interactions, resulting in hybrids not being able to produce viable gametes
Allopatry
species or distinct populations with geographic ranges that are separate from one another
Sympatry
species or distinct populations with overlapping geographic ranges
Parapatry
species or distinct populations with adjacent but non overlapping geographic ranges
hybrid zone
a region where genetically distinct parapatric forms interbeed
secondary contact
when range shifts cause geographically separated (allopatric) populations to come into contact, may result in hybrid zone
intergrade zone
when genetically distinct populations merge gradually from one to another
primary contact
occurs when genetically distinct populations merge gradually from one to the other, but were never allopatric, may result in an integrated zone
cline
gradual change in character trait or allele frequencies over geographic distances
Bergmanns rule
the principle that in warm blooded animal species having distinct geographic populations, the body size of animals living in cold climates tend to be larger then the animals of same species in warm climates. Larger bodys produce more body heat. they also have smaller surface areas relative to there mass, resulting in relative lower rate of heat radiation
Ecotype
a phenotype that is associated with a particular habitat
