Ch.24 Speciation Flashcards
What is the three criteria for identifying species
- The biological species concept
- The morphological species concept (morphospecies)
- The phylogenetic species concept
What are the criteria/concepts to identify whether populations represent distinct species
Biological species concept
Morphospecies concept
Phylogenetic species concept
Define biological species concept
population or group of populations that are reproductively isolated from other groups
members of a species have the potential to interbreed in nature to produce viable offspring but cannot interbreed successfully with members of other species
Define morphospecies concept
The definition of the species as a population or a group of populations that have measurably different anatomical features from other groups
Define phylogenetic species concept
The definition of a species as the smallest monophyletic group in a phylogenetic tree
Define speciation
Occurs when a group within a species separates from other members of the species and develop its own unique characteristics
Define allopatric speciation
When a species separate into two separate groups which are isolated from one another
They do not have overlapping geographic ranges
When does geographic isolation occur?
1 it occurs either by dispersal
- Or vicariance
When can sympatric speciation occur?
When speciation among populations within same geological area
If Gene flow occurs what can happen to diverged populations?
May fuse into a single species
Define hybridization
It is when parents from different species, populations or strains come together and mate
Secondary contact can lead to
Reinforcement
Gene flow between different species can lead to the formation of
Hybrid zones
What happens when speciation by hybridization occurs?
A new branch is added to the tree of life by the merging of parts of preexisting branches
Define autopolyploid
It is the state of having more than 2 sets of chromosomes due to a mutation that doubled the chromosome number from both the same species mating
Define hybrid zone
Is a geographic area where interbreeding between two populations occur and hybrid offspring are common
Define genome
All the hereditary material (DNA or RNA) in a virus, cell or organism
Define polyploidy
It is a type of mutation that occurs when there is an error in meiosis or mitosis that results in More than two sets of chromosomes
Define niche
The range of ecological resources that a species can use and the range of conditions it can tolerate
Define sympatry
Is a condition in which two or more populations live in the same geographic area or close enough to permit interbreeding
Define sympatric speciation
It is the separation of populations living within the same geographic area into different species as the result of their genetic isolation
Define allopatry
conditions in which two or more populations live in different geographic areas
Allopatric speciation starts in what two ways?
- dispersal- the movement of individuals from done place to another
2.vicariance- the physical splitting of a habitat
Define taxonomy
It is the branch of science concerned with classification especially of organisms
Define Synamorphy
“Unique forms” where Homologous traits are found in common ancestors and descendants but missing in more distant ancestors
Define species
A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding
Define genetic isolation
It is the lack of mixing between organisms of the same species
Prezygotic isolation
It is when individuals from different species are prevented from mating
it is apart of biological species concept
PostZygotic isolation
It is when the hybrid Offspring do not survive or produce
It is apart of the biological species concept
What is the word for the physical splitting of a habitat
Vicariance 
It Is the term for the physical splitting of the population into a smaller more isolated populations by a geographic barrier
Vicariance
This is when a population moves to a new habitat colonizers it and found a new population
Dispersal
This is the state of having more than two full sets of chromosomes due to the HYBRIDIZATION between 2 different species
Allopolyploid
Polyploid
It is the state of having more than two full sets of chromosomes either from the same species or from different species
