Chapter 24 Flashcards
why is it important to identify species
- endangered species
- medicine (malaria, etc.)
- biodiversity conservation effects
how do we distinguish species?
- morphological traits
- the ability to interbreed
- molecular features
- ecological factors
- evolutionary relationships
microevolution
evolution on the small scale in allele freq. in a population
macroevolution
- evolutionary changes that produce new species + groups of species
- predicted to take thousands to millons of years
speciation
an ancestral species gives rise to one or more dependent species
(the point at which micro turns into macroevolution
species concept
a way of defining a concept of a species, and providing an approach to differentiate 20 different concepts
subspecies
2 or more geographically restricted groups of the same species display 1 or more traits that are different
However, not enough difference to be different species
biological species concept
used to distinguish species, a species is a group of individuals whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring but cannot successfully interbreed with members of other species.
cryptic species
species whose differences are not physical; could be genetic, behavorial, or physiological
evolutionary lineage concept
used to distinguish species; states that a species is derived from a single distinct lineage and has its own evolutionary tendencies and historical fate.
uses DNA
ecological species concept
used to distinguish species; considers a species within its native environment and states that each species occupies its own ecological niche.
general lineage concept
aka phlogentic concept
A widely accepted approach used to distinguish species; states that each species is a population of an independently evolving lineage.
allopatric speciation
a form of speciation that occurs when a population becomes geographically isolated from other populations and evolves into one or more new species.
sympatric speciation
a form of speciation that occurs when members of a species that initially occupy the same habitat within the same range diverge into two or more different species even though there are no physical barriers to interbreeding.
habitat isolation
species occupy different habitats, so they never come into contact with each other
temporal isolation
species have different mating or flowering seasons or times of day or become sexually mature at different times of the year.
behavioral isolation
sexual attraction between males and females of different animal species is limited due to differences in behavior or physiology
mechanical isolation
morphological features such as size and incompatible genitalia prevent 2 members of different species from interbreeding
gametic isolation
gametic transfer takes place, but the gametes fail to unite with each other. This can occur because the male to female gametes fail to attract
hybrid inviability
the egg of one species is fertilized by the sperm from another species, but the fertilized egg fails to develop past the early stages
hybrid sterility
an interspecies hybrid survives, but it is now sterile
hybrid breakdown
the F1 species is viable and fertile but F2 and so on become inviable over time
secondary contact
formerly diverged population/species come back into contact with one another.
a.) hybridization returns all individuals to 1 population or species
b.) hybridization to create a new species in the hybrid zone
c.) reinforcement of the previous separation
polyploidy
the condition in which a cell/organism has 3 or more sets of chromosomes
this is a gentic change that can cause immediate reproductive isolation
