Ch. 24 & 26 Flashcards
(48 cards)
Define anagenesis
Anagenesis is the transformation of one species into another
Define cladogenesis
When a gene pool splits and is exposed to different selection pressures which creates one or more new species
What are differences between cladogenesis and anagenesis
Anagenesis: new specie is born out of TRANSFORMATION , does not branch
Cladogenesis: new specie is born out of CREATION (from selection pressures) , does branch out
What is the Biological Species Concept
Organisms are reproductively compatible with members of their own species and can reproduce with each other, but they CANNOT INTERBREED with other populations
Who is Ernst Mayr?
Scientist who created the biological species concept
Define biological species
Must be fertile and able to interbreed
List the 5 prezygotic barriers
Habitat, temporal, behavioral, mechanical, and gametic isolation
List the 3 postzygotic barriers
Reduced hybrid viability (inviability), reduced hybrid fertility, and hybrid breakdown
What is meant when barriers are postzygotic or prezygotic
Postzygotic barriers are barriers that are meant to stop inter-species breeding AFTER zygote has been fertilized
Prezygotic barriers are barriers that are meant to stop inter-species BEFORE the zygote can be fertilized
Explain hybrid breakdown**
In hybrid breakdown, the first generation of inter-species breeding may be fertile but the next generations will be feeble or sterile
What are the limits of the biological concept
The concept does NOT apply to: asexual organisms, fossils, organisms that have little information known about their reproduction
Define the ecological species concept
This concept defines species by their ecological niche (aka, how they adapted to a particular set of resources in an environment)
Define paleontological species concept
Concept used to define species known only from the fossil record (morphologically discrete)
Define the phylogenetic species concept
Concept used to define species as a set of organisms with unique genetic history
Define the morphological species concept
Concept that defines a species by their structural features
What is allopatric speciation
Where a new species is developed as a result of being geographically isolated from the parent population
Define sympatric speciation
Where a new species is formed from the same ancestral population without any geographical separation
List and describe some mechanisms that may lead to a divergence of isolated gene pools
For gene pool isolation to occur, a species must be divided and adapted to their new/differing surroundings. This can be done through:
- allopatric speciation (geographic isolation)
- sympatric speciation (reproductive barrier isolation)
- adaptive radiation (species of common ancestor rapidly diversifies when exposed to many new environments)
Define phylogeny
The evolutionary history of a species or group of related species
Define systematics
Understanding the diversity and relationships of organisms (present-day and extinct) and evolutionary relationships.
Uses morphological, biochemical, and molecular comparisons.
Distinguish between systematics and phylogeny
Phylogeny: the actual history of the species
Systematics: the understanding of the relationships and diversity the specie has
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What are homoplasies
Independently evolved molecular sequences or analogous structures
What is taxonomy
The ordered division of organisms into categories based on characteristics - used to assess similarities and differences
What is binomial nomenclature
The two-part scientific name of a species, consists of the genus + the specific ephitet. Both parts must be said to refer to the specific organism.
