Speciation Flashcards
Define Speciation
The process by which one species splits into 2 or more species
4 species concepts
1) Biological Species Concept
2) Morphological Species Concept
3) Ecological Species Concept
4) Phylogenetic Species Concept
Define the Biological Species Concept
Species is a group of populations that can interbreed in nature, and produce viable, fertile offspring.
Define the Morphological Species Concept
Characterizes species by body shape or other structural features
Define the Ecological Species Concept
Characterizes species by how it interacts with the environment
i. Habitat
ii. Diet
Define the Phylogenetic Species Concept
Characterizes species as the smallest group that shares a common ancestor
i. One branch on a phylogenetic tree
ii. Comparing molecular gene sequence
Define Reproductive Isolation
Barriers that prevent gene flow between groups.
Define the two types of Reproductive Isolation
1) Prezygotic Barriers: Before the zygote forms.
2) Postzygotic Barriers: After the zygote forms.
What are the 5 Prezygotic Barriers?
1) Habitat Isolation: live in different habitats
2) Temporal Isolation: breed at different times
3) Behavioral Isolation: different courtship rituals
4) Mechanical Isolation: Incompatible reproductive anatomy
5) Gametic Isolation: Gametes cannot unite
What is a hybrid?
The offspring from interspecies mating.
What are the 3 Postzygotic Barriers?
1) Hybrids Inviability: Hybrid zygote fails to develop
2) Hybrid Infertility: Hybrid is born sterile
i. Chromosomes from parents differ in #
or structure
ii. Meiosis in hybrid can’t produce
functional gametes
3) Hybrid Breakdown
i. First generation hybrids are viable/fertile
(hybrid vigor)
ii. subsequent generations are
feeble/sterile
iii. cultivated crops initially display hybrid
vigor, but then display hybrid breakdown
What are the 2 Isolations that prevent gene flow?
Allopatric speciation and Sympatric Speciation.
What is Allopatric Speciation?
“Other Homeland”
Speciation that occurs when a population is geographically separates; they live in different areas.
What is Sympatric Speciation?
“Same Homeland”
i. Habitat Differentiation: when genetic
factors enable a subpopulation to exploit
a habitat or resource not used by the
other population
ii. Sexual Selection: mate choice as a
reproductive barrier keeping gene pools
separate
Define Phylogeny
The evolutionary history of a species or group of species
What is Systematics in phylogeny?
The discipline of classifying organisms and determining evolutionary history
What is Taxonomy in phylogeny?
The discipline of classifying and naming organisms
What is Binomial Nomenclature in phylogeny?
A two-part scientific name
i. created by Carl Linnaeus in the 18th
century
ii. Uses Latin
iii. Genus (species in italics)
iv. Ex: Homo sapiens “wise man”
What is Hierarchical Classification?
The grouping of organisms into categories
Domain: Eukaryotes
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primata
Family: Hominidae
Genus: Homo
Species: Sapiens
Dear King Philip Came Over For Good Soup
Essentially Anybody Can Make Pretty Healthy Hot Soup
What is a Phylogenetic Tree?
The Branching Diagram showing evolutionary history
What are Cladistics in a phylogenetic tree?
Classifying organisms by inferring phylogeny from homologous character
i. clade: related group
ii. shared ancestral character: character
that originates from the ancestor
iii. shared derived character: novel
character that is unique to a clade
What are Branch Points in a phylogenetic tree?
Branch Points show divergence from the common ancestor
What are Sister Taxa in a phylogenetic tree?
Sister Taxa are groups that share an immediate common ancestor
What does it mean to be Monophyletic in a phylogenetic tree?
“Single tribe”; groups together the ancestor species and all of the descendants
