Ch 14 & 15 Flashcards
Define Speciation
process where one species splits into 2 or more species
Species come from latin word meaning…
kind or appearance
Define Biological Species Concept
species as a group of pop whose members have potential to interbreed & produce fertile offspring
Define Reproductive Isolation
barriers that stop members of 2 species from producing viable, fertile offspring.
Examples of Hybrids
Liger, Mule, & growler
Define Ecological Species Concept
identifies species by ecological niches. Focuses on unique adaptations to specific roles in a biological community.
What’s a niche? (species concept)
specific area it roams, role/function or interrelationship w/ biotic/abiotic factors
Define Morphological Species Concept
classifies organisms mainly on physical traits (shape, size, & other feats of form)
Define Phylogenetic Species Concept
species - smallest group of individuals that
share a common ancestor and form one branch on the tree of life
Info on Phylogentic Species Concept?
Trace phylogeny by comparing morphology, DNA or biochemical pathways / biggest drawback is agreeing on the amount of difference for species.
Info on Reproductive Barriers.
Keep species separate / Reproductive isolation depends on 1 or more types of reproductive barriers
Prezygotic Barriers
Habitat / Temporal / Behavioral / Mechanical / Gametic - Isolations
Habitat Isolation + example?
Lack of opportunities to see each other / One species lives in trees, the other on the ground
Temporal Isolation + example?
Breeding at diff times or seasons / Frogs live n same pond - breed diff seasons
Behavioral Isolation + example?
Failure to send/receive appropriate signals / Certain group of birds only respond to certain mating calls
Mechanical Isolation + example?
Physical incompatibility of reproductive parts / Great Dane can’t mate w/ a chihuahua
Gametic Isolation + example?
Molecular incompatibility of eggs/sperm/pollen or stigma
Postzygotic Barriers?
Reduced hybrid viability or fertility / Hybrid breakdown
Reduced hybrid viability + example?
Hybrids r produced but fail to reach sexual maturity / Diff frog species mate but offspring won’t live past tadpole stage
Reduced hybrid fertility + example?
Hybrids mature but are sterile / Mules
Hybrid breakdown + example?
Hybrids are viable & fertile but their offspring are feeble or sterile / Hybrid copepods
.
Info on Allopatric speciation
interruption of gene flow between pop
of same species where the pop is divided into geographically isolated subpops. / most common cause of speciation
Info on Sympatric Speciation.
new species arises in same area as parent species / Polyploidy, habitat diff & sexual selection can reduce gene flow in these pops. /
○ Sexual selection can create speciation
when mate choice is dependent on
physical characteristics
Info on Polyloid.
cells have more than 2 complete sets of chromosomes / cause - errors in cell division.
Define adaptive radiation.
evolution of many diverse species from a common ancestor
Define Hybrid zones.
where diff species meet & mate / may produce hybrid offspring.
What’s fusion? (Hybrid zones)
reproductive barriers r weak until 2 species fuse into 1.
What’s reinforcement? (Hybrid zones)
hybrid offspring less fit both parent species. Natural S will reinforce reproductive barriers
What’s stability?
(Hybrid zones)
Fit hybrids continue to reproduce
Define Punctuated equilibria
long periods w/ little physical change interrupted by the brief periods of sudden change
Info on “Spontaneous Life?”
people believed that nonliving could create living organisms - French scientist, Louis Pasteur, disproved this
What was Louis Pasteur experiment? (+ date)
1862 / A experiment using nutrient broth that tested whether microbes spontaneously generated from the broth
or not.
Info on Protocells
In a cell, enzymes build polymers out of monomers / form when lipids are mixed with water, creating vesicles - faster w/ clay
Info on “Self-Replicating RNA”
Early genes were likely short RNA molecules that formed spontaneously, self-replicated via ribozymes, and were absorbed by protocells, eventually leading to DNA-based life.
Info on “Early Life”
Life began w/ prokaryotic stromatolites / Single-celled eukaryotes then multicellular eukaryotes appeared / Finally photosynthetic prokaryotes colonized land.
Define Radiometric Dating
method of determining ages of rocks
based on decay of radioactive isotopes.
Info on “Continental Drift”
Earth’s plates cause continental drift / 250 mya Pangaea forms / later splits into Laurasia & Gondwana / Modern continents began forming 66 mya
Info on Drift Distribution
Continental drift shapes animal world by spreading related organisms worldwide / evo patterns thru past mergers and separations of landmasses
Info on “Mass Exticntions”
Permian Extinction (252 mya) - 96% of marine & 70% of terrestrial life by volcanic eruptions / Cretaceous Extinction (66 mya) - most dinosaurs, except birds
Info on “Human Impact on Extinction”
Human activity driving 6th mass extinction, accelerating species loss 100–1,000 times / ME disrupt ecosystems, causing collapses
Info on “Diversity and Development”
Adaptive radiations boost biodiversity / Evo-devo research show small genetic changes n development can lead to major evo shifts, shaping life’s diversity over time.
Define Paedomorphosis
retention in the adult body of structures that were juvenile features in ancestral species
Define Homeotic genes
Homeotic genes that control body structure development
Info on “Novel Traits Arise”
New features evolve gradually, form complex structures like eyes / Feathers n Dinos developed in stages, eventually bird flight
Define Taxonomy
branch of biology on identifying, naming & classifying species
Info on “Taxonomy & Phylogeny”
Linnaean system classifies species w/ 2 parts: genus & species / Grouped into families, orders, classes, phyla, kingdoms, & domains.
Define Phylogeny
evolutionary history of species/group of species
Define Systematics
discipline of biology that focuses on
classifying organisms & determining their evolutionary relationships / includes taxonomy
Info on “Convergent Evolution”
CE - unrelated organisms develop similar traits cuz of similar environments. This similarity (analogy) can create confusion in phylogenetic classification.
Info on “Divergent Evolution”
DE - when species from common ancestor become distinct due to diff selection pressures / leads to speciation over time.
Info on “Cladistics”
groups organisms by common ancestry / clade includes an ancestor and all its descendants - forms monophyletic group
