Studied by 6 peopleBiological Species Concept
Defines species as a population that can produce fertile and viable offspring in nature.
Pre-Zygotic Barriers
Reproductive barriers that occur before syngamy.
Temporal Isolation
Breeding cycles don’t match, leading to reproductive isolation.
Mechanical Isolation
Breeding is attempted but unsuccessful due to physical incompatibility.
Gametic Isolation
Fusion between gametes doesn’t occur, causing the termination of the non-organism.
Behavioral Isolation
Nonrandom mating due to differences in behavior.
Post-Zygotic Barriers
Reproductive barriers that occur after syngamy.
Reduced Hybrid Viability
No viable and fertile offspring are produced.
Reduced Hybrid Fertility
Offspring is produced but is sterile.
Hybrid Breakdown
First generation produces fertile and viable offspring, but subsequent generations are weak and unable to reproduce.
Allopatric Population
A population that is separated by a barrier and exposed to different environments.
Allopatric Speciation
Reproductive isolation occurs between the two populations due to differences in gene pools and extreme clines.
Sympatric Population
Two different species that coexist in the same environment.
Sympatric Speciation
One population splits into two based on behavioral isolation.
Cladograms
Graphs or charts that show inferred common ancestry and related characteristics.
Gradualism model
A model of evolution where change occurs slowly over time.
Punctuated Equilibrium Model
A model of evolution where there are sudden, rapid changes leading to the formation of two populations.
Evolutionary Development
Interdisciplinary science between evolutionary biology and the study of development.
Gene regulation
Control of gene expression in development.
Phylogeny and Systematics
The study of evolutionary relationships and classification of organisms.
Fossil Formations
The process of fossilization.
Radioactive Dating
Measuring the amount of half-lives that have passed to determine the age of a sample.
Geological Timescale
Divided into three eras - Precambrian, Paleozoic, and Cenozoic.
Allopolyploid
Organism with a different diploid number than both parents, resulting from two species.
Autopolyploid
Difference in chromosome number in offspring of the same species, resulting in a tetraploid.
Mass extinctions
Periods of time with a significant loss of biodiversity.
Iridium
Radioactive element found in a layer separating dinosaur and non-dinosaur fossils.
Phylogenetic Tree
Diagram showing inferred common ancestry and evolutionary relationships.
Law of Parsimony
The simplest explanation is typically correct.
Monophyletic
Explains common ancestry for one clade.
Shared primitive
Homology feature predating a taxon in all species.
Shared derived
Something new and unique to a clade or species.
Outgroup comparison
Comparison to an external group to determine evolutionary relationships.
Adaptive Radiation
Changes that occur when moving away from a common ancestor.
convergent evolution
the process by which two unrelated and dissimilar species come to have similar traits, often because they have been exposed to similar selective pressures.
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