Bio exam 3 chp 16 evolution Large scale

Speciation

Splitting of one species into two or more new species

Macroevolution

Changes in a population over a very long period of time

Defining Species

Have a shared gene pool; Interbreed; reproductively isolated; not based on appearance;

Reproductively isolated

Each species is ___ __ from every other species.

Gene flow occurs

between populations of a species but NOT between different species

mating calls

birds have different ____ ___, that separate each other from reproducing

Reproductive Barriers

Prezygotic and Postzygotic barriers

Prezygotic barriers

prevent fertilization or the formation of a zygote; Temporal, Ecological, Behavioral, Mechanical, Gametic isolation

Postzygotic barriers

prevent zygotes from developing into healthy and fertile offspring (mule=infertile), Zygote mortality, Hybrid sterility, F2 fitness

Gametes

sperm and egg

Zygote

sperm + egg =

Temporal Isolation

The two species breed at different times. -mating is prevented (prezygotic barrier)

Ecological Isolation

The two species breed in different portions of their habitat. -mating is prevented (prezygotic barrier)

Behavioral Isolation

The two species respond poorly to each other’s courtship displays or other mating behavior (mating calls) -mating is prevented (prezygotic barrier)

Mechanical Isolation

The two species are physically unable to mate. -mating is prevented (prezygotic barrier)

Gametic isolation

The gametes of the two species cannot fuse, or they survive poorly in the reproductive tract of other species. -fertilization is prevented (prezygotic barrier)

Zygote mortality

Zygote fail to develop properly, and they die before birth. - no offspring are produced (postzygotic barrier)

Hybrid sterility

Hybrids survive poorly or reproduce poorly. -hybrids are not successful (postzygotic barrier)

F2 fitness

Hybrid is fertile, but F2 hybrid had reduced fitness. - offspring cannot reproduce (postzygotic barrier)

Models of Speciation

Allopatric, Sympatric

Models of Speciation: Allopatric

Speciation based on geographic isolation

Models of Speciation: Sympatric

Same Place; Population develops into two or more reproductively isolated groups without prior geographic isolation. Found among plants due to polyploidy, Formation of bread wheat.

Adaptive Radiation

New species evolve from a single ancestral species

Fossils

Traces and remains of past life or any other direct evidence of past life. (holds record of past)

Paleontology

Science of discovering and studying the fossil record, and making decisions about the history of species.

Paces of Speciation

Gradualistic model, Punctuated equilibrium

Paces of Speciation; Gradualistic model

Darwin though evolutionary changes occurred gradually (overtime) (SLOWWWWWWW)

Paces of Speciation; Punctuated equilibrium

Period of equilibrium (no change) is punctuated (interrupted) by speciation.

Mass Extinction of Species

Disappearance of large number of species or a higher taxonomic group within a relatively short period of time. (continental drift) (impact of meteorites)

how many mass extinctions occurred

5

Pangaea

continental drift

Systematics

Study of evolutionary history of life on Earth; One goal= determine phylogeny

Phylogeny

Evolutionary history of a group of organisms

Taxonomy

Identifying, naming and classifying organisms

Linnaean Classification

Binomial system and Naming rules

Linnaean Classification: Binomial System

Genus and specific epithet

Linnaean Classification: Naming rules

Genus capitalized, Italicized (species), Genus can be abbreviated

epithet

a descriptive word or phrase or used in place of the name to highlight a key quality, characteristic, or title

Phylogenetic Trees

Diagram that indicates common ancestors and lines of descent (Inclusivity)