New branches form on the tree of life through the process of _____.

speciation

According to the biological species concept, a species is _____.

a group of populations whose members can interbreed in nature and produce fertile offspring

The _____ species concept is practical for identification of unfamiliar species and has been used to describe most of the 1.8 million known species on Earth.

morphological

For which one of the following groups would the biological definition of species be useful?

oaks and other sexually reproducing, extant (currently living) trees

Each biological species is genetically isolated from other species. Why do the species evolve independently?

The two species evolve independently because they do not exchange genes. Reproductive barriers keep them from successfully interbreeding

Which of the following is an example of a postzygotic reproductive barrier?

Two fruit flies of different species produce viable but sterile offspring

Which is a postzygotic reproductive barrier?

The hybrid offspring of two species of jimsonweeds always die before reproducing.

Individuals of different species living in the same area may be prevented from interbreeding by responding to different mating dances. This is called _____.

behavioral isolation

Which of the following is an example of mechanical isolation?

Many insects have intricate "lock and key" mechanisms that prevent the male genitalia of one species from engaging with the female genitalia of a different species.

Which of the following is an example of a prezygotic barrier?

Pollen is regularly exchanged between flowers of two groups of plants, but a mutual incompatibility exists so that sperm do not fertilize eggs from the "wrong" group.

A splinter population is separated from the main population of a species. Each of the populations begins to evolve independently. When has speciation occurred?

Genetic changes establish reproductive barriers between the two populations

Speciation is likely to occur between a parent population and a population that has become allopatric if _____.

the allopatric population is small and is isolated from the parent population by a formidable barrier to dispersal

Which of the following scenarios is most likely to lead to allopatric speciation?

fish living in two different spring pools separated by a large expanse of desert

Sympatric speciation typically occurs through _____ and through _____.

polyploidy in plants ... habitat differentiation in animals

Which would be a typical scenario of sympatric speciation to produce a new plant species?

Two diploid species hybridize, and for a period of time the hybrid reproduces asexually. Eventually, an error in cell division doubles the chromosome number and results in a fertile polyploid species.

A new species can arise in a single generation _____.

if a change in chromosome number creates a reproductive barrier

Scientists estimate that _____% of plant species are polyploids, mostly generated through _____.

over 75% ... hybridization between two species

What do Dodd's experiments with fruit flies indicate?

Reproductive barriers will arise most quickly if isolated populations experience and become adapted to differing environments.

What do the examples of the Japanese land snail and the monkey flower indicate?

A change in a single gene may produce effective reproductive barriers between populations in some cases.

Which statement is true of hybrid zones?

Limited interbreeding occurs between two closely related species. Over time, evolution of a strong reproductive barrier may fully separate the species; the species may continue to hybridize; or the two species may fuse into a single species.

The work of the Grants on two sympatric species of Gal�pagos finches has shown _____ to be an important source of genetic variation in both species.

hybridization

What is the major evidence for the punctuated equilibrium model of evolution?

Many fossil species appear suddenly in the fossil record, persist unchanged for long periods, and then disappear without transitional forms.

According to a recent survey of many studies, an average plant or animal lineage might produce a new species approximately once every _____.

5 million years

In order to be a species

Interbreed and produce fertile offspring

What is a mule an example of?

Hybrid fertility

What did dodds experiment show?

A prezygotic barrier forms

Peter and Mary grant took a small and large beak finch and combined them.

The hybrid could survive In wet seasons but not dry seasons

Eco

Adaptive radiation

An organism adapted over time

Microevolution

Fossil record shows

Macroevolution

Where did we used to think energy came from?

Lightning

The first organisms were

Prokaryotes that weren't photosynthetic

How did the Permian extinction happen?

Volcanoes

What do we call all of the outer layers of earth?

The crust

What were the gollopoges formed from?

Underwater volcanoes

What are homeotic genes?

Alter the placement of legs or genes

Prokaryotes have how many domains?

2

A layered rock

Stromatolite

RNA that carries out a number of enzyme-like functions

Ribozymes

The earliest evidence of life came from fossil stromatolites

Origin of prokaryotes

The oldest widely accepted fossils of eukaryotes are about 2.1 billion years old

Origin of multicellular eukaryotes

There is fossil evidence that photosynthetic prokaryotes coated damp terrestrial surfaces

Colonization of land

Based on the measurement of certain radioactive isotopes

Radiometric dating

Based on the sequence and the ages of rocks and fossils

geological record

periods of evolutionary change in which many new species form who's adaptations allow them to fill new habitats or community roles

adaptive radiation

studying how slight genetic changes can become magnified into major morphological differences

evo-devo

the retention in the adult of features that were juvenile in an ancestral species

paedomorphosis

the evolutionary history of a species or group of species

phylogeny

species from different evolutionary branches may come to resemble one another if they live in similar environments and natural selection favors similar adaptions

convergent evolution

a discipline of biology that focuses on classifying organisms and determining their evolutionary relationships

systematics

where a species belongs

genus

a two-part name

binomial

branching diagrams that reflect the hierarchical classification of groups nested within more inclusive groups

phylogenetic trees

the most widely used method in systematics

cladistics

a group of species that includes an ancestral species and all its descendants

clades

single tribe

monophyletic

shared derived characters

new traits

shared ancestral traits

traits in ancestral groups

the group of taxa that is actually being analyzed

ingroup

a species or group of species that is know to have diverged before the lineage

outgroup

a valuable approach for tracing evolutionary histories

molecular systematics

help track evolutionary time

molecular clock

the three domain system

recognizes the three basic groups: two domains of prokaryotes, bacteria and archaea, and eeukaryotes