IB Biology Topic 10: Macroevolution and Speciation

Directional selection

Directional selection

________ has the phenotypic distributed to two extreme phenotypes, ‘ two- hump graph.

Disruptive selection

________ has phenotypic distribution entirely towards one phenotypic extreme.

Fossil records

________ show abrupt changes in a species with periods of ‘ extinction that are perceived to be periods of stasis under the theory of punctuated evolution.

rapid bursts

Punctuated equilibrium= when speciation occurs in short, ________ with periods of no change in between.

Low genetic variation

________ /diversity implies that if one organism of such a population is vulnerable to a disease, the entire population is also vulnerable.

Gene

________ pool= the combination of all alleles of a trait for a species.

meiosis

Occurs when ________ does not occur correctly and the chromosomes are unable to be divided into two haploid gametes, and instead produce one diploid gamete by hybridization.

Behavioral isolation

________= differences in mating behaviors that for two population.

Sympatric speciation

________= occurs w /out a geographic barrier.

Temporal isolation

________= differences in mating times for two different populations.

Speciation

________ is the development of different species.

Gradualism

________= when speciation occurs gradually over time.

Species

________= a group of organisms that can mate and reproduce and produce viable and fertile offspring.