BIOL 1307 MACROEVOLUTION, SYSTEMATICS, AND TAXONOMY

Macroevolution

Evolutionary changes that result in new species

Speciation

The process by which one ancestral species splits into two or more uniquw species

Each time speciation occurs, the diversity of life ___________

increases

Morphological species concept

Classification based on physical traits (shape, size, and form)

Molecular similarity concept

Species are a population that can interbreed and share morphological and genetic/molecular similarities

Analogy

Similarity between different species due to convergent evolution

_________ environmental pressures resulted in ________ features evolving separately from each other

Similar; similar

Despite being physically similar, two analogous organisms can have different…

Anatomy, physiology, and reproductive systems

How does complexity of structures help determine whether two species are exhibiting homology or analogy?

The more elements that are similar in two complex structures, the more likely they evolved from a common ancestry

When is the morphological concept limited?

When two organisms are similar physically but have different ecological roles, live in different habitats, and cannot interbreed

What is the biological species concept based on?

The potential to interbreed and produce viable, fertile offspring

________ _________ must occur in the biological species concept

Gene flow

What can play a role in the development of a new species?

Reduction/decrease of gene flow

Prezygotic barriers

Block fertilization from occuring; factors that impede members of two species from interbreeding and producing viable offspring

Postzygotic barriers

Developmental errors or post birth problems that decrease the chance of surviving long enough to reproduce

Contributors to prezygotic barriers

Habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation

Contributors to postzygotic barriers

Reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown

What are the limitations of the biological species concept?

Cannot be applied to asexual reproductive species, species are designated by an absence of gene flow, and some hybridization can occur between species that are morphologically and ecologically distinct

Allopatric speciation

A population forms a new species while geographically isolated from its parent population

Sympatric speciation

A subset of a population forms a new species WITHOUT geographic separation

Adaptive radiation

Occurs when a single ancestral species gives rise to a wide array of descendant species

When does adaptive radiation occur?

When natural pressures are released from a particular environment, species can diversify

Taxonomy

The ordered division of naming organisms

Systematics

The discipline of classifying organisms and hypothesizing evolutionary relationships

Binomial nomenclature

A latinized two name system used to classify organisms by their genus and species

Describe the binomial nomenclature system

Genus name is always capitalized and the species name is always lowercase. Entire name is italicized

List the taxonomic groups from narrow to broad

species, genus, family, order, classm phylum, kingdom, and domain

A taxonomic unit at any level of hierarchy is called a ________

taxon

Phylogenetic trees

represent hypotheses about how organisms are evolutionarily related to one another

What are the limitations of phylogenetic trees?

Cannot tell us the ages of branch points or timeline of speciation, if “higher” organisms evolved from “lesser” organisms, or which organisms are more phenotypically similar