Biology - Evolution 2: The Origin of Species, Macroevolution, and Human Evolution

Speciation

When one species splits into 2 or more species

biological species concept

Defines a species as a group of populations that can interbreed and produce fertile offspring

Morphological Species Concept

Groups of populations that have similar anatomy

Hybrid

The baby of 2 interbred species

Ecological Species Concept

Defining species in terms of niches.

Phylogenetic Species concept

A definition of species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life.

Does not help with things like hybrids or fossils

What is a problem with the Biological Species Concept

An example is what about birds and bats, since they both have wings, are they the same species?

What's wrong with the morphological species concept?

Not specific enough

What's wrong with the ecological species concept?

Where do you draw the line?

What's wrong with the Phylogenetic Species Concept

Postzygotic Barriers

Barriers that prevent the hybrid zygote from becoming a fertile adult.

Prezygotic Barriers

Barriers that impede mating or hinder fertilization.

Habitat Isolation

populations live in different habitats and do not meet

Temporal Isolation

When two species breed at different times of day, season, or years.

Behavioral Isolation

Isolation caused by differences in courtship or mating behaviors

Mechanical Isolation

Mating is unsuccessful due to differences in reproductive organs

Gametic Isolation

Molecular Incompatibility between sperm and eggs

Reduced Hybrid Viability

Genes of the different parent species may interact and impair the hybrid's development

Reduced Hybrid Fertility

Hybrids are not fertile after birth, even if development is stable

Hybrid Breakdown

Hybrid is fertile, but when they breed the next generation is not fertile

Reproductive Barrier

a biological feature of a species that prevents it from interbreeding with other species even when populations of the two species live together

Allopatric Speciation

the process of speciation that occurs with geographic isolation

Sympatric Speciation

The formation of new species in populations that live in the same geographic area

Adaptive Radiation

An evolutionary pattern in which many species evolve from a single ancestral species

Hybrid Zones

regions in which members of different species meet and mate, producing at least some hybrid offspring

Reinforcement Hybrid Zones

strengthening of reproductive barriers; hybrids gradually cease to be formed

Fusion Hybrid Zones

reproductive barriers weaken until the two species become one, hybrid species is stronger than parental species

Stability Hybrid Zones

Both hybrids and parental species are equally fit, Fit hybrids continue to be produced

Punctuated pattern

Periods of little change followed by rapid evolution, and a long stasis

Gradual evolution over time

Gradualism

Plate tectonics

A theory stating that the earth's surface is broken into plates that move.

Biogeography

Study of past and present distribution of organisms

Pangea

A supercontinent containing all of Earth's land that existed about 225 million years ago.

Taxonomy

The scientific study of how living things are classified

Binomial format

genus and species

Phylogeny

Evolutionary history of a species

Systemics

A scientific study focused on classifying organisms and determining their evolutionary relationships.

Phylogenetic Trees

A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms.

Molecular Systemics

Uses DNA and other molecular data to determine evolutionary relationships

Exaptation

Evolutionary adaptation of an existing structure for a completely new purpose

Eukarya

Eukaryotic organisms that can be unicellular or multicellular; they may or may not have a cell wall

Bacteria

Prokaryotic, unicellular organisms that contain a plasma membrane and cell wall and live in regular environments

Archaea

Prokaryotic, unicellular organisms that contain a plasma membrane and live in extreme environments

Three-domain system

A system of taxonomic classification based on three basic groups: Bacteria, Archaea, and Eukarya

Phylogenetic Trees

Branching diagrams that depict hypotheses about evolutionary relationships.

Cladistics

Grouping of organism by common ancestry

The Ancestral species and all of its evolutionary descendants

Clade

Shared Derived Character

Evolutionary novelty unique to that clade.

Shared Ancestral Character

A character, shared by members of a particular clade, that originated in an ancestor that is not a member of that clade.

Outgroup

A species of lineage this is closely related to but not part of the group we are studying

Ingroup

Species who we are studying