ch 11 Species and Speciation

These flashcards cover key concepts related to species definitions and the process of speciation, including barriers to reproduction, various modes of speciation, and definitions of species concepts.

Species Definition

A group of organisms that can interbreed and produce fertile offspring, sharing a common evolutionary history.

Speciation

The process by which populations attain reproductive isolation

Reproductive isolation

Biological barriers that impede members of different species from interbreeding and producing viable, fertile offspring

Prezygotic Barriers

Prevent mating or fertilization if mating does occur

Postzygotic Barriers

Prevent hybrid offspring if 2 species from developing into viable, fertile adult

Parapatric Speciation

Geographically continuous population over extremely vast distances(para=through, patra = homeland) experiences divergence

Sympatric Speciation

Speciation that occurs in populations that live in the same geographic area and diverge due to ecological factors.

Morphological Species Concept

Morphological species concept: organisms of the same species share more similar characteristics with each other than those of different species because of a longer shared evolutionary history

Genetic Species Concept

Organism of the same species share more similar DNA than those of different species because of a longer shared evolutionary history

Biological Species Concept

species are groups of organisms that can interbreed and produce fertile offspring and are reproductively isolated from other species

Adaptive Radiation

Periods of rapid evolutionary change where organisms diversify into many species adapted to different niches.

Ring Species

continuous populations over large geographic areas form a ring that can interbreed except where the populations rejoin

Competitive Exclusion

The principle that two species competing for the same resource cannot coexist if other ecological factors remain constant.

Niche

The specific biotic and abiotic resources utilized by a species.

Vicariance

Population split by the formation of geographic barrier

Dispersal

Durand as a result of movement to new areas results in reproductive isolating as population no longer continues

Temporal Isolation

species breed at different times of day, season, or year

Behavioral Isolation

Reproductive isolation due to differences in mating behaviors.

Mechanical Isolation

Reproductive isolation due to incompatibility of reproductive organs.

Reduced viability

Hybrid either fail to develop or are very frail and unlikely to survive

Hybrid sterility

Hybrids may sterile or have lower fertility

Allopatric speciation

Reproduction prevented by geographic isolation of a previously continuous population

Sympathetic speciation

Speciation occurs in populations that live in the same geographic area

Punctual equilibrium

Rapid bursts of speciation followed by relatively little change

Gradual model

Species diverge steadily over time

Adaptive Radiation

Period of evolutionary change in which organisms form may new species with adaptations specialized to different niches

Competitive exclusion

2 spices will never be perfectly equally successful at utilizing a resource so more successful competitor will exclude the other from its niche

Resource partitioning

Similar species can coexist in an area if they use different sets of similar resources or the same resource at different times