Biology Chapter 24 Flashcards

Questions and Answers

What is Speciation?

The process by which one species splits into two or more species (correct)

The increase in genetic diversity

An evolutionary process unrelated to species

An event that causes species extinction

What is Anagenesis?

The accumulation of changes that gradually transform a given species with different characteristics.

What is Cladogenesis?

The splitting of a gene pool into two or more separate pools, leading to the emergence of one or more new species.

What is the biological species concept?

A population or group of populations whose members have the potential to interbreed in nature and produce fertile offspring but are unable to produce offspring with those of other populations. Signup and view all the answers

What are the differences between prezygotic and postzygotic barriers to reproduction?

Prezygotic barriers impede mating or hinder fertilization, while postzygotic barriers prevent an organism from developing and/or reproducing. Signup and view all the answers

What is Habitat Isolation?

A prezygotic barrier where two species encounter each other rarely or not at all due to their location. Signup and view all the answers

What is Temporal Isolation?

A prezygotic barrier where species breed at different times of the day, seasons, or years. Signup and view all the answers

What is Behavioral Isolation?

A prezygotic barrier where unique courtship rituals and behaviors limit the chance of mating. Signup and view all the answers

What is Mechanical Isolation?

A prezygotic barrier where morphological differences prevent mating; sex organs are incompatible. Signup and view all the answers

What is Gametic Isolation?

A prezygotic barrier where the sperm of one species may not be able to fertilize the eggs of another species. Signup and view all the answers

What is Reduced Hybrid Viability?

A postzygotic barrier where genes of different parent species may interact and impair hybrid development. Signup and view all the answers

What is Reduced Hybrid Fertility?

A postzygotic barrier where hybrids may be vigorous but sterile. Signup and view all the answers

What is Hybrid Breakdown?

A postzygotic barrier where some first-generation hybrids are fertile, but their offspring are feeble or sterile. Signup and view all the answers

What is the Morphological Species Concept?

A concept that characterizes a species by its body shape, size, and other structural features. Signup and view all the answers

What is the Paleontological Species Concept?

A definition of species based on morphological differences known only from the fossil record. Signup and view all the answers

What is the Ecological Species Concept?

Defining species in terms of ecological roles (niches). Signup and view all the answers

What is the Phylogenetic Species Concept?

Defines a species as a set of organisms with unique genetic history. Signup and view all the answers

What is the basis for allopatric speciation?

When gene flow is interrupted in a population, dividing it into geographically isolated subpopulations. Signup and view all the answers

What does sympatric speciation mean?

The developing of new species in geographically overlapping populations due to genetic polymorphisms. Signup and view all the answers

What is Autoploidy?

An individual that has more than two chromosome sets, all derived from a single species. Signup and view all the answers

What is Alloploidy?

A common type of polyploidy species resulting from two different species interbreeding and combining their chromosomes. Signup and view all the answers

In what types of organisms is polyploidy speciation more common and why?

Polyploidy speciation is more common in plants because they reproduce differently and accidents in cell division occur more frequently. Signup and view all the answers

Study Notes

Speciation and Evolution Types

Speciation is the process of one species splitting into two or more distinct species.
Anagenesis (phyletic evolution) refers to gradual changes that transform a species over time, leading to new characteristics.
Cladogenesis (branching evolution) involves the splitting of a gene pool, resulting in increased biodiversity through the emergence of new species.

Biological Species Concept

Defines a species as a population that can interbreed to produce fertile offspring, while unable to do so with other populations.
Limitations include asexual organisms, fossil records, and species with unknown reproductive methods.

Reproductive Barriers

Prezygotic barriers prevent mating or fertilization, while postzygotic barriers stop developing or reproducing organisms after fertilization.
Habitat Isolation occurs when species rarely meet due to geographical locations.
Temporal Isolation happens when species breed at different times (day, season, or year).
Behavioral Isolation includes unique courtship rituals that limit mating chances between species.
Mechanical Isolation results from morphological differences that prevent successful mating.
Gametic Isolation involves sperm not being able to fertilize the eggs of a different species.
Reduced Hybrid Viability indicates that hybrid offspring may not survive due to genetic incompatibilities.
Reduced Hybrid Fertility means hybrids may be vigorous but sterile.
Hybrid Breakdown refers to first-generation hybrids being fertile, but subsequent generations being weak or sterile.

Species Concepts

Morphological Species Concept identifies species based on structural features, applicable to both asexual and sexual organisms.
Paleontological Species Concept defines species based on morphological traits found in fossils.
Ecological Species Concept focuses on the ecological roles and niches of species.
Phylogenetic Species Concept defines species by their unique genetic history.

Speciation Mechanisms

Allopatric speciation occurs when a population is divided by geographical barriers, interrupting gene flow and leading to evolutionary changes in isolation.
Sympatric speciation happens within overlapping populations, often through mutations or mating preferences, resulting in genetic polymorphisms that can create new species.
Autoploidy refers to individuals with multiple chromosome sets from a single species.
Alloploidy involves the combination of chromosome sets from two different species resulting from interbreeding.

Polyploidy and Organism Types

Polyploidy speciation is more common in plants due to their unique reproductive methods. Pollen transfer between species is frequent, leading to accidental mating.
Plants also experience more frequent accidents during cell division, facilitating polyploidy.

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Description

Test your understanding of key concepts from Biology Chapter 24 with these flashcards. This chapter focuses on speciation, anagenesis, and cladogenesis, essential processes in evolutionary biology. Review definitions and examples to enhance your knowledge of how species evolve and diversify.