Evolution - Biological Species Concept

Questions and Answers

Define the biological species concept.

Scientists categorize organisms into species based on their physical, genetic, and behavioral characteristics. The biological species concept defines a species as a population of organisms that can interbreed to produce viable, fertile offspring.

List alternative species concepts.

Morphological, phylogenetic, and ecological species concepts.

Explain the role of reproductive isolation in the evolution of species.

Reproductive isolation occurs when part of a population becomes isolated from its parent population, leading to independent mutation, genetic drift, and natural selection.

Distinguish between prezygotic and postzygotic barriers.

Prezygotic barriers prevent mating or fertilization, while postzygotic barriers occur after fertilization, resulting in infertile or non-viable offspring. Signup and view all the answers

Distinguish between macroevolution and microevolution.

Macroevolution refers to the evolution of adaptations shared by many species from a common ancestor, while microevolution occurs within a species at the population level without forming new species. Signup and view all the answers

What is binomial nomenclature?

A system for naming species established by Carl Linnaeus. Signup and view all the answers

What is a clade?

A group consisting of a common ancestor and all of its descendants. Signup and view all the answers

What is the ecological species concept?

It uses information about the niche to distinguish between different species. Signup and view all the answers

What is gametic isolation?

A prezygotic barrier to reproduction whereby copulation occurs but sperm and eggs are incompatible. Signup and view all the answers

Define habitat in the context of species.

An ecological area where a species survives and reproduces. Signup and view all the answers

What is a hybrid?

An offspring resulting from the mating of individuals of different species. Signup and view all the answers

What is hybrid breakdown?

Offspring of a cross (F1) capable of reproducing, but their subsequent offspring (F2) are infertile. Signup and view all the answers

What is mechanical isolation?

A prezygotic barrier to reproduction due to incompatibility of structures involved in gamete transfer. Signup and view all the answers

What is a monophyletic group?

A group where each population evolved from a common ancestral species. Signup and view all the answers

What does the morphological species concept emphasize?

It emphasizes structural features in determining recent common ancestors. Signup and view all the answers

What does the phylogenetic species concept emphasize?

It emphasizes genetic makeup when determining if there is a recent common ancestor. Signup and view all the answers

Define population in biological terms.

Multiple individuals of the same species living in the same general area. Signup and view all the answers

What is a postzygotic barrier?

A barrier to reproductive success whereby gametes form a zygote but offspring are infertile or not viable. Signup and view all the answers

What is a prezygotic barrier?

Reproductive isolation in which barriers prevent mating, including behavioral, physical, physiological, and mechanical barriers. Signup and view all the answers

Study Notes

Biological Species Concept

Defines species as populations that can interbreed to produce viable, fertile offspring.
Prioritizes physical, genetic, and behavioral characteristics for classification.

Alternative Species Concepts

Includes morphological, phylogenetic, and ecological species concepts.
Each concept highlights different criteria for defining species but is less commonly used than the biological species concept.

Reproductive Isolation

Occurs when part of a population becomes isolated, leading to independent evolution through mutation, genetic drift, and natural selection.
Over time, isolated populations may develop reproductive barriers.

Prezygotic vs. Postzygotic Barriers

Prezygotic barriers: Prevent mating or fertilization (e.g., behavioral differences, mechanical incompatibility).
Postzygotic barriers: Impact offspring after fertilization (e.g., hybrids may be sterile or inviable).
Both types contribute to genetic isolation and speciation.

Macroevolution vs. Microevolution

Macroevolution: Evolutionary changes that produce new species from common ancestors.
Microevolution: Small adaptations within a species that do not lead to the formation of new species.

Binomial Nomenclature

Developed by Carl Linnaeus, system names species with two parts: genus and species.

Clade

A group that includes a common ancestor and all of its descendants.
Represents a branch on a phylogenetic tree.

Ecological Species Concept

Defines species based on ecological niche and role in the ecosystem.

Gametic Isolation

A prezygotic reproductive barrier where sperm and eggs are incompatible, preventing fertilization.

Habitat

The ecological area where a species lives, survives, and reproduces.

Hybrid

An offspring resulting from mating between individuals of different species.

Hybrid Breakdown

F1 hybrids can reproduce, but F2 offspring are typically infertile.

Mechanical Isolation

A prezygotic barrier due to physical incompatibility in reproductive structures.

Monophyletic Group

A group of species that all descended from a common ancestor.

Morphological Species Concept

Emphasizes structural features for determining species and common ancestry.

Phylogenetic Species Concept

Focuses on genetic characteristics to identify species and their common ancestry.

Population

A group of individuals from the same species residing in a specific area.

Postzygotic Barrier

A barrier preventing successful reproduction where fertilization occurs but leads to infertile or non-viable offspring.

Prezygotic Barrier

Encompasses various forms of reproductive isolation preventing mating, including behavioral and mechanical barriers.

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Description

This quiz covers the biological species concept and alternative species concepts in detail. It is designed to enhance your understanding of how scientists differentiate between species based on various characteristics. Test your knowledge on the definitions and implications of these concepts.