Biology Chapter: Adaptation and Species

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Questions and Answers

What is the primary process through which adaptation occurs?

Genetic drift

Natural selection (correct)

Environment change

Mutation

Which of the following best defines a species according to the biological species concept?

A group that can produce hybrids with other groups

A group that can interbreed and produce fertile offspring (correct)

A group of individuals that can withstand environmental changes

A group with similar morphological traits

Which statement is true regarding the limits of natural selection?

Natural selection operates independently of historical constraints

Only beneficial traits are acted upon by natural selection

Natural selection can predict future adaptations

Natural selection works on existing variations in a population (correct)

What is the first step in the process of speciation?

Genetic isolation Signup and view all the answers

What type of traits provide evidence for speciation based on evolutionary relationships?

Homologous traits Signup and view all the answers

Which of the following describes a condition under which two species can hybridize but are not considered the same species?

Hybrids are sterile or inviable Signup and view all the answers

What aspect of evolution does genetic drift contribute to?

Genetic divergence Signup and view all the answers

Which factor is NOT considered part of natural selection's operation in populations?

Environmental predictions Signup and view all the answers

What process describes the formation of new species from geographically isolated populations?

Allopatric speciation Signup and view all the answers

In which of the following scenarios does genetic divergence primarily occur?

In populations that experience genetic drift and natural selection Signup and view all the answers

Which of the following accurately defines coevolution?

When two species evolve complementary adaptations due to mutual influence Signup and view all the answers

What term is used to describe barriers that prevent individuals from mating or producing viable offspring?

Reproductive barriers Signup and view all the answers

Which statement best defines a species?

A group of populations that can interbreed and produce fertile offspring Signup and view all the answers

Which of the following can create reproductive isolation within a population?

Mating rituals that differ among individuals Signup and view all the answers

What is an example of sympatric speciation?

Two types of Darwin's finches adapting to different food sources on the same island Signup and view all the answers

Which of these adaptations is an example of coevolution?

Floral shapes evolving to attract specific pollinators Signup and view all the answers

Study Notes

Adaptation

Adaptation: An evolutionary process where an organism becomes better suited to its habitat.
It can be a trait advantageous to an individual or a population.

Limits of Natural Selection

Natural selection isn't goal-oriented.
It only acts on existing variations within a population.
It's constrained by inherited traits from ancestors.
Adaptations are also limited by the genetic makeup of individuals.
Mutations create variations.

What is a Species?

Species: A group of organisms that can interbreed and produce fertile offspring.
Biological species concept: A group of natural populations whose members can interbreed to create fertile offspring, but cannot interbreed with other species.
Reproductively isolated from other populations.

Defining "Species"

Biological species concept: Defines species as groups that can interbreed and produce viable offspring.
Hybridization: The process where different species interbreed.
Hybrids are not always viable, meaning they cannot survive or reproduce, which makes them not considered a species.

One Species or Two?

Scientists use biogeographical information, DNA similarities, and morphology (form and structure) to identify and distinguish species.

Speciation

Speciation: The branching off of new species from existing ones.
Evidence of speciation can be found in modern-day organisms.
Evidence includes shared characteristics (homologous traits), DNA similarities and differences, vestigial traits, and patterns of embryo development.

Speciation Stages

Speciation occurs in three stages:
1. Genetic isolation: Through natural selection, genetic divergence (differences in DNA), or mutations.
1. Genetic divergence: Accumulation of differences in DNA.
1. Secondary contact: Confirming speciation.

Genetic Isolation

Geographic isolation: When a barrier prevents populations from interbreeding.
Examples: Mountains, rivers, valleys, canyons.

Genetic Divergence

Genetic divergence: The accumulation of differences in DNA sequences in different populations.
It results in populations becoming increasingly genetically different.
It happens via natural selection, mutations, and genetic drift.

Allopatric Speciation

Allopatric speciation: The formation of new species from geographically isolated populations.
A population gets separated and evolves in different environments.

Sympatric Speciation

Sympatric speciation: The formation of new species in the absence of geographic isolation.
Members of the same species start diverging in their behavioral traits, often leading to a reproductive barrier.

Reproductive Barriers

Reproductive barriers isolate species in the same geographic area.
Prezygotic barriers prevent the formation of a zygote.
Postzygotic barriers operate after the zygote forms.

Coevolution

Coevolution: When the interaction between two species significantly influences their survival, causing reciprocal adaptation.
An adaptation in one species leads to a complementary adaptation in another species.

Recap - Examples

Buff-tailed sicklebill hummingbirds' specifically shaped bill to match the flower shape it feeds on is an example of coevolution.
Horses and donkeys being different species despite being able to have offspring (infertile mules) because viable offspring are needed for the species designation is an example.
What is a Species?: A group of similar individuals who live in one geographic area and interbreed; producing fertile offspring is an example.
What creates Reproductive Isolation: Mating rituals, rapid and severe changes in geographic features, and gamete incompatibility are examples.

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Description

Explore the concepts of adaptation, natural selection, and species definition in this quiz. Understand how organisms evolve and the limits of natural selection. Test your knowledge on the biological species concept and hybridization.