Biology Chapter 22 Flashcards

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Questions and Answers

What is the best cause and effect sequence for the process of speciation by natural selection?

Variation --> Mutation --> Speciation --> Reproductive Isolation --> Selection

Mutation --> Variation --> Selection --> Reproductive Isolation --> Speciation (correct)

Reproductive Isolation --> Variation --> Mutation --> Selection --> Speciation

Selection --> Mutation --> Variation --> Reproductive Isolation --> Speciation

What is an example of temporal isolation?

One plant species blooms in June-July and a second plant species blooms in August-September.

What type of isolating mechanism is represented by males of many marsupial species having forked penises incompatible with female placental mammals?

Mechanical incompatibility.

The means of isolation for two species of wild lettuce that bloom at different seasons is?

Prezygotic and temporal. Signup and view all the answers

According to the __________ species concept, a species is comprised of populations in which members mate with each other and produce fertile offspring.

biological Signup and view all the answers

Members of different species cannot interbreed successfully due to _______ _ _______.

reproductively isolating mechanisms Signup and view all the answers

Match the species concepts with their descriptions:

Biological Species Concept = Species as populations that interbreed and produce fertile offspring Ecological Species Concept = Species adapted to their specific environments Signup and view all the answers

What is another term for environmental isolation?

Ecological isolation. Signup and view all the answers

What does speciation of geographically isolated populations often prevent?

Gene flow. Signup and view all the answers

What is polyploidy?

The state of a cell or organism having more than two paired sets of chromosomes. Signup and view all the answers

What contributed to the adaptive radiation of Darwin's finches on the Galápagos Islands?

Lack of mainland bird types, geographic isolation, vacant ecological niches. Signup and view all the answers

What is reproductive isolating mechanisms?

Mechanisms that prevent interbreeding between different species. Signup and view all the answers

Sympatric speciation occurs with geographic separation.

False Signup and view all the answers

Mechanical isolation refers to differences in courtship rituals that prevent mating.

False Signup and view all the answers

What is hybrid sterility?

An isolating mechanism resulting in hybrids that are sterile. Signup and view all the answers

What process can promote speciation through random changes between isolated populations?

Genetic drift Signup and view all the answers

Study Notes

Speciation and Natural Selection

Speciation by natural selection follows the sequence: Mutation → Variation → Selection → Reproductive Isolation → Speciation.
Biological species concept defines a species as populations that interbreed and produce fertile offspring.

Isolation Mechanisms

Temporal isolation occurs when species reproduce at different times, as seen in two plant species blooming in different seasons.
Mechanical incompatibility exists when anatomical differences prevent successful mating, such as marsupial males with specialized penises that don't fit female placental anatomy.
Prezygotic isolating mechanisms prevent hybrid zygote formation, while postzygotic mechanisms prevent survival or reproduction of hybrids.

Examples of Isolation

Blue-footed boobies exhibit behavioral isolation through unique courtship displays.
Hybrid inviability example: Mules are sterile hybrids of horses and donkeys.
Two wild lettuce species demonstrate temporal isolation as they bloom in different seasons, preventing hybridization.

Types of Speciation

Sympatric speciation occurs without geographic separation, often through mechanisms like polyploidy in plants, where offspring have more than two sets of chromosomes.
Disruptive selection can promote sympatric speciation by favoring different phenotypes over generations.

Adaptive Radiation

Adaptive radiation refers to one species evolving into many, adapting to different habitats within a region.
Character displacement is the process where closely related species evolve distinct traits to reduce competition.

Ecological Isolation

Ecological isolation occurs when species share the same area but occupy different habitats, reducing encounters.
Examples include lions and tigers that overlap in range but inhabit different environments.

Reproductive Isolation

Reproductive isolating mechanisms prevent interbreeding among different species, fostering the integrity of distinct species.
Criticisms of the biological species concept include its limitations with geographically separated populations and asexual organisms.

Reinforcement Mechanisms

Reinforcement solidifies incomplete isolating mechanisms through natural selection, improving species separation over time.
Incomplete mechanisms may allow hybrid formation, but hybrids can be inferior or sterile.

Genetic Drift and Variation

Genetic drift can lead to speciation through random changes in isolated populations, influencing genetic diversity.
Geographic variation within a species can result in distinct populations that remain connected through intermediate characteristics.

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Description

Test your knowledge on the key concepts from Chapter 22 of Biology, focusing on speciation and natural selection. This set of flashcards covers essential terms and examples, helping you understand reproductive isolation and temporal isolation among species.