/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 9 The biological species concept ... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 15: Problem 9

The biological species concept a. can be applied to organisms that reproduce asexually. b. can be applied to fossil life-forms. c. would classify two natural populations, A and B, as separate species if \(\mathrm{A}\) and \(\mathrm{B}\) were separated by a geographic barrier. d. would classify two natural populations, \(A\) and \(B\), as separate species if \(\mathrm{A}\) and \(\mathrm{B}\) were unable to exchange genes even if they cooccurred.

Short Answer

Expert verified
Option d is correct: two populations are separate species if they can't exchange genes even when co-occurring.

Step by step solution

01

Definition Of Biological Species Concept

The biological species concept defines a species as a group of individuals that can interbreed and produce fertile offspring under natural conditions. It emphasizes the ability to exchange genes and reproductive isolation.
02

Consideration Of Asexual Reproduction

The biological species concept is based on sexual reproduction; hence option a is incorrect as it cannot be applied to organisms that reproduce asexually.
03

Consideration Of Fossil Life-Forms

The biological species concept is not applicable to fossils, as they are not available for genetic testing or reproduction; hence option b is incorrect.
04

Analysis Of Geographic Isolation

Populations separated by a geographic barrier may still belong to the same species if the barrier is removed and they can interbreed. Therefore, option c is incorrect because geographic separation alone does not classify them as separate species.
05

Examine Gene Exchange Possibilities

According to the biological species concept, if two populations, A and B, cannot exchange genes even when they are in the same location, they are classified as separate species. Therefore, option d is correct.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Reproductive Isolation
Reproductive isolation is a fundamental aspect of the biological species concept. It refers to various barriers that prevent different populations from interbreeding. These barriers are crucial because they maintain the genetic individuality of species. Reproductive isolation can occur in several ways:
  • Prezygotic barriers: These are obstacles that prevent mating or fertilization between populations. They include things like differing mating seasons or mechanisms and habitat differentiation.
  • Postzygotic barriers: These occur after fertilization and can lead to problems like offspring that are infertile or have reduced viability.
  • Behavioral isolation: Variations in mating rituals or preferences can also prevent interbreeding.
Reproductive isolation is essential for the development of new species as it ensures gene flow barrier between diverging populations.
Asexual Reproduction
Unlike sexual reproduction, asexual reproduction involves only one parent. This process results in offspring that are genetically identical to the parent. Because the biological species concept focuses on the ability to reproduce sexually, it does not apply to organisms that reproduce asexually. This presents a unique challenge in categorizing asexual organisms into species. Asexual reproduction can occur through several mechanisms:
  • Budding: A new individual grows from a certain part of the parent and eventually detaches.
  • Binary fission: The organism divides into two or more parts, each growing into an independent organism.
  • Spores: Some organisms produce spores, which are capable of growing into a new organism under the right conditions.
In asexually reproducing organisms, species classification often relies on morphological or ecological factors instead of the biological species concept.
Fossil Life-Forms
Fossils provide a window into the past, offering insights into ancient life-forms. However, they pose a challenge to the biological species concept as they cannot be tested for their ability to interbreed. Since genetic material typically isn't preserved in fossils, scientists rely on anatomical features and context within the rock record to hypothesize about species relationships. Several methods are used to study fossil life-forms:
  • Morphological analysis: Looking at the shape and structure of fossils to determine possible species.
  • Paleobiogeography: Understanding the distribution of species over time to infer possible ecological and evolutionary relationships.
  • Comparative anatomy: Comparing fossilized remains to modern organisms to hypothesize evolutionary connections.
Although the biological species concept is not directly applicable, these approaches allow scientists to identify and classify extinct species based on the available evidence.
Gene Exchange
Gene exchange is a key feature in defining a species according to the biological species concept. It refers to the transfer of genetic material between populations, which can occur through various mechanisms. Successful gene exchange leads to genetic cohesion within a species, ensuring that any genetic advantages spread throughout the population. Gene exchange occurs through mechanisms such as:
  • Sexual reproduction: The primary means of gene exchange in many species, involving the combination of genetic material from two parents to produce genetically diverse offspring.
  • Horizontal gene transfer: Mostly found in bacteria, this involves direct transfer of DNA from one organism to another without reproduction.
  • Hybridization: Occurs when two different species interbreed. If the offspring are fertile, it can lead to gene flow between the two parent species.
When gene exchange between two populations is hindered, they are often classified as separate species under the biological species concept.
Geographic Isolation
Geographic isolation occurs when physical barriers prevent populations from interacting. It is a significant factor in the formation of new species, as it restricts gene flow between separated groups. The biological species concept considers that geographic isolation alone doesn't necessarily result in the formation of new species unless it leads to reproductive isolation over time. Examples of geographic isolation include:
  • Mountains and rivers: Natural barriers that can separate populations, preventing them from interbreeding.
  • Ocean and deserts: Vast expanses can isolate populations, especially for organisms not adapted to these environments.
  • Human-made structures: Urban development can also contribute to geographic isolation by fragmenting habitats.
The removal of these barriers can lead to reunification and potential interbreeding, but if the populations have diverged significantly in isolation, they could remain distinct species despite the absence of geographic barriers.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The diploid number of chromosomes in plant species \(\mathrm{A}\) is 8 ; the diploid number in plant species \(\mathrm{B}\) is 16 . If plant species \(\mathrm{C}\) originated when a hybrid between \(\mathrm{A}\) and \(\mathrm{B}\) spontaneously doubled its chromosome number, what is the most likely number of diploid chromosomes in \(\mathrm{C} ?\) a. 8 b. 12 c. 24 d. 48

The time required for populations to diverge to form new species a. varies from a single generation to millions of years. b. is always greater in plants than in animals. c. is never less than 100,000 years. d. is never more than 1,000 years.

Evidence suggests that sympatric speciation may have occurred or may be in progress in all of the following cases except a. the apple maggot fly. b. squirrels on opposite sides of the Grand Canyon. c. cichlid fishes. d. polyploid plants (or their ancestors).

Which of the following evolutionary mechanisms acts to slow down or prevent the evolution of reproductive isolation? a. natural selection b. gene flow c. mutation d. genetic drift

Species that have overlapping geographic ranges but do not interbreed in nature are said to be a. geographically isolated. b. reproductively isolated. c. influenced by genetic drift. d. hybrids.
See all solutions

Recommended explanations on Biology Textbooks

Responding to Change

Read Explanation

Biological Molecules

Read Explanation

Chemistry of Life

Read Explanation

Bioenergetics

Read Explanation

Astrobiological Science

Read Explanation

Energy Transfers

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.