Textbook Question
Propose an explanation for why annelids and arthropods were thought to be closely related, before phylogenetic analyses in the late 1990s.
911
views
Ch. 31 - Protostome Animals
Freeman7th EditionBiological ScienceISBN: 9783584863285
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch. 1 - Biology: The Study of Life11
- Ch. 2 - Water and Carbon: The Chemical Basis of Life10
- Ch.3 - Protein Structure and Function11
- Ch.4 - Nucleic Acids and the RNA World10
- Ch. 5 - An Introduction to Carbohydrates10
- Ch. 6 - Lipids, Membranes, and the First Cells10
- Ch. 7 - Inside the Cell10
- Ch. 8 - Energy and Enzymes: An Introduction to Metabolism10
- Ch. 9 - Cellular Respiration and Fermentation16
- Ch. 10 - Photosynthesis14
- Ch. 11 - Cell-Cell Interactions14
- Ch. 12 - The Cell Cycle12
- Ch. 13 - Meiosis13
- Ch. 14 - Mendel and the Gene32
- Ch. 15 - DNA and the Gene: Synthesis and Repair8
- Ch. 16 - How Genes Work35
- Ch. 17 - Transcription, RNA Processing, and Translation16
- Ch. 18 - Control of Gene Expression in Bacteria19
- Ch. 19 - Control of Gene Expression in Eukaryotes17
- Ch. 20 - The Molecular Revolution: Biotechnology, Genomics, and New Frontiers23
- Ch. 21 - Genes, Development, and Evolution13
- Ch. 22 - Evolution by Natural Selection17
- Ch. 23 - Evolutionary Processes13
- Ch. 24 - Speciation15
- Ch. 25 - Phylogenies and the History of Life13
- Ch. 26 - Bacteria and Archaea17
- Ch. 27 - Diversification of Eukaryotes19
- Ch. 28 - Green Algae and Land Plants18
- Ch. 29 - Fungi19
- Ch. 30 - An Introduction to Animals9
- Ch. 31 - Protostome Animals20
- Ch. 32 - Deuterostome Animals19
- Ch. 33 - Viruses16
- Ch. 34 - Plant Form and Function16
- Ch. 35 - Water and Sugar Transport in Plants16
- Ch. 36 - Plant Nutrition13
- Ch. 37 - Plant Sensory Systems, Signals, and Responses16
- Ch. 38 - Flowering Plant Reproduction and Development16
- Ch. 39 - Animal Form and Function16
- Ch. 40 - Water and Electrolyte Balance in Animals16
- Ch. 41 - Animal Nutrition16
- Ch. 42 - Gas Exchange and Circulation16
- Ch. 43 - Animal Nervous Systems16
- Ch. 44 - Animal Sensory Systems16
- Ch. 45 - Animal Movement11
- Ch. 46 - Chemical Signals in Animals16
- Ch. 47 - Animal Reproduction and Development18
- Ch. 48 - The Immune System in Animals16
- Ch. 49 - An Introduction to Ecology16
- Ch. 50 - Behavioral Ecology16
- Ch. 51 - Population Ecology16
- Ch. 52 - Community Ecology20
- Ch. 53 - Ecosystems and Global Ecology16
- Ch. 54 - Biodiversity and Conservation Ecology16
Chapter 31, Problem 8
Which of these choices is an example of homology (similarity due to common ancestry)?
a. Suspension feeding in sponges and clams
b. Ectoparasite lifestyle in aphids and ticks
c. Cnidocytes (stinging cells) in jellyfish and sea anemones
d. Radial symmetry in cnidarians and echinoderms
Verified step by step guidance1
Understand the concept of homology: Homology refers to similarities between organisms that arise from a common ancestor. These traits are inherited from a shared ancestor and may serve different functions in the descendants.
Analyze each choice to determine if the trait is due to common ancestry: For each option, consider whether the trait is likely inherited from a common ancestor or if it evolved independently.
Option a: Suspension feeding in sponges and clams. Consider the evolutionary history of sponges and clams. They belong to different phyla, and their suspension feeding mechanisms evolved independently, not due to common ancestry.
Option b: Ectoparasite lifestyle in aphids and ticks. Aphids and ticks are from different classes and have independently evolved to be ectoparasites, so this is not an example of homology.
Option c: Cnidocytes in jellyfish and sea anemones. Both jellyfish and sea anemones are part of the phylum Cnidaria, and cnidocytes are a characteristic feature of this phylum, indicating a common ancestry. This is an example of homology.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Homology
Homology refers to the similarity in characteristics resulting from shared ancestry. It is a fundamental concept in evolutionary biology, indicating that certain traits or structures in different species have evolved from a common ancestor. Homologous structures may serve different functions but share a similar underlying anatomy.
Recommended video:
Guided course
08:09
Homologous Chromosomes
Cnidocytes
Cnidocytes are specialized cells found in cnidarians, such as jellyfish and sea anemones, used for capturing prey and defense. These cells contain organelles called nematocysts, which can deliver a sting to potential threats or prey. The presence of cnidocytes in both jellyfish and sea anemones suggests a common evolutionary origin, making them an example of homology.
Recommended video:
Guided course
10:21Porifera and Cnideria
Radial Symmetry
Radial symmetry is a form of symmetry where body parts are arranged around a central axis, common in organisms like cnidarians and echinoderms. While radial symmetry is a shared trait, it is not necessarily due to common ancestry, as it can arise independently in different evolutionary lineages. Thus, it is not an example of homology but rather convergent evolution.
Recommended video:
Guided course
04:31Overview of Animals - 4
Related Practice
Textbook Question
Use your understanding of insect evolution to predict two adaptations for terrestrial living that occurred in spiders.
714
views
Textbook Question
Pose a hypothesis to explain why the evolution of the wing was such an important event in the evolution of insects.
680
views
Textbook Question
Evaluate this statement: Evolution is said to occur when new traits accumulate over time, increasing complexity.
639
views
Textbook Question
Brachiopoda is a phylum within the Lophotrochozoa. Even though they are not closely related to bivalve mollusks (such as clams or mussels), brachiopods look and act like bivalve mollusks. Specifically, brachiopods suspension feed, secrete calcium carbonate shells with two valves that hinge together in some species, and attach to rocks or other hard surfaces on the ocean floor. How is it possible for brachiopods and bivalves to be so similar if they did not share a recent common ancestor?
710
views
Textbook Question
Suppose that a gene originally identified in nematodes (roundworms) is found to be homologous with a gene that can cause developmental abnormalities in humans. Would it be possible to use fruit flies as a model organism to study this gene? Explain.
810
views