Textbook Question
Which protostome phyla successfully made the transition from water to land? Select True or False for each phylum.
T/FMollusca
T/FArthropoda
T/FAnnelida
T/FNematoda
Ch. 31 - Protostome Animals
Freeman8th EditionBiological ScienceISBN: 9780138276263
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Table of contents
- Ch. 1 - Biology: The Study of Life13
- Ch. 2 - Water and Carbon: The Chemical Basis of Life14
- Ch.3 - Protein Structure and Function10
- Ch.4 - Nucleic Acids and the RNA World10
- Ch. 5 - An Introduction to Carbohydrates10
- Ch. 6 - Lipids, Membranes, and the First Cells11
- Ch. 7 - Inside the Cell10
- Ch. 8 - Energy and Enzymes: An Introduction to Metabolism10
- Ch. 9 - Cellular Respiration and Fermentation11
- Ch. 10 - Photosynthesis12
- Ch. 11 - Cell-Cell Interactions12
- Ch. 12 - The Cell Cycle8
- Ch. 13 - Meiosis12
- Ch. 14 - Mendel and the Gene23
- Ch. 15 - DNA and the Gene: Synthesis and Repair15
- Ch. 16 - How Genes Work16
- Ch. 17 - Transcription, RNA Processing, and Translation16
- Ch. 18 - Control of Gene Expression in Bacteria16
- Ch. 19 - Control of Gene Expression in Eukaryotes12
- Ch. 20 - The Molecular Revolution: Biotechnology, Genomics, and New Frontiers15
- Ch. 21 - Genes, Development, and Evolution12
- Ch. 22 - Evolution by Natural Selection16
- Ch. 23 - Evolutionary Processes13
- Ch. 24 - Speciation15
- Ch. 25 - Phylogenies and the History of Life13
- Ch. 26 - Bacteria and Archaea15
- Ch. 27 - Diversification of Eukaryotes16
- Ch. 28 - Green Algae and Land Plants16
- Ch. 29 - Fungi18
- Ch. 30 - An Introduction to Animals9
- Ch. 31 - Protostome Animals15
- Ch. 32 - Deuterostome Animals17
- 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 Function17
- 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 Development16
- Ch. 48 - The Immune System in Animals16
- Ch. 49 - An Introduction to Ecology15
- Ch. 50 - Behavioral Ecology16
- Ch. 51 - Population Ecology16
- Ch. 52 - Community Ecology20
- Ch. 53 - Ecosystems and Global Ecology17
- Ch. 54 - Biodiversity and Conservation Ecology18
Chapter 31, Problem 5
Propose an explanation for why annelids and arthropods were thought to be closely related, before phylogenetic analyses in the late 1990s.
Verified step by step guidance1
Identify the similarities between annelids and arthropods that led to the initial assumption of close relation, such as segmented bodies, presence of a coelom, and a similar nervous system structure.
Discuss the concept of convergent evolution, where unrelated species independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.
Explain the role of traditional taxonomy based on morphological characteristics, which might have emphasized visible similarities and overlooked genetic differences.
Introduce the impact of molecular and genetic data obtained in the late 1990s, which provided new insights into evolutionary relationships through DNA analysis, leading to a reevaluation of the phylogenetic tree.
Clarify the current understanding based on molecular phylogenetics, which shows that annelids and arthropods are not as closely related as previously thought, belonging to different clades within the Protostomia.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Annelid and Arthropod Morphology
Annelids, such as earthworms, and arthropods, like insects and crustaceans, share several morphological features, including segmented bodies and similar organ systems. This segmentation led early biologists to group them together, as both exhibit a division of labor among body segments, which was thought to indicate a close evolutionary relationship.
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Guided course
06:14
Annelids
Common Ancestry and Evolutionary Relationships
Before the advent of molecular phylogenetics, scientists relied heavily on morphological characteristics to infer evolutionary relationships. The similarities in body structure and developmental patterns between annelids and arthropods suggested a common ancestor, leading to the hypothesis that they diverged from a shared lineage.
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02:45History of Evolutionary Theory Example 1
Phylogenetic Analysis
Phylogenetic analysis involves the use of genetic data to construct evolutionary trees that depict relationships among species. In the late 1990s, advancements in molecular techniques allowed for more accurate assessments of these relationships, revealing that annelids and arthropods are not as closely related as previously thought, challenging earlier morphological classifications.
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04:13Building Phylogenetic Trees Example 2
Related Practice
Textbook Question
Use your understanding of insect evolution to predict two adaptations for terrestrial living that occurred in spiders.
Textbook Question
Pose a hypothesis to explain why the evolution of the wing was such an important event in the evolution of insects.
Textbook Question
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
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