Textbook Question
Which clade does not include humans?
a. Synapsids
b. Lobe-fins
c. Diapsids
d. Osteichthyans
Ch. 34 - The Origin and Evolution of Vertebrates
Urry11th EditionCampbell BiologyISBN: 9789357423311
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Table of contents
- Ch. 1 - Evolution, the Themes of Biology, and Scientific Inquiry8
- Ch. 2 - The Chemical Context of Life8
- Ch. 3 - Water and Life6
- Ch. 4 - Carbon and the Molecular Diversity of Life9
- Ch. 5 - The Structure and Function of Large Biological Molecules9
- Ch. 6 - A Tour of the Cell6
- Ch. 7 - Membrane Structure and Function6
- Ch. 8 - An Introduction to Metabolism6
- Ch. 9 - Cellular Respiration and Fermentation10
- Ch. 10 - Photosynthesis7
- Ch. 11 - Cell Communication7
- Ch. 12 - The Cell Cycle10
- Ch. 13 - Meiosis and Sexual Life Cycles10
- Ch. 14 - Mendel and the Gene Idea14
- Ch, 15 - The Chromosomal Basis of Inheritance7
- Ch. 16 - The Molecular Basis of Inheritance9
- Ch. 17 - Gene Expression: From Gene to Protein9
- Ch. 18 - Regulation of Gene Expression10
- Ch. 19 - Viruses6
- Ch. 20 - DNA Tools and Biotechnology8
- Ch. 21 - Genomes and Their Evolution8
- Ch. 22 - Descent with Modification: A Darwininan View of Life6
- Ch. 23 - The Evolution of Populations5
- Ch. 24 - The Origin of Species6
- Ch. 25 - The History of Life on Earth6
- Ch. 26 - Phylogeny and the Tree of Life7
- Ch. 27 - Bacteria and Archaea8
- Ch. 28 - Protists7
- Ch. 29 - Plant Diversity I: How Plants Colonized Land7
- Ch. 30 - Plant Diversity II: The Evolution of Seed Plants7
- Ch. 31 - Fungi5
- Ch. 32 - An Overview of Animal Diversity4
- Ch. 33 - An introduction to Invertebrates6
- Ch. 34 - The Origin and Evolution of Vertebrates7
- Ch. 35 - Vascular Plant Structure, Growth, and Development8
- Ch. 36 - Resource Acquisition and Transport in Vascular Plants8
- Ch. 37 - Soil and Plant Nutrition10
- Ch. 38 - Angiosperm Reproduction and Biotechnology8
- Ch. 39 - Plant Responses to Internal and External Signals8
- Ch. 40 - Basic Principles of Animal Form and Function8
- Ch. 41 - Animal Nutrition7
- Ch. 42 - Circulation and Gas Exchange7
- Ch. 43 - The Immune System6
- Ch. 44 - Osmoregulation and Excretion6
- Ch. 45 - Hormones and the Endocrine System8
- Ch. 46 - Animal Reproduction8
- Ch. 47 - Animal Development8
- Ch. 48 - Neurons, Synapses, and Signaling6
- Ch. 49 - Nervous Systems8
- Ch. 50 - Sensory and Motor Mechanisms5
- Ch. 51 Animal Behavior6
- Ch. 52 - An Introduction to Ecology and the Biosphere7
- Ch. 53 - Population Ecology10
- Ch. 54 - Community Ecology9
- Ch. 55 - Ecosystems and Restoration Ecology8
- Ch. 56 - Conservation Biology and Global Change6
Chapter 34, Problem 7
Living members of a vertebrate lineage can be very different from early members of the lineage, and evolutionary reversals (character losses) are common. Give examples that illustrate these observations, and explain their evolutionary causes.
Verified step by step guidance1
Start by understanding the concept of evolutionary reversals, which refers to the loss of a trait that was present in an ancestor. This can occur due to changes in environmental pressures or genetic mutations.
Consider the example of whales, which are part of the vertebrate lineage. Early ancestors of whales were land-dwelling mammals with limbs adapted for walking. Over time, whales evolved to live in aquatic environments, losing their hind limbs as they adapted to swimming.
Another example is the loss of sight in cave-dwelling fish. These fish evolved from ancestors that had functional eyes, but due to living in dark environments where sight is unnecessary, they lost their eyesight over generations.
Discuss the evolutionary causes behind these reversals. Natural selection plays a key role, where traits that are not beneficial in a given environment may be lost over time. Genetic drift can also contribute to the loss of traits, especially in small populations.
Explain how these examples illustrate the dynamic nature of evolution, where organisms continuously adapt to their environments, sometimes resulting in the loss of previously advantageous traits. This highlights the non-linear path of evolutionary change.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Vertebrate Lineage
A vertebrate lineage refers to the evolutionary history and development of vertebrates, which are animals with a backbone. This lineage includes diverse groups such as fish, amphibians, reptiles, birds, and mammals. Over time, these groups have evolved distinct characteristics, adapting to various environments and ecological niches.
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05:27
Vertebrates
Evolutionary Reversals
Evolutionary reversals, or character losses, occur when a species reverts to an ancestral trait, losing a derived characteristic. This can happen due to changes in environmental pressures or genetic mutations. An example is the loss of limbs in snakes, which evolved from lizard-like ancestors, adapting to a burrowing lifestyle where limbs were unnecessary.
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02:45History of Evolutionary Theory Example 1
Evolutionary Causes
Evolutionary changes, including reversals, are driven by natural selection, genetic drift, and mutations. These mechanisms can lead to adaptations that enhance survival and reproduction in specific environments. For instance, the streamlined body of whales evolved from land-dwelling mammals, adapting to aquatic life by losing hind limbs and developing flippers.
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Related Practice
Textbook Question
As hominins diverged from other primates, which of the following appeared first?
a. Reduced jawbones
b. An enlarged brain
c. The making of stone tools
d. Bipedal locomotion
Textbook Question
Which of the following could be considered the most recent common ancestor of living tetrapods?
a. A sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates
b. An armored, jawed placoderm with two pairs of appendages
c. An early ray-finned fish that developed bony skeletal supports in its paired fins
d. A salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes