The statement that the “Cambrian explosion actually consists of three explosions, not one.” Concept introduction : Cambrian explosion refers to the rapid diversification of animals that occurred 535-525 million years ago, during the Paleozoic era. Simple, soft bodied animals also called Ediacaran fauna inhabited the earth before the Cambrian explosion. There are various hypotheses that explain the Cambrian explosion. According to one hypothesis, the appearance of a prey-predator relationship led to the Cambrian explosion. The predators in the Cambrian period acquired novel adaptations for predation. This led to natural selection of prey with hard bodies. The hard bodies helped them in defense from predators. Another hypothesis emphasizes on the increase in atmospheric oxygen. The increase in atmospheric oxygen led to the evolution of animals with high metabolic rate and larger body size. According to another hypothesis, the evolution of Hox genes (developmental genes) and microRNAs led to the evolution of animals with complex bodies. The evidences of first arthropods and chordates come from the rock strata of the Cambrian period.

Question

Want to see the full answer?

Answer 1

Question

Definition Definition Organ system that helps in the digestion of food by mechanical and biochemical processes. The digestive system breaks down food into simpler components that enable the body to then absorb or transport nutrients. The human digestive system includes the gastrointestinal tract or alimentary canal and the associate glands. The organs of the gastrointestinal tract include the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The associated glands include salivary glands, liver, gallbladder, and pancreas.

Chapter 32.4, Problem 3CC

Summary Introduction

To evaluate: The statement that the “Cambrian explosion actually consists of three explosions, not one.”

Concept introduction:

Cambrian explosion refers to the rapid diversification of animals that occurred 535-525 million years ago, during the Paleozoic era. Simple, soft bodied animals also called Ediacaran fauna inhabited the earth before the Cambrian explosion. There are various hypotheses that explain the Cambrian explosion.

According to one hypothesis, the appearance of a prey-predator relationship led to the Cambrian explosion. The predators in the Cambrian period acquired novel adaptations for predation. This led to natural selection of prey with hard bodies. The hard bodies helped them in defense from predators.

Another hypothesis emphasizes on the increase in atmospheric oxygen. The increase in atmospheric oxygen led to the evolution of animals with high metabolic rate and larger body size.

According to another hypothesis, the **evolution of Hox genes (developmental genes) and microRNAs** led to the evolution of animals with complex bodies. The evidences of first arthropods and chordates come from the rock strata of the Cambrian period.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

What are biofertilizers and mention the significance

PCBs and River Otters: Otters in Washington State’s Green-Duwamish River have high levels of polychlorinated biphenyls (PCBs) in their livers. PCBs can bind to the estrogen receptors in animals and disrupt the endocrine system of these otters. The PCBs seem to increase the estrogen to androgen ratio, skewing the ratio toward too much estrogen. How would increased estrogen affect the river otter population? Based on your reading of the materials in this unit, what factors can affect fertility in humans? Explain how each of the factors affecting human fertility that you described can disrupt the human endocrine system to affect reproduction.

Other than oil and alcohol, are there other liquids you could compare to water (that are liquid at room temperature)? How is water unique compared to these other liquids? What follow-up experiment would you like to do, and how would you relate it to your life?

Answer 2

Question

Definition Definition Organ system that helps in the digestion of food by mechanical and biochemical processes. The digestive system breaks down food into simpler components that enable the body to then absorb or transport nutrients. The human digestive system includes the gastrointestinal tract or alimentary canal and the associate glands. The organs of the gastrointestinal tract include the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The associated glands include salivary glands, liver, gallbladder, and pancreas.

Chapter 32.4, Problem 3CC

Summary Introduction

To evaluate: The statement that the “Cambrian explosion actually consists of three explosions, not one.”

Concept introduction:

Cambrian explosion refers to the rapid diversification of animals that occurred 535-525 million years ago, during the Paleozoic era. Simple, soft bodied animals also called Ediacaran fauna inhabited the earth before the Cambrian explosion. There are various hypotheses that explain the Cambrian explosion.

According to one hypothesis, the appearance of a prey-predator relationship led to the Cambrian explosion. The predators in the Cambrian period acquired novel adaptations for predation. This led to natural selection of prey with hard bodies. The hard bodies helped them in defense from predators.

Another hypothesis emphasizes on the increase in atmospheric oxygen. The increase in atmospheric oxygen led to the evolution of animals with high metabolic rate and larger body size.

According to another hypothesis, the **evolution of Hox genes (developmental genes) and microRNAs** led to the evolution of animals with complex bodies. The evidences of first arthropods and chordates come from the rock strata of the Cambrian period.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Answer 3

Question

Definition Definition Organ system that helps in the digestion of food by mechanical and biochemical processes. The digestive system breaks down food into simpler components that enable the body to then absorb or transport nutrients. The human digestive system includes the gastrointestinal tract or alimentary canal and the associate glands. The organs of the gastrointestinal tract include the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The associated glands include salivary glands, liver, gallbladder, and pancreas.

Chapter 32.4, Problem 3CC

Summary Introduction

To evaluate: The statement that the “Cambrian explosion actually consists of three explosions, not one.”

Concept introduction:

Cambrian explosion refers to the rapid diversification of animals that occurred 535-525 million years ago, during the Paleozoic era. Simple, soft bodied animals also called Ediacaran fauna inhabited the earth before the Cambrian explosion. There are various hypotheses that explain the Cambrian explosion.

According to one hypothesis, the appearance of a prey-predator relationship led to the Cambrian explosion. The predators in the Cambrian period acquired novel adaptations for predation. This led to natural selection of prey with hard bodies. The hard bodies helped them in defense from predators.

Another hypothesis emphasizes on the increase in atmospheric oxygen. The increase in atmospheric oxygen led to the evolution of animals with high metabolic rate and larger body size.

According to another hypothesis, the **evolution of Hox genes (developmental genes) and microRNAs** led to the evolution of animals with complex bodies. The evidences of first arthropods and chordates come from the rock strata of the Cambrian period.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Answer 4

Question

Definition Definition Organ system that helps in the digestion of food by mechanical and biochemical processes. The digestive system breaks down food into simpler components that enable the body to then absorb or transport nutrients. The human digestive system includes the gastrointestinal tract or alimentary canal and the associate glands. The organs of the gastrointestinal tract include the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The associated glands include salivary glands, liver, gallbladder, and pancreas.

Chapter 32.4, Problem 3CC

Summary Introduction