Concept explainers
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
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.
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EBK CAMPBELL BIOLOGY
- What caused the Cambrian explosion? Describe current hypotheses.arrow_forwardHello, I need help with number 3 a, b, & c using the diagram below. Pls & thank you! 3. a) What features does the organism shown above have that indicate that it is our direct ancestor among the Cambrian fauna? 3. b) When the organism shown above was swimming in the Cambrian seas, it was very small compared to the apex predator (Anomalocaris), which was several feet long. What adaptations might the organism shown above have to evade predation by Anomalocaris? 3. c) A famous evolutionary biologist says that “everything in evolution is contingent”, which he explains means that events could always have turned out differently. Do you think that the survival of our direct ancestor is an example of a lucky accident that allowed the later evolution of vertebrates, including us? Why or why not? Photos reference: Futuyma, D. J., & Kirkpatrick, M. (2017). Chapter 17 The History of Life. In Evolution (4th ed., pp. 430-467). Sunderland, Massachusetts: Sinauer Associates.arrow_forwardThe Cambrian explosion is a conundrum: how can the long prior history of the phyla, revealed by molecular divergence, be reconciled with their absence, and then sudden appearance, in the fossil record?arrow_forward
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