Most evolutionary "branches" on the tree of life can read like the story of stepwise challenge and evolutionary innovation. For example, a cuticle solved the problem of maintaining moisture in the first terrestrial plants. Outline and explain the steps

in the evolution of terrestrial vertebrates that lead to the evolution of mammals.

What will be an ideal response?


The story could start with the evolution of lobe-finned fish, because movement on land would be difficult at best without sturdy appendages. Lungs in amphibians and the amniote egg of reptiles eventually allowed independence from the aquatic habitat. Warm-bloodedness, hair, and longer/better care of young after birth (mammary glands) provided additional advantages to mammals over other terrestrial vertebrates.

Biology & Microbiology

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Which of the following is not a correct match?

a. pollen - male b. stigma - female c. anther - female d. ovule - female

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Which is a thyroid hormone produced by many animals that encourages bones to take up and incorporate calcium?

A. Calcitonin B. Glucagon C. Insulin D. Parathyroid E. Melatonin

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The tongue does all of the following except

A) taste food. B) shape food into a ball called a bolus. C) secrete saliva. D) push food into the pharynx.

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Where would you place the actual extinction date of a taxon if you knew that the Signor–Lipps effect was at work?

a. exactly at the date of the last known fossil b. before the date of the last known fossil c. after the date of the last known fossil d. unable to determine when extinction occurred relative to the date of the last known fossil.

Biology & Microbiology