Exam 15: A Brief History of Life on Earth

Mass extinctions in geologic history are attributed to many possible causes.What are some of these proposed causes?

The characteristic animals of the Cambrian Period,as shown below,which left some of the oldest skeletal fossils,were _____.

Dinosaurs included the largest land animals that ever lived.

The first terrestrial vertebrates,which never became completely free from water habitat,were _____.

The most devastating of all mass extinction events occurred at the end of the Paleozoic Era (Permian Period)around _____ million years ago.

Eukaryotes are recognizableas distinct from prokaryotes because they all have _____,_____,and ____.

The "Cambrian Explosion" refers to _____.

In order for mammalian life to succeed,oxygen levels as shown in the graph of at least ______ percent are required.

Which of the following is NOT a critical need for life on land?

All fossils are altered as they are preserved.

Organisms that live in harsh environments,such as the edges of black smokers on the seafloor,are ______.

The Burgess shale and Chengjiang Biota are famous for their preservation of soft-bodied animals (alternatively,nonmineralized or nonskeletonized).

Which of the following is NOT one of the three Domains of Life recognized by biologists?

The oldest hominids that were definitely bipedal were in the genus _____.

Fossilized feces are termed _____.

Which of the following is NOT a way in which organisms obtain energy _____.

Which of the following is NOT a credible hypothesis for the rapid diversification of Cambrian life?

Molecular oxygen in the atmosphere originated mostly from plants,as shown below,as a by-product of _____.

What is volcanic outgassing and why is it important?

The basic difference between gymnosperm and angiosperm plants (as shown below),is the development of _____in the latter.