Question

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In Europe , three lineages of bears evolved in a common ancestor. Two of those lineages led to present-day black bears and brown bears. The Third lineages led to cave bears that went extinct 24,000 years ago. Which of the following could explain why only one group of bears were extinct?

Answer 1

A. Individual cave bears must not have been able to adapt to changing condition as quickly as brown and black bears.
B. One group of bears was less highly evolved less than the two other groups and was destined to die out.
C. Some environmental change severely threatened cave bear survival but not the survival of brown or black bears.
D. Random chance led to the extinction of cave bears and survival or brown and black bears.

Answer 2

I would say either A or C. Both make sense but I am leaning more towards A. considering they all lived in Europe and probably in the same area so the environment couldn't have been very different.

Answer 3

@SummerNS Thank you! Help me with some more?!?

Answer 4

Sure

Answer 5

Awesome! Thank you<3

Suppose a scientist found a new fossil that indicated it was a primitive mammal. Relative dating techniques place the age of this fossil at a much earlier time than mammals were thought to exist. What effect will this finding have on understanding of the history of life.

Answer 6

A. The Split between mammals and nonmammals in the tree of life need to be shifted back.
B. A new branch needs to be added to the tree of life.
C. An existing branch on the tree life needs to be removed.
D. Other fossils need to be rested to be sure that the ages assigned to them are not in error

Answer 7

Hm..D sounds the most accurate. B might be right too.. I'm not entirely sure but I lean more towards D.

Answer 8

Thanks(:

Answer 9

No problem. Have anymore?

Answer 10

Yeah, if you don't mind.

Answer 11

Definitely not. I plan on taking Bio in college so I love to do this.

Answer 12

Awesome, thanks!

Answer 13

Which of the following must occur speciation to take place.

A. A population must be physically separated into two or more groups.
B. Harsh Environmental conditions must be imposed on a population.
C. Competition must occur between members of population.
D. Some event must occur leading to two or more groups within a population that cannot be interbreed

Answer 14

So speciation is the formation of new and distinct species in the course of evolution. For speciation to take place the population must be separated in some way. So it would be A.

Answer 15

Thank you! Help me with one more!?

A population of snails on a island disrupted during a violent storm. Portions of the population are carried by the surge to two new islands, while a portion remains on the original island, creating three separate populations. Conditions on one of the new islands are exactly like conditions on the original island. Conditions on one of the new islands are exactly like conditions to one of the original island. However, snails that landed on the second new island encounter various new predator. What is likely to happen to these three populations?

Answer 16

A. Speciation will occur at the same rate in all three snail population.
B. Spectation will occur at the same rate in the snails that landed on new islands but not in the original snail position.
C. Speciation will rapidly occur in one of the snail populations that landed on new islands but not in the other two snail populations
D. Speciation will occur in the original snail population but will not occur in the populations that landed on new islands

Answer 17

It would be C because only one landed on an island that was different.

Answer 18

Thank you(:

Answer 19

Anytime, really.