Mod B Unit 1, Les 3 Evidence Of Evolution

Question 1

What are fossils?

Answer 1

the remains or imprints of once-living organisms

Question 2

How do you know how old a fossil is when you examine the rock layers it is found in?

Answer 2

The lower the rock layer, the older the fossil is since new rock layers form below old ones

Question 3

How are fossils usually formed?

Answer 3

1. Dead organisms are covered by a layer of sediment or mud
2. Sediment settles over time, more layers build above it
3. Minerals replace the dead organism and harden, making a “cast fossil”

Question 4

What is the fossil record?

Answer 4

All of the fossils that have been discovered over time. It gives evidence of the order that species have existed and changed over time. It teaches us the history of life over time

Question 5

Why is the fossil record incomplete?

Answer 5

Most organisms die and decompose. They go back into the biological world.

Question 6

What are transitional fossils? (See p. 31 for photo)

Answer 6

These fossils help fill the gaps in the fossil record

Question 8

What evidence is there to support the idea of evolution? (3 answers)

Answer 8

1. Common structure in organisms (similar body parts)
2. Similar DNA
3. Developmental similarities (looking at embryology)

Question 9

One evidence of evolution is “common structures” (body parts) in organisms. Give examples of this from your text. (P. 32)

Answer 9

1. Human arm bones, a cat’s front leg, and wings of bats don’t look alike but are similar in structure. They may have a common ancestor
2. Snakes have traces of leg like structures that are no longer used showing they may have a common ancestor with lizards.

Question 10

Another example of evidence of evolution is “similar DNA”. How does similar DNA support the idea of evolution?

Answer 10

Because an organism’s DNA stays almost the same throughout its life time, scientists can compare them. The greater the similarities, the more recently they shared a common ancestor. (Scientists look at the amino acids p. 33)

Question 11

Another example of evidence of evolution is “developmental similarities with embryology”. How does this support the idea of evolution?

Answer 11

They look at embryo’s development and changes. If they develop in similar ways, they probably share a common ancestor.
Example: all animals with backbones have evidence of a tail. They share a common ancestor.

Question 12

Which word means “The history of life in the geologic past as indicated by the imprints or remains of living things”?

Answer 12

Evolution

Question 18

What is meant by a common ancestor?

Answer 18

The most recent species from which two different species have evolved.