Unit B: Evolution & DNA

Full Name: ______________________
Date: ____________ Period: ____
Unit B: Evolution & DNA
Checkpoint: ch#15 – Darwin’s Theory of Evolution
Instructions: please answer the questions in full sentences.
1) Explain what is meant by the term evolution, and give an example.
Evolution, or change over time, is the process
by which modern organisms have descended
from ancient organisms. An example is a
population of predators in which the fastest
animals passed on their traits (all the traits, as
well as being fast) to new generations.
2) Describe where the Galapagos Islands are located. How did the visit to
the Galapagos Islands affect Darwin’s thoughts on evolution? Please
describe the living organisms, that Darwin observed on the Galapagos
Islands, that helped support his thoughts on evolution.
The Galapagos Islands are located many kilometres
off the northwest coast of South America. Darwin’s
visit to the Galapagos Islands convinced him that new
species might arise from existing species over time.
Each Galapagos Island had very different habitats.
Darwin observed that different tortoises and different
birds (finches in particular) lived on each Galapagos
3) How did Hutton’s and Lyell’s Views of Earth differ from that of most
people in their time?
Hutton proposed that Earth had to be millions – not
thousands – of years old.
Lyell argued that the same forces (such as plate
tectonics, movement of the continental plates) change
Earth in the present as in the past, so scientists
should explain Earth’s history in terms of processes
that are observable in the present.
4) a) Explain Lamarck’s principle of use and disuse.
b) Use an example to explain Lamarck’s proposal that acquired traits
are passed onto their offspring.
(acquired trait: a trait that an organism develops in its lifetime;
c) Why were Lamarck’s hypotheses of evolution incorrect?
a) Lamarck said that structures that are used to
develop and are passed on to offspring (new
generations), whereas structures that are not used
are not passed on.
b) Lamark believed that acquired traits could be
passed onto offspring.
Some examples are:
- if a giraffe stretches its neck enough to reach
food during its lifetime, its neck will get longer.
Lamark believed the giraffe will pass on this long
neck trait to its offspring.
- if a human builds up very large muscles, from
weight lifting, it will pass on these large muscles
to its offspring
- if a crab uses one claw many times, then it will
increase the size of the claw. That crab’s
offspring will be born with large claws
c) Lamarck’s hypotheses of evolution were incorrect
because a single organism’s behaviour has no effect
on its heritable characteristics (traits that can be
passed on through sexual reproduction).
5) Distinguish between fitness and adaptation. Give an example of each.
Fitness, the ability of an individual to survive and
reproduce in its specific environment, occurs through
ongoing adaptation. An example is an animal that survives
through camouflage.
An adaptation is any inherited characteristics that
increases an organism’s chance of survival. Examples
include a porcupine’s quills, a lions teeth and claws.