Download Natural Selection

8th Grade Science
Unit 5: Evolution – Genetics
Name: _______________________
Date: _________________
Natural Selection Review HW
Period: __________
Introduction: **Annotate 5 items in the margins. **
Darwin stated that evolution occurs through natural selection. They key factor is the
environment. The environment "selects" which organisms will survive and reproduce.
Traits possessed by organisms successful at survival and reproduction are more likely to
be passed on to the next generation. These traits will therefore become common.
Read the following information about the elephant population of Queen Elizabeth
National Park in Uganda, Africa and then fill out the table that follows.
Normally, nearly all African elephants, male and female, have tusks. In 1930, only 1% of
the elephant population in Queen Elizabeth National Park was tuskless because of a
rare genetic mutation. Food was very plentiful, organisms were very successful at
reproducing, and by 1963, there were 3500 elephants in the park. In the 1970s, a civil
war began in Uganda. Much of the wildlife was killed for food and poachers killed
elephants for their ivory tusks. By 1992 the elephant population dropped to about 200.
But, by 1998, the population had increased again to about 1200. A survey in 1998
revealed that as many as 30% of the adult elephants did not have tusks. Ugandan
wildlife officials also noted a decline in poaching.
Use the information above to fill out the chart. In the left column, write the 4 components
of Darwin's theory of natural selection. In the right column, name an example of each
point from the paragraph above.
Component of natural selection
Example within elephant population
Natural Selection “Quiz”
Part 1: Multiple Choice
Circle the letter of the statement that best answers each question.
1. According to Darwin, evolution occurs:
a. by chance
b. to only certain organisms
c. by inheriting acquired characteristics
d. by natural selection
2. The traits of individuals best adapted to their environment become more
common in each new generation because:
a. offspring without those traits do not survive
b. the genes responsible for those traits increase through natural selection
c. those individuals inbreed
d. natural selection does not affect well-adapted individuals
3. Natural selection causes:
a. changes in the environment
b. plants and animals to produce more offspring than can survive
c. changes i nthe physical characteristics of a population
d. all of the above
4. The theory of evolution predicts that:
a. closely related species will show similarities in their DNA sequences
b. if species change over time, their genes will also change
c. closely related species will show similarities in amino acid sequences
d. all of the above
Part 2: True or False
Write T if the statement is true and F if the statement is false
______ 5. Darwin suggested that species change over time through the use and
disuse of physical traits.
______ 6. A species is a group of organisms that mate and produce fertile
offspring.
______ 7. Darwin came up with the theory of natural selection completely on his
own through observations that he made during his voyage around the world on
the HMS Beagle.
______ 8. The change in species over time is called evolution.