8th Grade Science Review

According to most scientists, what is the ultimate cause of most mass extinctions?

• overhunting

• evolution of new species to replace old ones

• major change in environment due to extreme natural events

• asteroid impact

Which of these describes a species that has become extinct?

• fewer members of the species are dying than being born
• more members of the species are dying than being born
• very few members of a species are alive
• all members of a species have died

Which of the following species is extinct?

• woolly mammoth
• giant panda
• bald eagle
• green sea turtle

Which of the following is NOT a reason a species may become extinct?

• competition
• reproducing
• habitat loss
• overhunting

What to carnivores eat?

• Meat

• Plants

• Plants & Meat

Species that are in danger of becoming extinct are called __________.

• endangered

• not lucky

• extinct

• in a jam

What would most likely happen if a bird species had fewer and fewer offspring each year?

• The species would move to another ecosystem.
• There would be too many birds.
• The species would become endangered.
• Predators of the species would increase in number.

What % of the species that have every lived are alive today?

• 1%

• 10%

• 50%

• 75%

1. The process of choosing parent organisms for desired characteristics is called

• natural selection

• Artificial selection

• random selection

• genetic manipulation

Which statement is true comparing natural selection and artificial selection?

• In natural selection, traits benefit humans and in artificial selection, the traits benefit the species

• In natural selection, traits benefit the species and in artificial selection, the traits benefit humans

• In natural and artificial selection, the process takes hundreds of years to occur

• In natural and artificial selection, nature determines what traits will be passed down to offspring.