Unit 8 (EOC/SMA)

Which substance do biochemists often search for in fossils to help better understand the evolutionary relationships of the organism that formed the fossil? (3.4.1)

• ATP
• DNA
• iron
• oxygen

Some marine worms and mollusks go through similar larval stages during development. Which can be inferred about their relationship? (3.4.1)

• They share a common ancestor.
• They mate with each other.
• They compete for a habitat.
• They share the same food source.

Scientists believe that the polar bear in Alaska and the brown bear in Russia evolved from a common ancestor. Which would be responsible for this evolutionary change? (3.4.2)

• artificial selection
• asexual reproduction
• sexual competition
• geographic isolation

Which statement best describes natural selection? (3.4.2)

• As the weather changes, organisms that are able to find shelter need less energy to live.
• Organisms that eat only plants need less food than organisms that eat animals.
• Organisms better adapted to their environment are more likely to reproduce and pass on their traits to their offspring.
• Small organisms are more likely to survive than larger organisms.

An antibiotic which was effective 20 years ago against a specific type of bacterial infection no longer works against the same kind of infection today. Which best explains why the antibiotic is no longer as effective as it was 20 years ago? (3.4.3)

• Bacteria resistant to the antibiotic have killed off nonresistant bacteria.
• Viruses have changed the structure of the bacteria that causes the infection.
• Resistant bacteria have survived and reproduced at a greater rate than nonresistant bacteria.
• The human body has developed an immunity to the antibiotics.

An insecticide kills most of the ants on a plant. Over time, it is determined that the insecticide is not as effective for killing ants. Which statement best explains this observation? (3.4.3)

• The ants killed initially by the insecticide were genetically the same as the surviving ants.
• The ants killed initially by the insecticide had thinner cell membranes than the surviving ants.
• The ants that survived were younger than those that died as a result of the insecticide.
• The ants killed by the insecticide and the surviving ants were genetically different.

How does natural selection explain why some organisms are more likely to survive and reproduce than other organisms?

• Some organisms inherit traits enabling them to adapt better to the environment
• Some organisms acquire traits during their lifetimes that they pass to their offspring
• Some organisms do not reproduce as many offspring during their lifetimes
• Some organisms die before they reproduce any offspring

Which characteristics of an insect population enable it to adapt and develop resistance to a pesticide more quickly?

• greater variation and high rate of reproduction
• less variation and slow rate of reproduction
• greater variation and slow rate of reproduction
• less variation and high rate of reproduction

If a farmer routinely sprays his crop of lettuce with the same pesticide, what will be the outcome of his pesticide use over time?

• He will never have any insects eating his crop of lettuce because the continued use of the pesticide will kill all of them
• Over time, the pesticide that the farmer is spraying on the lettuce will build up in the plants, killing most of his crop
• Some insects will be resistant to the pesticide, and over time, they will become more abundant, eating more of his crop
• Some insects will die immediately from the pesticide, and the rest will die over a period of months as the pesticide builds up in their systems

DDT was once used throughout the world as an insecticide to kill mosquitoes. Its regular use initially brought down the mosquito count but later resulted in a population of mosquitoes that was resistant to DDT. Which reason best explains the ineffectiveness of DDT in controlling the mosquito population?

• Mosquitoes evolved biochemical mechanisms in their bodies to make DDT ineffective
• Mosquitoes that were naturally resistant to DDT lived and produced resistant offspring
• Mosquitoes mutated which made them resistant to DDT
• Mosquitoes adapted to the presence of DDT in the environment