Download S7L4d Relationships Study Guide Answer Key

S7L4d. Relationships Study Guide Answer Key
1. What is competition? The struggle between organisms that attempt to use the same limited resources.
Organisms that are better at competing are more likely to get and use the available resources.
2. What is predation? Predation is an interaction in which one organism captures and feeds on another
organism for food. The organism that does the killing is called the predator, and the organism that is
eaten is the prey.
3. What traits do predators and prey have that make them good at what they need to do? Predators have
traits that enhance their ability to capture prey, such as fast speed, keen eyesight, or sharp teeth. Prey
have traits that help keep them avoid being captured. These might include the ability to escape
quickly or hide in their environment.
4. Describe the pattern of predator and prey relationships over time (think about the wolf lab!). At some
point, the prey population grows so large that the prey are easy to find. In turn the predator
population grows because predators have a good supply of food. As the predator population grows,
they continue to feed on prey. This causes prey population to decrease. As the food supply decreases,
the large population of predators can no longer be supported. The predator population then
decreases. With a smaller number of predators, the prey population can grow and the cycle repeats.
5. Draw a graph of the predator-prey relationship!
6. What is symbiosis? A close relationship that benefits at least one of the species. There are three types
of symbiotic relationships – mutualism, commensalism, and parasitism.
7. What is mutualism? Give an example. Both species benefit. Bees and flowers –bees feed on the nectar
produced in flowers. As they feed, pollen in the flower sticks to the bees. When a bee moves on to feed
at another flower, some pollen is carried with it so that the flowers can reproduce. Bees benefit by
having food, flowers benefit by reproducing. Sea anemones and clownfish are another example.
8. What is commensalism? Give an example. A relationship in which one species benefits, and the other
species is neither helped nor harmed by the relationship. Barnacles and whales – barnacles attach
themselves to the whales, and they benefit because they have a place to live and a method of
transportation, and the whale is neither helped nor harmed.
9. What is parasitism? Give an example. A relationship in which one organism lives on or inside another.
The organism that benefits is called the parasite, and the organism that it lives on or in, and is
harmed, is called the host. Tapeworms and humans are an example of parasitism – the tapeworm is
the host, and the human is the host.
10. Describe the relationship between scientists and the environment. When studying the environment,
scientists should try and disturb as little as possible. They should avoid harming organisms, and do
as much observation as possible.