Answers to exploration questions: biodiversity distribution patterns

If you are wondering where the suggested answers came from, you can review the videos and articles in the biodiversity distribution patterns tutorial.

1. In your own words, define what the term “biomass” means. Explain how you would calculate the biomass in a given area.

Answer: A complete explanation would mention that biomass is the weight – or mass – of all the organisms in a given area. To calculate biomass, you would need to know the different types of organisms that live in the area, the number of individuals in each of the species, and the weight of each of those organisms. Since it is usually impossible to weigh every individual, scientists frequently use an average weight for individuals of the different species. If you could count up all the organisms in a redwood forest and weigh them, for example, you would be calculating the biomass of that forest.

2. After watching the two examples of road trips in the video of how biodiversity is distributed globally, explain how the Arctic tundra and the Amazon rainforest differ in terms of species richness and populations. How are they similar?

Answer: A complete explanation would mention that the Arctic tundra has many fewer species than the Amazon rainforest, but the population size of each tundra species can be very large. In the Amazon rainforest, the species richness is much greater – so great that it would be hard to calculate; but the size of each species’ population may not be very large. The two are the same in that both areas have a lot of life.

3. Your friend comments that organisms cannot live and thrive in extremely cold or extremely hot environments. Explain in a few sentences why you agree or disagree with your friend’s statement.

Answer: While everyone is entitled to their own opinion, scientists would not agree with your friend’s statement. There are several places that are very extreme environments in which you find life, such as underneath a couple miles of ice in Lake Vostok in Antarctica or in hot thermal pools in Yellowstone with temperatures close to boiling. Microbes such as bacteria have amazing adaptations for living in these extreme environments.

4. Consider the following statement: Humans have changed the ranges of many organisms. Do you agree or disagree? Explain why and give a few examples.

Answer: Agree. A complete explanation would mention that humans have affected the ranges of many species over centuries. Humans have expanded the ranges of some organisms by taking them to new areas where they can be used for transportation or food, such as cattle and corn. They have also transported organisms to new areas accidently such as has happened with aquatic species found in the ballast water of ships. Also, as cities, roads and dams are built, habitat can become fragmented or changed, restricting or eliminating the ranges of organisms that live there.

5. Why do humpback whales and whale lice have the same ranges? What type of range factor does this represent? Explain your answer in a few sentences.

Answer: A complete explanation would mention that the lice are parasites and live on the whale. Anywhere the whale travels, the lice go there too, so the ranges of these two species are identical. This is an example of a biotic factor that determines the range of the whale lice.