Core Case Study Question 1

CHAPTER 3: CHAPTER REVIEW

Core Case Study Question 1:

What are three harmful effects resulting from the clearing and degradation of tropical rain forests?

*reduce the earth's vital biodiversity by destroying or degrading the habitats of many of the unique plant and

animal species that live in them
*accelerate atmospheric warming, and thus impacting climate change...fewer trees means less CO2 removed

during photosynthesis...therefore...more CO2 (main greenhouse gas) in atmosphere
*can change regional weather patterns in ways that can prevent the return of diverse tropical rain forests...

trees influence rainfall...plants release water (transpiration)...creating precipitation...fewer trees

means less water released to atmosphere...results in less rain...drier climate

Critical Thinking Question 1:

How would you explain the importance of tropical rain forests to people who think that such forests have no connection to their lives?

Nature’s laboratory...many diverse species
Most diverse plant & animal species in the world...potential medicines, medical cures, homes for wildlife
Maintain climate...remove CO2 to reduce effects of global warming
Slow soil erosion...trees prevent erosion...rainforest soil is low in nutrients...so it’s important that erosion be controlled

Critical Thinking Question 2:

Explain why –(a) the flow of energy through the biosphere depends on the cycling of nutrients and – (b) the cycling of nutrients depends on gravity.

(a)Plants convert solar energy into chemical energy that is stored in carbon compounds during photosynthesis. In order to do this, plants require CO2 and H2O. Plants also use nitrogen compounds and phosphorus from the soil. Energy is passed from plants to consumers through the food chain. Eventually plants and animals die and decay during the process of decomposition, which returns CO2, H2O, and nitrates back to the soil. At this stage, the last of the energy is extracted (and lost as heat) and the inorganic nutrients are returned to the soil or water to be taken up again. Therefore, this cycle of nutrients and energy flow is important for all life forms to exist in biosphere. Inorganic nutrients are either taken up by plants from atmosphere or water. For taking up nutrients from water, water cycle is necessary. The carbon cycle involves carbon dioxide and the nitrogen cycle involves nitrates.h

(b)The cycling of nutrients in the environment depends on gravity because nutrients must at some point filter down through the soil into waterborne functions so that they may be absorbed by root systems of plants which make up the base of a nutrient cycle. Gravity is what holds the gases and compounds within the Earth’s atmosphere & biosphere so they can be recycled and not lost.

Critical Thinking Question 3:

Explain the importance of microbes.

Microbes help in many ways:
*bacteria in our intestinal track break down food we eat
-*help prevent harmful bacteria from reaching our lungs
*help purify water
*help produce bread cheese, yogurt, soy sauce, beer and wine
*decompose waste into nutrients

*control populations of species of insects that attack our food crops

*control diseases

2 benefits on our health:

Help digest food

Help prevent harmful bacteria from reaching our lungs

Help purify water

2 harmful effects on health

Make us sick

Cause food poisoning

What would happen to us if there were no more microbes

The planet's oceans and soils would enter into a period of stagnation owing to the complete loss of biogeochemistry. Worse, without bacteria to play a role in the nitrogen fixation process, most global photosynthesis would come to a grinding halt within a year. At the same time, there would be no microbes to break down massive amounts of accumulating waste. The biomass would accumulate, "creating vast reservoirs of biogeochemical waste that no biological entity could transform, at least initially." It would mark the end of biogeochemical recycling — a process on which all life depends. We would not be able to break down and digest food properly.

Critical Thinking Question 7:

What would happen to an ecosystem if (a) all of its decomposers and detritus feeders were eliminated. (b) all of its producers were eliminated and (c) all of its insects were eliminated? (d)Could a balanced ecosystem exist with only producers and decomposers and no consumers such as humans and other animals. Explain.

(a)The ecosystem would not be able to recycle matter and wastes would build up. Eventually other species would die as no nutrients would be released for plant growth

(b)Producers are the base of the food chain...so if they die...so would herbivores and eventually carnivores...there would be no energy produced to sustain these other trophic levels so the ecosystem would collapse.

(c)Insects play a crucial role in plant pollination...so if all insects were eliminated...eventually plants will die. This scenario would ultimately impact 2 key concepts of sustainability: cycling of nutrients and energy flow...the ecosystem therefore could not be sustained

(d)A balanced ecosystem could not exist without consumers. While producers are the base of the food chain...without consumers...there would be no flow of energy or cycling of nutrients (2 vital factors in sustainability). Decomposers would not have that much to decompose without a variety of species. A balanced ecosystem requires diversity and various types of animals and different system checks in order to keep itself balanced and organized

DATA ANALYSIS problem

Approximate NPP of tropical rainforest:8800 kcal/m2/yr

Terrestrial ecosystem that produces 1/3 this rate:savanna

8800/3 = 2933

Aquatic ecosystem about the same as rainforestestuaries

Early in the twentieth century, large areas of temperate forest in the eastern U.S. were cleared to make way for farmland. For each unit of this forest area that was cleared and replaced by agriculture, how much NPP was lost? (Assume that the average NPP of temperate forest is 5,800 kcal/m2/yr and the average NPP of agricultural land is 2,800 kcal/m2/yr.) 3000 kcal/m2/yr
Deserts & grasslands lower NPP than swamps & marshes:little water; warmer temps: limit

rate of photosynthesis & productivity

How much more NPP do estuaries produce compared about 4 times more

to lakes & streams?

(NPP estuaries: 9000 kcal/mw/yr; lakes/streams: 2100 kcal/m2/yr)

This is because estuaries are more complex, have a high degree of nutrients from runoff, streams and

from the ocean/salt water mixing in them in comparison to lakes and streams. These nutrient rich

waters are better able to support more producers and therefore tend to have higher NPP.

MULTIPLE CHOICE

1. a

2. a

3. e
4. e
5. d
6. c
7. d
8. b
9. c

10. a
11. e
12. B

CHAPTER 4 CHAPTER REVIEW

Core Case Study Question 1

Describe the threats to many of the world’s amphibian species and explain why we should avoid hastening the extinction of any amphibian species through our activities

A decrease in population of species and even extinction.
They are biological indicators of changes to the environment( habitat loss, air and water pollution)
Adult amphibians play important ecological roles in biological communities [Example: extinction of one species could lead to extinction of other species such as those who feed on frogs]
Amphibians are a genetic storehouse of pharmaceutical products [Example: skin from certain amphibians can be used for painkillers and antibiotic]

Critical Thinking Question 1

How might we and other species be affected if all amphibians were to go extinct?

frogs consume mosquitos & other insects.Mosquitos are known to create untold misery to variety of animals on Earth.Their numbers will increase,adding to the misery & in absence of frogs,numbers of other predators like calotes & birds would increase.If frog's are not there,a number on snakes living on them also would become extinct.These snakes form the food of other predatory birds & bigger snakes,so their numbers would drastically decrease & could also become extinct. Juveniles of predatory fishes,some of them, consume tadpoles & in their absence,they would have to foray in search of alternative food,which can expose them to natural predators,bringing down their population,

Critical Thinking Question

Multiple Choice

2. d
3. c
4. c
6. a
7. b
8. b
9. d
11. d
4,000 lbs = 3ppb * x
x = 1.33*10^12lbs of water
1.33*10^12 lbs * 1gal/8.34 lbs =1.60 * 10^11 gal
12. e
13. A

CHAPTER 5 CHAPTER REVIEW

Core Case Study Question 1

Explain how southern sea otters act as a keystone species in their environment. Explain why we should care about protecting this species from extinction that could result primarily from human activities

Sea otters prey on the sea urchins, which helps the kelp forests. The sea otters keep the population of sea urchins down, which allows the kelp forests to grow, & helps keeps kelp forests from being destroyed. we need kelp forests because they provide biodiversity.

sea otters should be protected is because they are a creature that everyone loves, which generates millions of dollars a year from tourism in the coastal areas where the sea otters are found.
- because it is ethical, many people believe it is wrong to cause premature extinction on a species.
- because they are a keystone species, and without the sea otter, the kelp forests would most likely be destroyed. We need kelp forests because biodiversity is extremely important to the earth's natural capital

Critical Thinking Question 1

What difference would it make if the southern sea otter became extinct primarily because of human activities? What are three things we could do to help prevent the extinction of this species?

The extinction of the sea otter would cause dramatic change in our ocean ecosystems as the sea otter acts as a keystone species controlling the sea urchin population that would otherwise decimate the highly productive kelp forests. Activities that might help prevent the demise of the species is to join an organization that works on their behalf, Support efforts to reduce the hunting and poaching of sea otters, and support efforts to educate the public on how to appreciate the species.

Critical Thinking Question 3

How would you reply to someone who argues that we should not worry about the effects that human activities have on natural systems because ecological succession will heal the wounds of such activities and restore the balance of nature

Succession may be able to restore the balance of nature and heal some of the wounds that humans have inflicted, however succession takes place over hundreds or thousands of years and will not be able to take place at a fast enough rate to restore the imbalances that humans are causing in the short term. We do need to worry about human effects on natural systems.

Multiple Choice

a
2. d
3. e
4. b
5. e
6. d
7. e
8. d
9. d
10. e
11. c
12. c
13. C

FRQ...

(A) Describe TWO characteristics shared by ecosystems that have high biodiversity.

1) Large number of different species
2) Large number of individuals of different species

(B) Identify TWO specific human activities that result in a loss of biodiversity and explain
how each activity lowers biodiversity.

1) Clearing land for construction- Reduces habitat for many species
2) Burning of fossil fuels- Death of coral reefs

(C) For each human activity you discussed in (b), propose a practical strategy (other than
simply banning the activity) to reduce the loss of biodiversity.

1) Clearing land for construction- Cluster development
2) Burning of fossil fuels- Carbon tax

(D) Describe ONE naturally occurring factor that could lead to a loss of biodiversity.

1) Droughts (e.g., food source may be lost)

(E) Describe TWO ecological benefits that greater biodiversity provides.

1 Pollination
2) Control of pest species