Environmental Change

Scientists fear that the burning of fossil fuels by humans will disrupt the stability of ecosystems around the world. One of the main concerns regards the production of greenhouse gases which are known to -

• decrease the rate of photosynthesis

• emit harmful gamma radiation

• trap heat in the lower atmosphere

• poison the terrestrial biota

Populations of Caribbean coral have decreased significantly over the past 30 years due to disease. Which of the following is most likely a major factor leading to the increased amount of disease in the coral?

• Symbiotic algae are living in the coral cells.

• Several different species of fish live on the coral reefs.

• Levels of spawning have decreased and lowered reproductive rates.

• Water temperatures have increased and favored the growth of microorganisms.

Which of the following human activities is most likely to cause the greatest disruption to the environment?

• Replanting felled trees

• Burning fossil fuels

• Recycling cardboard boxes

• Capturing solar energy

Humans have been using increasing amounts of land to build houses and construct roadways. Which statement below describes how this expansion affects organisms from these areas?

• Species are quickly adapting to new habitats and different niches

• The loss of habitat is reducing the population size of other animals

• Carnivores are being forced to eat vegetation in lieu of meat

• Animals are developing new habits that complement human life

Global warming could cause the polar ice caps to melt increasing the amount of fresh water in the ocean and disrupting the flow of natural currents that cycle heat around the world. This change would most likely result in which of the following?

• An increase in climate change

• The collision of tectonic plates

• An increase in producer populations

• The reduction of ocean sediments

Deforestation has which of the following effects on the biomass and biodiversity of the plant and animal community in these ecosystems?

• biomass and biodiversity both increase

• biomass and biodiversity both decrease

• biomass increases but biodiversity decreases

• biomass decreases but biodiversity increases

Which of the following scenarios would have the most severe effect on a pond ecosystem?

• Allowing animals to drink the water

• Preventing fertilizers from entering the water

• Having a prolonged regional drought

• Limiting the use of the pond for fishing

Human activities release compounds into the environment which lower the pH of the surrounding soil and water supplies. This change to the ecosystem can cause a reduction in the producer populations and have a negative effect on all aquatic life. Which of the following contributes the most to these effects?

• Constructing water treatment plants that efficiently remove pollution and conserve water

• A reduction in the use of fossil fuels in favor of alternate, renewable energy sources

• Farming practices that reduce the use of fertilizers in favor of organic farming techniques

• Precipitation carrying these pollutants from the atmosphere to the ground and water supply

The use of fertilizers on farmland can eventually cause an overgrowth of algae to appear in surrounding aquatic ecosystems. What process contributes to the eutrophication of these water sources and the increased growth of algae?

• A decreased use of water by animals

• An increase in runoff after heavy rains

• An increase in the sedimentation of rivers

• A decrease in the erosion of creek beds

A large number of woodland animal populations are much smaller than they were 100 years ago. One of the primary reasons these populations have been reduced is –

• the loss of habitats

• the use of fertilizers

• a decline in poaching

• an increase in offshore drilling