Chapter 3 Test Flashcards
Why do ecologists ask questions about events and organisms that range in complexity from an individual to the biosphere?
To understand relationships in the biosphere.
What are the levels of organisation?
Species, Populations, Community, Ecosystem, and Biome.
What is the highest level that ecologists study?
The entire biosphere.
What are three basic approaches scientists use to conduct modern ecological research?
Observing, experimenting, and modeling
Why would an ecologist set up an artificial environment in a laboratory?
To imitate and manipulate conditions that organisms would encounter in the natural world.
Can an ecological model consist of a mathematical formula?
Yes.
What is at the core of every organisms’s interaction with the environment?
The need for energy.
What source of energy do organisms use that don’t use the sun’s energy?
Inorganic compounds.
What are autotrophs?
Organisms that use energy from sunlight to make food.
What do autotrophs do during photosynthesis?
They use light energy to convert carbon dioxide and water into oxygen and starches.
What is chemosynthesis?
When organisms use chemical energy to make carbohydrates.
Where do bacteria that carry out chemosynthesis live?
In very remote places, like volcanic vents and hot springs.
What are heterotrophs also called?
Consumers.
What is a herbivore?
A consumer that eats only plants.
What are examples of herbivores?
Cows and rabbits.
What is a carnivore?
A consumer that eats animals.
What are some examples of carnivores?
Snakes, dogs, and owls.
What are omnivores?
Consumers that eat both plants and animals.
What are some examples of omnivores?
Humans, bears, and crows.
What is a detritivore?
A consumer that eats dead matter.
What are examples of detritivores?
Mites, earthworms, snails, and crabs.
What are decomposers?
Organisms that break down organic matter.
What are examples of decomposers?
Bacteria and fungi.
How does energy flow through an ecosystem?
From the sun to autotrophs to heterotrophs.
What is a food chain?
A series of steps in which organisms transfer energy by eating and being eaten.
What is a food web?
A network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem.
What does a food web link together?
All the food chains in an ecosystem.
What is a trophic level?
Each step in a food chain or web.
What always makes up the first trophic level in a food web?
Producers.
What does a consumer in a food chain depend on for energy?
The trophic level below it.
Why is only part of the energy in one trophic level passed on to the next level?
Organisms use much of the energy they consume.
What is biomass?
The total amount of living tissue in a trophic level.
What does a biomass pyramid represent?
The amount of potential food available in that level.
Why can each trophic level support only about one tenth the amount of living tissue as the level below it?
Each trophic level harvests one tenth of the energy of the level below it.
What are the four elements that make up 95% of the body?
Oxygen, carbon, hydrogen and nitrogen.
How does matter move through an ecosystem?
In biogeochemical cycles.
What do biogeochemical cycles connect through?
The biological, geological, and chemical aspects of the biosphere.
How can water enter the atmosphere?
Evaporating from the leaves of plants in the process of transpiration.
What are the three processes involved in the water cycle?
Precipitation, evaporation, and run-off.
What is a nutrient?
All the chemical substances that an organism requires to live.
What are the three nutrient cycles that play an important role in the biosphere?
Carbon cycle, nitrogen cycle, and phosphorous cycle.
What are the four processes in the carbon cycle?
Biological process, geochemical process, mixed geochemical process, and human activity.
Where is carbon found?
- as carbon dioxide in the atmosphere
- as dissolved carbon dioxide in the ocean
- as coal and petroleum underground
What is nitrogen fixation?
The process by which bacteria converts nitrogen into ammonia.
What is denitrification?
The process by which soil bacteria convert nitrates into carbon gas.
Why is phosphorous essential to living things?
It forms parts of molecules like DNA and RNA.
What is the primary productivity of an ecosystem?
The rate at which organic matter is created by producers.
What is a limiting nutrient?
When the ecosystem is limited by a single nutrient.
Where is nitrogen often the limiting factor?
The ocean.
Where is phosphorous the limiting factor?
Streams, lakes, and freshwater.
When do blooms occur?
When there are more nutrients available (the producers can grow and reproduce more quickly)
What is the scientific study of interactions among organisms and between organisms and their surroundings?
Ecology
