Summative 4

Question 1

What are biotic factors? List some examples.

Answer 1

Biotic factors are all of the living organisms within an ecosystem.
Ex. Plants, animals, fungi

Question 2

Identify and describe three types of population dispersion patterns.

Answer 2

Clumped- pattern is clustered together
Uniform- pattern is spaced evenly
Random- individuals arranged without pattern

Question 3

Explain the differences between exponential growth models, logistical growth models, and boom and bust models.

Answer 3

Exponential Growth- Growth of a population with no limiting factors so the resources are unlimited.
Logistical Growth- Population growth slowed by limiting factors so there are limited resources.
Boom and Bust Cycle- Dramatic fluctuations in populations with an overall regularity.

Question 4

How do limiting factors affect a population’s carrying capacity?

Answer 4

Creatures have to compete for resources to survive

Question 5

Compare and contrast a population and a community.

Answer 5

Community- Groups individuals of different species found in an area.
Population- Groups individuals of a single species found in an area.

Question 6

What are interspecific interactions? Examples of +/+, +/-, and -/- interactions. What is commensalism?

Answer 6

Interspecific Interactions-Competition(-/-), Mutualism(+/+), Predation(+/-), Herbivory(+/-), Parasites and Pathogens(+/-), Commensalism(+/neutral)

Question 7

Define the following: Autotroph, heterotroph, carnivore, herbivore, and omnivore

Answer 7

Autotroph-Makes its own food
Heterotroph-Eats food made by other organisms
Carnivore-Eats meat products 
Herbivore-Eats plants and vegetation
Omnivore-Eats both plants and meat

Question 8

Explain the difference between photoautotroph and chemoautotroph

Answer 8

Photoautotroph-Produces food through photosynthesis.

Chemoautotroph-Obtains energy through oxidation of certain minerals.

Question 9

Explain biodiversity and how it is affected.

Answer 9

Biodiversity-The total number of all the different types of organisms living in an area. It can be affected by natural factors or by human factors.

Question 10

Define the following: consumer, producer, terrestrial ecosystem, aquatic ecosystem, detritivore, decomposer, aerobic, anaerobic

Answer 10

Consumer-An organism that obtains food by feeding on other organisms.
Producer-The first trophic level in a food chain which serves as a food source for consumers
Terrestrial Ecosystem-An ecosystem found only on landforms.
Aquatic Ecosystem-An ecosystem in a body of water.
Detritivore-An organism that derives energy from dead or decaying waste(detritus) through internal digestion.
Aerobic-Requiring oxygen.
Anaerobic-Not requiring oxygen.

Question 11

List the trophic levels in an ecosystem. How does energy flow through each level?

Answer 11

Levels: Producers, primary consumers, secondary consumers, tertiary consumers, quaternary consumers.
Energy Flow-The energy decreases 10% each time.

Question 12

Explain the difference between flow of matter and flow of energy in an ecosystem.

Answer 12

Energy Flow-How energy is transferred across the ecosystem.

Matter Flow-Like the flow of water, nitrogen, oxygen, phosphorus, carbon dioxide.

Question 13

Define the following: biosphere, atmosphere, hydrosphere, geosphere.

Answer 13

Biosphere-The regions of the surface, atmosphere, and hydrosphere of the earth occupied by living organisms.
Atmosphere-The envelope of gases surrounding the earth of another planet.
Hydrosphere-All the waters on the earth’s surface.
Geosphere-Any of the almost spherical concentric regions of matter that make up the earth and its atmosphere, as the lithosphere and hydrosphere.

Question 14

List the biogeochemical cycles in an ecosystem.

Answer 14

Water Cycle, Carbon Cycle, Nitrogen Cycle

Question 15

Sequence the steps of the carbon cycle in an ecosystem.

Answer 15

1. Carbon enters the atmosphere as carbon dioxide from respiration and combustion.
2. Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis.
3. Animals feed on the plant passing the carbon compounds along the food chain. Most of the carbon they consume is exhaled as carbon dioxide formed during respiration. The animals and plants eventually die.
4. The dead organisms are eaten by decomposers and the carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. 5. The plant and animal material may then be available as fossil fuel in the future for combustion.

Question 16

Differentiate between primary succession, secondary succession, and a climax community.

Answer 16

Primary Succession-An ecological succession that occurs following an opening an uninhabited, barren habitat or that occurs on an environment that is devoid of vegetation and usually lacking topsoil
Secondary Succession-The ecological succession that occurs on a preexisting soil after the primary succession has been disrupted or destroyed due to a disturbance that reduced the population of the initial inhabitants.
Climax Community-Expresses a biological community of plants, animals, and fungi which, through the process of ecological succession of the development of vegetation in an area over time, had reached a steady state.

Question 17

How do photosynthesis and cellular respiration contribute to the cycling of carbon?

Answer 17

Cellular respiration releases carbon dioxide, which is used in photosynthesis. Photosynthesis in turn releases oxygen used in respiration. Animals and other heterotrophs depend on green organisms for organic food, energy, and oxygen. In the carbon cycle, organisms exchange carbon dioxide with the atmosphere. On land, plants take up carbon dioxide via photosynthesis and incorporate it into food used by themselves and heterotrophs. When organisms respire, some of this carbon is returned to the atmosphere in the molecules of carbon dioxide. In aquatic ecosystems, carbon dioxide from air combines with water to give carbonic acid, which breaks down to bicarbonate ions. Bicarbonate ions are a source of carbon for algae. When aquatic organisms respire, they release carbon dioxide that becomes bicarbonate (HCO3). The amount of bicarbonate in water is in equilibrium with amount of carbon dioxide in air.

Question 18

What are abiotic factors? List some examples.

Answer 18

Abiotic factors are all of the nonliving things in an ecosystem.
Ex. Water depth, pH, sunlight