Ecology: Chapter 3

Question 0

Biosphere

Answer 0

part of the earth where life exists; extends from about 8 km above the earth’s surface and 11 km below the surface of the ocean

Question 1

Ecology

Answer 1

the study of interactions of organisms with one another and their physical environment

Question 2

Biological Species

Answer 2

All organisms of one kind that are so similar to one another that they can produce fertile and viable offspring

Question 3

Population

Answer 3

Groups of individuals that belong to the same species and live in the same area

Question 4

Community

Answer 4

Assemblages of different populations that live together in a defined area

Question 5

Energy Flow

Answer 5

• every action of every organism requires energy
• the amount of energy available is the single most important factor in determining how many and what kinds of organisms live in an ecosystem
• the main energy source for life on earth is the sun
• less than 1% of this energy is actually used by living things

Question 6

(Primary) Autotrophs or Producers

Answer 6

Organisms that make their own food (complex organic molecules) using inorganic raw materials in their environment; these organic molecules are used to synthesize living tissue
- example: some prokaryotes, specifically the Cyanobacteria; all algae; all plants

Question 7

Autotrophs or Producers

Answer 7

• Most of these organisms use sunlight as their energy source and make their own food by a process called photosynthesis
• others rely on the energy stored in inorganic chemical compounds (hydrogen sulfide) to produce their own food, this is a process known as chemosynthesis
• example: certain bacteria living in hot springs or undersea vents (hostile environments)

Question 8

Consumers or Heterotrophs

Answer 8

Organisms that cannot make their own food and therefore must rely on other organisms for their energy and food supply
-example: many Protists and bacteria (both unicellular, simple multicellular); all animals and all fungi

Question 9

Herbivores

Answer 9

Obtain their energy by eating only plants/producers

-example: cow, grasshoppers, lady bug, deer, gorilla

Question 10

Carnivores

Answer 10

Obtain their energy by eating animals/consumers

-examples: praying mantis, dragonflies, frog, centipede, shark

Question 11

Omnivores

Answer 11

Obtain their energy by eating both producers and consumers

-example: Bears, skunk, possums, raccoon, humans

Question 12

Detritivores

Answer 12

Feed on animal and plant remains and other dead matter (collectively referred to as detritus); also called saprobes or reducers; all are consumers
-example: mites, earthworms, snails, and crabs

Question 13

Decomposers

Answer 13

A specific type of detritivores; microscopic organisms that break down and absorb organic matter (found in wastes and dead organisms)
-example: bacteria and fungi of decay

Question 14

Scavengers

Answer 14

Organisms that feed on larger remains of dead organisms

-example: vultures and hyenas

Question 15

Feeding Relationships

Answer 15

• energy flows through ecosystems in one direction from the sun or inorganic compounds (the two main forms of energy that power living systems)- first to producers and then to various consumers

Question 16

Food chains

Answer 16

A series of steps in which organisms transfer energy by eating being eaten
-the first link (the base) is always a producer; the arrow always points to the eater

Question 17

Plankton

Answer 17

Tiny free floating or weakly swimming microorganisms that occur in aquatic environments

Question 18

Phytoplankton

Answer 18

Plankton that photosynthesizes; algae

Question 19

Zooplankton

Answer 19

Heterotrophic plankton; include larvae (immature forms) of many organisms

Question 20

Primary or first order consumers

Answer 20

Those that feed upon producers; all herbivores; the second link in any food chain

Question 21

Secondary or second order consumers

Answer 21

Those that feed upon first order consumers; carnivores, though some may be omnivorous

Question 23

Notes regarding food chains

Answer 23

• the first link is always some kind of producer
• first trophic level: producer
• second trophic level and above: consumer
• each consumer depends on the trophic level below it for food and energy

Question 24

Food Webs

Answer 24

network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem. each food web links all food chains of an ecosystem together

Question 25

Pyramid of Energy

Answer 25

- as we move from one trophic level to the next, 90% of the energy is lost - at each trophic level, the energy stored in the organisms is about 10% that of the level below it

Question 26

What happens to the energy that is passed on?

Answer 26

- It's used to build tissue and as an energy source - The more levels that exist between a producer and a top level consumer, the less energy that remains from the original amount. As a result, organisms at higher trophic levels usually tend to be lower in number than those at the lower trophic levels

Question 27

Pyramid of Biomass

Answer 27

represents the amount of potential food available for each trophic level in an ecosystem

Question 28

Biomass

Answer 28

- the total amount of living tissue within any given trophic level or ecosystem - usually expressed as organic matter / unit area

Question 29

What agent powers the water cycle?

Answer 29

the sun

Question 30

Transpiration

Answer 30

the evaporation of water through a plants leaves

Question 31

Evaporation

Answer 31

liquid to gas; have to heat it up

Question 32

Condensation

Answer 32

gas to liquid; gets colder

Question 33

Precipitation

Answer 33

condensation around dirt particles --> falls to the earth

Question 34

Carbon Cycle

Answer 34

- less than 1% of all the carbon on earth actually cycles in the biosphere - less than 1% of the atmosphere is CO2 gas - carbon is the key ingredient in all organic compounds - green houe effect: retention of the sun's heat; resulting in global warming

Question 35

Nitrogen Cycle

Answer 35

- the form of nitrogen plants use: ammonia/ammonium or nitrates - once the nitrogen is in the organism's cells, it must assimilate it or ultilize it - nucleotides, ATP, amino acids, proteins - 79% of our atmosphere is nitrogen

Question 36

Nitrogen Fixation

Answer 36

N2 --> NH3/NH4+

Question 37

Ammonification

Answer 37

Nitrogen compounds in dead organisms --> NH3/NH4+

Question 38

Nitrification

Answer 38

NH3/NH4+ --> NO2- --> NO3-

Question 39

Dentrification

Answer 39

NO3- --> N2

Question 40

Phosphorus Cycle

Answer 40

- does not enter the atmosphere - mainly found in rock/soul and ocean sediments as inorganic phosphate - plants take it in from the soil / algae take in in from the water

Question 41

How to consumers get their phosphorus?

Answer 41

By eating

Question 42

Primary productivity

Answer 42

the rate at which organic matter is created by producers

Question 43

Limiting Nutrient

Answer 43

-single nutrient that is either scarce or cycles very slowly, limiting the growth of organisms in an ecosystem

Question 44

Key Limiting Nutrients

Answer 44

a) in the soil: Nitrogen, Phosphorus, and Potassium (the three key minerals listed on fertilizer packages) b) in oceans: nitrogen, silica, or iron c) in fresh-water environments: phosphorus

Question 45

Eutrophication

Answer 45

an ecosystem's response to the addition of artificial or natural substances such as nitrates or phosphates, to an aquatic ecosystem

Question 46

Oligotrophic

Answer 46

having few nutrients

Question 47

Algal Bloom

Answer 47

an unnatural population growth of algae or cyanobacteria