Ecosystems (Unit 3 Topic 2)

Question 1

Define Producers

Answer 1

Producers are organisms that make their own organic nutrients (food) - usually using energy from sunlight. Green plants make their food by photosynthesis

Question 2

Define Consumers

Answer 2

any organism that can’t make its own food. Consumers have to feed on producers or other consumers to survive. Deer are herbivores, which means that they only eat plants (Producers).

Question 3

Define Ecological Pyramids

Answer 3

Ecological pyramid is a graphical representation in the form of a pyramid showing the feeding relationship of groups of organisms. It also shows the flow of energy or biomass at each trophic level in a particular ecosystem.

Question 4

Define Detritus

Answer 4

matter composed of leaves and other plant parts, animal remains, waste products, and other organic debris that falls onto the soil or into bodies of water from surrounding terrestrial communities.

Question 5

Define Decomposer

Answer 5

organism that breaks down dead organic material; also sometimes referred to as detritivores.

Question 6

What is Gross Primary Productivity?

Answer 6

is the amount of carbon fixed during photosynthesis by all producers in the ecosystem. However, a large part of the harnessed energy is used up by the metabolic processes of the producers (respiration).

Question 7

What is Net Primary Productivity?

Answer 7

how much carbon dioxide vegetation takes in during photosynthesis minus how much carbon dioxide the plants release during respiration (metabolizing sugars and starches for energy).

Question 8

Define Random Sampling

Answer 8

used to select a sample that is unbiased. Within each area, every part of the area must have an equal chance of being chosen. Random sampling with quadrats is used to examine differences between contrasting habitats within an habitat.

Question 9

Define Zonation

Answer 9

the division of an ecosystem into distinct zones / bands / regions / in horizontal layering due to an environmental gradient (abiotic conditions).

Question 10

Define Stratification

Answer 10

the vertical layering of a habitat; the arrangement of vegetation in layers, largely according to the different heights to which their plants grow.

Question 11

Define foliage cover

Answer 11

% of ground surface covered by vegetation or other coverages

Question 12

Define Quadrat

Answer 12

usually a square made of wire. It may contain further wires to mark off smaller areas inside, such as 5 × 5 squares or 10 × 10 squares. The organisms underneath, usually plants, can be identified and counted. Quadrats may also be used for slow-moving animals, eg slugs and snails.

Question 13

Define Transect

Answer 13

is a line across a habitat or part of a habitat. It can be as simple as a string or rope placed in a line on the ground. The number of organisms of each species along a transect can be observed and recorded at regular intervals.

Question 14

What is a Belt Transect?

Answer 14

A strip, typically 1 m wide in herbaceous vegetation, that is marked out across a habitat and within which species are recorded to determine their distribution in the habitat.

Question 15

Define Strip Census

Answer 15

an estimate of the numbers of a wild animal in an area by counting individuals along a typical strip and assuming a uniform population.

Question 16

What is the Capture - Recapture method?

Answer 16

used to estimate the size of a population where it is impractical to count every individual. The basic idea is that you capture a small number of individuals, put a harmless mark on them, and release them back into the population.

Question 17

What is the Lincoln Index (N)?

Answer 17

provides a way to measure population sizes of individual animal species. It is based on a capture /mark / recapture method.

Question 18

Define biogeochemical cycles

Answer 18

is the pathway by which a chemical substance cycles the biotic and the abiotic compartments of Earth.

Question 19

Define Nutrient Cycles

Answer 19

repeated pathway of a particular nutrient or element from the environment through one or more organisms and back to the environment. Examples include the carbon cycle, the nitrogen cycle and the phosphorus cycle.

Question 20

Define Nitrogen Fixation

Answer 20

any natural or industrial process that causes free nitrogen (N2), which is a relatively inert gas plentiful in air, to combine chemically with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites

Question 21

What are reservoirs?

Answer 21

reservoir of an infectious agent is the habitat in which the agent normally lives, grows, and multiplies.

Question 22

Define Keystone species

Answer 22

an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether.

Question 23

What is the competitive exclusion principle?

Answer 23

that two species with identical niches cannot coexist indefinitely. Most of the explanations are niche-based in origin, including resource partitioning, character displacement, and niche trade offs.

Question 24

What is Interspecific competition?

Answer 24

the competition between individuals of different species.

Question 25

What is intraspecific competition?

Answer 25

a competition between individuals from the same species

Question 26

Define Carrying Capacity

Answer 26

a species’ average population size in a particular habitat. The species population size is limited by environmental factors like adequate food, shelter, water, and mates

Question 27

Describe Primary Succession

Answer 27

type of ecological succession in which plants and animals first colonize a barren, lifeless habitat.

Question 28

Describe Secondary Succession

Answer 28

type of ecological succession (the evolution of a biological community’s ecological structure) in which plants and animals recolonize a habitat after a major disturbance

Question 29

Define Pioneer species

Answer 29

describe the species that first colonize new habitats created by disturbance.

Question 30

A Climax community is..

Answer 30

An ecological community in which populations of plants or animals remain stable and exist in balance with each other and their environment