7 Ecosystems: Structure and Processes

Question 1

• oikos + logos
• “study of the home”
• study of relationships between
  organisms and the environment

Answer 1

Ecology

Question 2

• includes all the external conditions and factors,
  biotic and abiotic, that affect the life of an organism.
• consists of resources and conditions

Answer 2

Environment

Question 3

Anything an organism uses or consumes in the environment.

Answer 3

Resources

Question 4

Types of Resources:

• Inexhaustible in a human time scale e.g. sun

Answer 4

Perpetual

Question 5

Types of Resources:

• Available in a fixed amount; may be reused/recycled e.g. minerals

Answer 5

Nonrenewable

Question 6

Types of Resources:

• May be depleted but may ultimately be replaced by natural processes e.g. biofuels

Answer 6

Renewable

Question 7

– Use of resources without depletion

Answer 7

Sustained yield

Question 8

When use of resources goes beyond sustained yield, you have ___________

Answer 8

ENVIRONMENTAL DEGRADATION

Question 9

• Environmental factors to which organisms respond
  – e.g. temperature, salinity, humidity
• Influences availability of resources
• An organism’s survival depends on its tolerance to conditions

Answer 9

Conditions

Question 10

In life’s hierarchy of organization new properties emerge at each level

Answer 10

NOTE THIS

Question 11

The upper tier is a global perspective of life:

all the environments on Earth that support life

Answer 11

Biosphere

Question 12

The upper tier is a global perspective of life:
all the organisms living in a particular area; pathways
followed by energy and matter as these move among living and non living elements

Answer 12

Ecosystem

Question 13

The upper tier is a global perspective of life:

the array of organisms living in a particular ecosystem

Answer 13

Community

Question 14

The upper tier is a global perspective of life:

all the individuals of a species within a specific area;
presence/absence of species, abundance or rarity, trends and fluctuations in numbers

Answer 14

Population

Question 15

The middle tier is characterized by the organism,
an individual living thing, which is composed of:

Answer 15

Organ systems, organs, tissues

Question 16

Life emerges at the level of the cell, the lower tier,
which is composed of:

Answer 16

Molecules, organelles, cells

Question 17

• Light → producers (photosynthesis) → consumers → decomposers
• Energy diminishes as it passes through the ecosystem
• Energy is lost as heat
• Energy input must be continuous

Answer 17

Pathway of Energy

Question 18

a position in a food web and is determined by the number of transfers of energy from primary producers to that level

Answer 18

Trophic Level

Question 19

____________ limits the number of trophic levels in ecosystems

Answer 19

Energy loss

Question 20

Biogeochemical Cycles:

______ - the reservoir is the atmosphere (examples: N2 , CO2 , O2 )
______ - the reservoir is the earth’s crust (example: phosphorous).
______ - the reservoir includes major pathways in air, water and crust (example: sulfur)

Answer 20

1. Gaseous Type
2. Sedimentary Type
3. Linkage Type

Question 21

• A group of interbreeding individuals occupying a particular place at a
  particular time
• Is subject to change
  – In quantity by growth
  – In quality by evolution

Answer 21

Population

Question 22

______________ results from the net effect of all factors adding to the number of individuals in that population and those decreasing the number of individuals in that population. These factors in turn are the result of species characteristics and environmental conditions.

Answer 22

Population Growth

Question 23

Birth + Immigration or Deaths + Emigration =

Answer 23

Population change (either increase, decline, or remain-stable).

Question 24

Maximum number of individuals of one or more species that can be supported by a particular ecosystem on a long-term basis

Answer 24

Carrying Capacity

Question 25

Seldom does the growth rate of a population equal its biotic potential – its growth rate under ideal, nonlimiting
conditions. Environmental factors such as food supply, habitat, and disease limit growth

Answer 25

Biotic Potential and Environmental Resistance

Question 26

the maximum reproductive capacity of
a population under optimal conditions

Answer 26

Biotic Potential

Question 27

any factor in the environment that prevents a
population from expressing its biotic potential

Answer 27

Environmental Resistance

Question 28

change in plant, animal, and microbial communities in an area following disturbance or creation of new substrate

Answer 28

Community: Succession

Question 29

natural ecosystems are self-regulating

Answer 29

Cybernetics

Question 30

describes speed with which a community
returns to its former state after it has been
perturbed and displaced from that state.

Answer 30

Resilience

Question 31

describes the ability community to avoid
displacement in the first place.

Answer 31

Resistance

Question 32

Key Concepts and Principles

Answer 32

1. The components of the ecosystem (biotic and abiotic) are continually interacting and exchanging materials and energy.
2. The biotic components of an ecosystem include the producers, consumers and decomposers; the abiotic components refer to the climate, soil and topographic factors.
3. Ecosystem functions cover the major life sustaining processes that include food webs, energy flow, nutrient cycling, biodiversity, change and cybernetics.
4. In a food chain, there exists a feeding relationship in which energy-rich molecules stored by producers are taken in by a series of consumers.
5. There is a one-way flow of energy in an ecosystem. Entering the living world mostly as light through the trophic chain, energy leaves mostly as heat.
6. Materials flow in an ecosystem in a cyclic pattern. Materials utilized by the biotic components of the ecosystem return to the physical world mainly through the processes of respiration and decomposition.
7. Biodiversity is important, because every living species has a role to play
8. Everything changes. Organisms, populations and communities change as expressed in growth and development.
9. A balanced ecosystem is achieved when the natural processes involved are maintained in a dynamic steady state

Question 33

• Complex interactions exist between the living
  and non-living components of the
  ecosystem.
• The structure and function of ecological systems are interrelated with socioeconomic systems

Answer 33

Interdependence

Question 34

• Concerned with applications of ecological principles to major environmental
  and resource management problems
• Forest, range, wildlife and fishery management
• Conservation biology, restoration ecology, landscape ecology

Answer 34

Applied Ecology