7 Ecosystems: Structure and Processes Flashcards
- oikos + logos
- “study of the home”
- study of relationships between
organisms and the environment
Ecology
- includes all the external conditions and factors,
biotic and abiotic, that affect the life of an organism. - consists of resources and conditions
Environment
Anything an organism uses or consumes in the environment.
Resources
Types of Resources:
- Inexhaustible in a human time scale e.g. sun
Perpetual
Types of Resources:
- Available in a fixed amount; may be reused/recycled e.g. minerals
Nonrenewable
Types of Resources:
- May be depleted but may ultimately be replaced by natural processes e.g. biofuels
Renewable
– Use of resources without depletion
Sustained yield
When use of resources goes beyond sustained yield, you have ___________
ENVIRONMENTAL DEGRADATION
- 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
Conditions
In life’s hierarchy of organization new properties emerge at each level
NOTE THIS
The upper tier is a global perspective of life:
all the environments on Earth that support life
Biosphere
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
Ecosystem
The upper tier is a global perspective of life:
the array of organisms living in a particular ecosystem
Community
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
Population
The middle tier is characterized by the organism,
an individual living thing, which is composed of:
Organ systems, organs, tissues
Life emerges at the level of the cell, the lower tier,
which is composed of:
Molecules, organelles, cells
- Light → producers (photosynthesis) → consumers → decomposers
- Energy diminishes as it passes through the ecosystem
- Energy is lost as heat
- Energy input must be continuous
Pathway of Energy
a position in a food web and is determined by the number of transfers of energy from primary producers to that level
Trophic Level
____________ limits the number of trophic levels in ecosystems
Energy loss
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)
- Gaseous Type
- Sedimentary Type
- Linkage Type
- 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
Population
______________ 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.
Population Growth
Birth + Immigration or Deaths + Emigration =
Population change (either increase, decline, or remain-stable).
Maximum number of individuals of one or more species that can be supported by a particular ecosystem on a long-term basis
Carrying Capacity
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
Biotic Potential and Environmental Resistance
the maximum reproductive capacity of
a population under optimal conditions
Biotic Potential
any factor in the environment that prevents a
population from expressing its biotic potential
Environmental Resistance
change in plant, animal, and microbial communities in an area following disturbance or creation of new substrate
Community: Succession
natural ecosystems are self-regulating
Cybernetics
describes speed with which a community
returns to its former state after it has been
perturbed and displaced from that state.
Resilience
describes the ability community to avoid
displacement in the first place.
Resistance
Key Concepts and Principles
- The components of the ecosystem (biotic and abiotic) are continually interacting and exchanging materials and energy.
- The biotic components of an ecosystem include the producers, consumers and decomposers; the abiotic components refer to the climate, soil and topographic factors.
- Ecosystem functions cover the major life sustaining processes that include food webs, energy flow, nutrient cycling, biodiversity, change and cybernetics.
- 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.
- 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.
- 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.
- Biodiversity is important, because every living species has a role to play
- Everything changes. Organisms, populations and communities change as expressed in growth and development.
- A balanced ecosystem is achieved when the natural processes involved are maintained in a dynamic steady state
- 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
Interdependence
- 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
Applied Ecology
