Download Strand 17: Review

SC.L.17.5 ANALYZE FACTORS THAT AFFECT THE
SIZE OF A POPULATION
Population size is determined by:
1.
Births
2.
Deaths
3.
Immigration
4.
Emmigration
5.
Limiting Factors biotics and abiotics
Abiotic Factors
Biotic Factors
Sunlight
Pathogens (cause disease)
Soil (type, ph)
Predator and pray (Predation)
Water
Competition
Natural disasters
(earthquakes, floods, tidal
waves, hurricanes etc)
Symbiosis
1. Mutualism
2. Commensalism
3. Parasitism
SC.L17.9: FOOD WEB
Use a food web to identify producers, consumers, and decomposers.
The more steps in a food chain the less efficient the energy transfer.
ENERGY TRANSFER AND REDUCTION OF
ENERGY
Explain the pathway of energy transfer through trophic levels and
the reduction of available energy of successive trophic levels.
The energy flows from producers to consumers, but some is lost to the
environment as heat due to metabolism in each of the lower trophic
levels.
SC.L17.20 IMPACT OF INDIVIDUALS ON
ENVIRONMENTAL SYSTEMS
Human activities may be increasingly harmful to ecosystems.
However unlike other organisms, humans can recognize their
impact on natural systems and change their behavior to minimize
those effects
1. Use of resources (renewable and nonrenewable)
2. Deforestation reduces biodiversity and increases erosion. The
removal of a forest will increase runoff on a river and it may
overflow
3. Greenhouse effect (the burning of fossil fuels increases the
levels of CO2)
4. Pollution (air, water, soil) The excess use of fertilizers
(nutrients) cause algal blooms in bodies of water. This is known
as eutrophication. Eventually fish and other aquatic organisms
will die due to the lack of oxygen, because bacteria use oxygen
when decomposing algae.