This document discusses populations and their characteristics. It defines key population terms like population, community, ecosystem. It explains that a population's size is determined by births, deaths, immigration and emigration. Limiting factors like competition, predation, disease, climate and human impacts can cause population changes by limiting growth. The carrying capacity is the maximum population size an environment can sustain given limiting factors.

1. Unit 1 Notes:
Populations

2. Where did we
come from?
• The processes that
individual organisms do
to convert and cycle
energy and matter
throughout an
ecosystem.
• Photosynthesis, Cellular
Respiration, Food
Chains/Webs
Where are
we going?
• The processes that
impact the ability of
groups of organisms to
cycle energy and matter
throughout an
ecosystem.
• Population Changes,
Biodiversity, Human
Impact, Climate Change

3. (1) Ecosystem Levels
•Organism: 1 living thing.
•Population: A group of the same types of
organisms.
•Community: A variety of types of populations
living together.
•Ecosystem: A specific environment with
unique biotic and abiotic factors.

5. (2) Population Characteristics
•Populations are studied and monitored by 3
characteristics:
•Geographic Distribution:
The area/s inhabited by the population.
•Density:
Number of organisms per unit area within the
population’s habitat.
•Growth Rate:
How fast the population increases or decreases in size
over time.

6. 6 July 22, 2012 Footer text here

7. 7 July 22, 2012 Footer text here

8. (3) Population Size
•4 Factors affect the size of a population:
•Number of births
•Number of deaths
•Number of organisms entering (immigrating).
•Number of organisms leaving (emigrating).

10. (4) Population Changes
Anything that alters how the different
organisms cycle energy and matter to
one another, will cause changes to the
population.

12. (5) Limiting Factors to Population Size
•A Limiting Factor is something that stops a
population from continuously growing larger.
•There are 2 Types:
•Density Dependent  Factors that directly relate to
how many organisms there are.
•Density Independent  Factors that have no
relationship to the number of organisms there are.

14. (6) Density Dependent Factors
•Competition between organisms for resources.
•Predation (organisms being hunted).
•Parasitism (organisms invading other living
structures and withdrawing all resources).
•Disease.

15. (7) Density Independent Factors
•Human Disturbances & Activities.
•Climate Change.
•Natural Disasters.

16. (8) Carrying Capacity
•The Carrying Capacity of a population is
the largest number of individuals that a
given environment can support.
•Limiting Factors determine the carrying
capacity of any population.