1. POPULATIONS: p.40

2. POPULATION: (p. 42) - the number of a species in a given area
Factors that affect population size:
1.  births (natality)     +
2.  deaths (mortality)  -
3.  immigration          +
4.  emigration            -

3. Population growth: Growth = ( 15 + 7) - ( 5 + 9) = (22) - (14) = + 8
Growth = (births + immigration) - (deaths + emigration)
e.g.  A moose population experiences 15 births and 5 deaths. 7 moose move into the area and 9 move out.  What is the population growth?
Growth = ( ) - ( 5 + 9)
            =     (22)    -    (14)
            =  + 8
Therefore, the population increases by 8.
(a - negative answer would mean the population decreases)

4. Population Types: Open Population: -all four factors affect
- living things can come and go
- e.g. humans in Canada
Closed Population:
- only two factors affect (birth/death)
-living things CAN’T come and go
-  e.g. humans on Earth

5. Graphing Population Growth:
- Carrying Capacity: the maximum number of individuals an ecosystem can support                                                                                                                                             
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
population #
 - determined by limiting factors 
time
Workbook p.30

6. Limiting Factors:
(see workbook p.26-27)
resources that limit the size to which a population can grow
Brainstorm ideas
 density independent factors
-abiotic
- does not depend on population size
- Ecosystems climate
- Ex: temperature, precipitation, light, weather
living space, nutrients, water, oxygen

7. Limiting Factors: 2. density dependent factors Biotic
Depends on population size
Ex:        
competition→  food, water, space
         disease
         predation (predators)
parasites

8. Biotic Factors interact with each other in complex ways
Symbiosis- 3 forms

9. Predator-Prey Relationship
-the relationship in which one organism (predator) hunts and eats another (prey)

10. Competition
-a relationship where two types of organisms compete for the same resource such as food

11. Symbiosis - a relationship in which two organisms of different species 'live together' for a period of time

12. Parasitism - a form of symbiosis in which one organism derives nutrients from the second organism which suffers some harm but is usually not killed

13. Mutualism - a form of symbiosis in which both organisms benefit from each other
Purple martin bird being used by blowfly larvae

14. Commensalism - a form of symbiosis in which one organism helps the other organism, but there is no benefit nor harm done in return
The cattle egret, Bubulcus ibis, is a classic example of commensalism. It forages in fields among cattle and horses, feeding on insects stirred up by the grazing animals. The egret benefits from this relationship, while the livestocks are typically unaffected by it

15. Carrying Capacity
Carrying Capacity – the maximum population size of a species that a given ecosystem can sustain
Human actions such as farming and hunting can impact carrying capacity

16. Predator – Prey Relationship
VIDEO:

17. Quiz: Monday terminology matching!
Home work Pg. 59 #1-6
Review: Click on the link below
TED-ed population ecology (limiting factors)