POPULATIONS: p.40

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            -

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 = ( 15 + 7) - ( 5 + 9)             =     (22)    -    (14)             =  + 8 Therefore, the population increases by 8. (a - negative answer would mean the population decreases)

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

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

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

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

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

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

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

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

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

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

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

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

Predator – Prey Relationship VIDEO: https://www.youtube.com/watch?v=5lR64UijfUQ

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