Populations

A Population group of organisms of the same species living in the same place at the same time

Different populations are all connected! When one population decreases or increases in an ecosystem, another population can be affected! Example: The story of the sea otters!

Figure 1.15 page 18

When the sea otters are absent…

Carrying Capacity The maximum population that an environment can sustain or support. Seychelles Paradise Flycatcher needs one acre of mixed forest per breeding pair. They live on the little island of Madagascar

Carrying Capacity a population remains at its carrying capacity when in balance (number of individuals added and the number of individuals that leave or die are the same)

Factors Determining Carrying Capacity materials & energy: energy, water, carbon, and other essential nutrients (Abiotic Factors)

Factors Determining Carrying Capacity 2. Food chains: the population size is limited by the size of the populations at lower trophic levels

Factors Determining Carrying Capacity 3. Competition: each organism has the same need as any other; they compete for resources such as food, water, mates and space

3. A closer look at Competition: Two types of competition: Intraspecific competition: among members of the same species ex: two wolves compete for a rabbit Interspecific competition: between different species ex: cheetah and lion compete for zebra

4. Population Density: depending on their size, environment and way of life, different species have different needs for space

Density Dependent Factors Occur when the density has gone beyond an appropriate level Over-population can: Increase stress & lead to easier spread of diseases and parasites Increases aggression & causes parents to neglect offspring This causes the population to decrease

Density Independent Factors Limits the population- no matter what the density is. Forest fires Earthquakes Volcanic Eruptions Tornadoes Floods

Video - Populations Ecology - Crash Course

To Do: Vocab words: Exponential growth Limiting Factor Population Carrying Capacity P. 290 #1-4