Bell Ringer! Do the quick write on the bottom of page 14 (Biomes page). Intestines! Also, add that your independent variables also included the heterotrophs & autotrophs for the Eco- Zones!

Nitrogen and Carbon Cycles Page 9

Cycling of Nutrients: Carbon Cycle

Cycling of Nutrients: Nitrogen Cycle

Population Growth Page 17 How fast do populations grow? Starts slow…increases fast Exponential growth = “J curve”

Population Growth Will populations keep increasing? No! something always runs out Called “limiting factors” Limiting Factors- resources that limit the growth, abundance, or distribution of an organism or population of organisms in an ecosystem Can you think of any examples?

Population Growth Two types of limiting factors: Density dependent More affected when population is larger Examples: food, water, shelter Density independent Does NOT matter how many are in the population Examples: flood, tornado, etc

Population Growth So, how many can live in a habitat? Carrying capacity # of organisms environment can support If population goes above the CC, death rate will increase

Population Growth

Variations in Population Growth Populations of organisms have highly variable patterns of growth What does this data indicate about the growth pattern of each population?

Growth Strategies Population growth is controlled by two things: ~ Carrying capacity of environment (K) ~ Rate of reproduction (r)

r Selection: reproduction rate is more important These organisms… Have a high growth rate Tend to be in disturbed habitats Have “Type III” curve…early losses Rapid development…short lives

K Selection: hovers near carrying capacity These organisms… Have fewer offspring Tend to be in stable habitats Have “Type I or II” curve…constant or late loss Slower development… longer lives

r and K Strategies

Age Structures & Mortality Population growth is influenced by age structure within a population Higher #s in the “reproductive ages” means more growth Which population is growing the fastest? The slowest? How do you know?

Page 12- Reflections Write 5-7 sentences reflecting on what SYMBIOSIS meant to you Write 5-7 sentences reflecting on what POPULATION GROWTH meant to you