Populations and Resources Section 2! Text: 2.5

Populations What is a species? Are these 2 animals in the same species?

Species A group of similar organisms that can mate with each other and produce fertile offspring  Male donkey + female horse = mule (infertile)

Interesting Species… Liger! Female Tigress Male Lion +

Interesting Species… Female lion + Male tiger = Tigon!

Interesting Species… Leopon!

Interesting Species… Jaglion!

Populations Populations: all the individuals of a species that occupy a particular geographic spot at the same time  South African elephants in Kruger National Park  A species of frogs in a pond

Populations Community: All the different species that interact in a specific ecosystem  Eg. A swamp

Exponential Growth How does a population grow? Exponential growth of a population can occur under certain circumstances  Wealth of resources (Eg. algae)  Removal of pressures Protection from natural predators Protection from hunters (Eg. elephants)

Exponential Growth Def: accelerating growth that produces a J- shaped curve when the population is graphed against time

Species Re-introduction The Ontario wild turkey was plentiful prior to the 19 th century Deforestation and hunting were severe and devastated the population

Species Re-introduction The provincial government re-introduced the wild turkey in the 1980s when  southern Ontario’s forests were renewed  protection plan was established From , 4400 turkeys were released By 2001  population was By 2008  population was  (exponential growth)

Exponential Growth and Limiting Factors Exponential growth cannot be sustained indefinitely  Why?? No ecosystem has an unlimited supply of resources  Food  Water  Shelter These restrictions are called “limiting factors”

Limiting Factors Def: an environmental factor that prevents an increase in population number or prevents them from moving into new habitats As a population grows, each individual has less access to resources This limits the growth of the population

Carrying Capacity Def: the size of a population that can be supported indefinitely by the available resources and services of an ecosystem Beyond this capacity, no additional individuals can be supported

Equilibrium When a population is maintained at its carrying capacity, the size of the population is in equilibrium balance between individuals that join the population and the number that leave or die = “zero population growth” Growth Rate: Births – deaths + immigration - emigration x 100 =__% initial population

Urban Sprawl As humans alter ecosystems to fit their needs, the carrying capacity changes Urban sprawl is used to describe a city’s growth as population increases People build new homes and businesses near outer edges of cities  Creates:  more dependence on cars  decreased farmland  decreased carrying capacity for native organisms

Urban Sprawl A city’s growth as it’s population increases  More and more development on the ‘outskirts’ of a city

The Golden Horseshoe West end of Lake Ontario