Populations and Resources Section 2! Text: 2.5. Populations What is a species? Are these 2 animals in the same species?

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 TigressMale Lion

+

Interesting Species…

Female lion

+ Male tiger

= Tigon!

Interesting Species…

Leopon!Leopon!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 19th 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 1980-2000, 4400 turkeys were released By 2001 population was 30 000 By 2008 population was 70 000

(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