Grade 12 Biology - Unit 5: Population Dynamics

Define Demographics

The statistical study of a population.

How are most populations controlled compared to human populations?

Most populations are controlled and limited by their natural environment, while human populations use technological intervention to modify the environment in order to live in areas that would not normally support the population.

How is population size limited?

Population size is limited by the availability of resources in an area. Where people choose to live is not random, but the original reasons may no longer exist in our modern world.

What are the four sections of the Human Civilization Model? Describe each section.

1. Pre-Industrial: The total population is low, death rate and birth rate are very close to each other.

2. Transition: The total population starts to increase as the death rate decreases and the birth rate stays relatively the same.

3. Industrial: The total population is still increasing as the death rate stays the same and the birth rate drops below the death rate.

4. Post-Industrial: The total population decreases as the death rate stays the same and the birth rate spirals up and down beneath the death rate.

In the Human civilization Model what is happening in the Pre-Industrial stage?

Pre-Industrial societies have stable populations but short life expectancies.

Agricultural yields are low leading to high food insecurity & a mostly rural population. There are no public health initiatives and no centralized education.

Current Examples: Stable & disrupted 3rd World countries.

In the Human civilization Model what is happening in the Transitional stage?

Transitional societies have rapidly increasing populations with much greater life expectancies.

Improved food security & ability to trade fuels a migration to cities & development of a middle class. There is improved health care & hygiene with some public health and sanitation in cities. Higher classes are increasingly educated, thus having fewer children.

Modern Examples: Industrialized 2nd World countries

In the Human civilization Model what is happening in the Industrial stage?

Industrial societies show slowing growth as the lower classes have increased life expectancy.

Food security continues to improve & surplus is widely traded. Increased access to healthcare and expanding public health initiatives outside of cities contributes to a declining birth rate. Public education of the middle class is extensive, with some education of the lower class, reducing the birth rate further.

Modern Examples: 2rd World countries with emergent economies.

In the Human civilization Model what is happening in the Post-Industrial stage?

Post-Industrial societies show declining native populations with high life expectancies.

There is widespread food security and universal access to health care. (Cost barriers may limit usage in countries without national funding.) Excellent public education of all classes, thus birth rate declines below replacement and growth only occurs due to immigration.

Modern Examples: Established 1st World countries

What is the Percent Population Equation?

% Pop. Change = [(natality + immigration) - (mortality + emigration)] / original population size

What is the expected human population size?

11 Billion

What are 3 reasons for a Growth Pattern?

1. Community interactions greatly influence population change, as populations fluctuate due to changes in resource competition and the presence of predators. Reproductive patterns also have a major impact.

2. Populations change: individuals are added or removed due to resource pressure.

3. Carrying capacity: Maximum sustainable population before competition overwhelms resources. This may result in a mass die off or forced relocation.

How did the Industrial Revolution affect us?

The population only started to double after the agricultural revolutions increased food security.

The Industrial Revolution improved our agricultural technology & expanded our public health initiatives leading to exponential population growth.

Density Dependent vs. Density Independent

Density Dependent: The effect is intensified the larger, more tightly packed the population.

Density Independent: Same effect regardless of population demographics.

What does competition do?

Lowers available resources and fitness of both the winners and the losers so it must be avoided.

What are causes of Mass Extinction?

Natural causes: have always occurred and can destroy habitat, limit food supply & reduce fitness. Human causes are very similar but they are not random events.

Define Ecology.

Ecology is the study of home.

A term coined by zoologist Ernst Haeckel, and it focuses on the interactions among all organisms and their environment. These interactions act as selection pressures that result in evolution. Modern ecology uses this understanding to make predictions about what will happen when these interactions change or are disrupted.

What are the COSWEIC Statues Level?

Extinct – beyond any help.

Extirpated – local extinction.

Endangered – immediate intervention required.

Threatened – intervention needed very soon.

Special Concern – (vulnerable) intervention needed in the future.

IUCN Red List: global status of all species for which there is a designation.

What COSWEIC Status Level is a Prairie Grizzly Bear? Why?

Extirpated from Canada (still persist in Alaska) from loss of habitat due to agricultural conversion of grasslands.

What COSWEIC Status Level is a Swift Fox? Why?

Endangered, habitat loss due to conversion of grasslands to agricultural uses, unintentional poisoning to control coyote & wolf populations (historic).

What COSWEIC Status Level is a Massasauga Timber Rattler? Why?

Threatened habitat loss due to human encroachment. Often killed due to bad reputation of rattlesnakes. Only venomous snakes in Ontario & can be encountered in our region.

What COSWEIC Status Level is a Spotted Gar? Why?

Threatened, habitat loss and pollution as they are sensitive to silt & eutrophication of waterways. Found in the Great Lakes Basin.

What COSWEIC Status Level is a Polar Bear? Why?

Special concern, habitat loss due to climate change and human encroachment (may be able to adapt as they are part of the brown bear family and this is being already seen in one population).

What is a Keystone Species?

A keystone species is one that has a significant influence on the viability of an entire ecosystem, which is often not noticed until the species is almost gone.

Define an Extinction Event.

A significant loss in a geologically short amount of time.

How often do species go extinct?

Everyday.

What three species are of value to us?

1. Aloe Vera plant

2. Burrowing Owl

3. Cattails

Why is the Aloe Vera Plant of value to us?

Collection of sap has many medicinal uses, especially for promotion of skin repair.

Why is the Burrowing Owl of value to us?

Restoration of habitat along agriculturally developed prairie has significantly reduced the need for insect control / pesticide use on crops. The owls feed on many of the insects and rodents that damage crops.

Why is the Cattails of value to us?

Restoration of small pond & seasonal wetlands has drastically reduced erosion and agricultural runoff into water systems / drinking water supply as they act as a natural filter.

What is Biodiversity key to?

Maintaining the health of Earth’s biome and its agricultural productivity.

What does “going green” mean for the economy?

Going green benefits both the planet and the economy by creating new industries and jobs, especially in green technologies, even if it limits some traditional economic development.

How do conservation and green technologies affect traditional industries?

Conservation can slow industries tied to fossil fuels, which have limited growth potential, while green technologies drive new economic opportunities and emerging jobs.

How does human development affect bushfire risk in Australia?

Development encroaching on wild areas increases the likelihood of bushfire ignition and puts more people at risk.

How does climate change affect bushfire seasons in Australia?

Climate change is making bushfire seasons longer and more intense due to higher temperatures and altered rainfall patterns.

What role does traditional Aboriginal knowledge play in bushfire management?

Aboriginal communities have long used traditional practices to live with and manage bushfire risk, and governments are now looking to this knowledge for future protection strategies.