Biology Unit 3 Humans and Global Change IHS Skavaril

What is the sex ratio of males to females

50:50

What does the sex ratio show

Shows the # of babies that will be produced next generation

What does age structure graphs show

Whether or not populations are increasing, decreasing, or stable over time. They illustrate the distribution of various age groups within a population

What is population growth rate affected by

1. Birth

2. Death

3. Immigration

4. Emigration

Including the basic 4 factors, HUMAN population growth rate affected by

1. Culture

2. Conflict

3. Economy

4. Politics

5. Resources

What does a demographic transition model show

Change in population from high birth and death rates to low birth and death rates

What is stage 1 in an age structure diagram

High fluctuating; majority of population is young

What is stage 2 in an age structure diagram

Early expanding; steady decrease from young to old

What is stage 3 in an age structure diagram

Late expanding; majority of the population is young adults/teens

What is stage 4 in an age structure diagram

Low fluctuating; adults make up more of the population—still a “healthy” amount of younger children

What is stage 5 in an age structure diagram

Decline; majority of the population are older adults—population of young children are decreasing

How has human population change over time

It increased/grew

How has human activities change the atmosphere and climate

• Created the Anthropocene

• Human emission of greenhouse gases (carbon dioxide, nitrous oxide, methane) drive climate change

Describe how atmospheric changes drive climate change

Greenhouse gases (CO2 and methane) in the atmosphere act as an insulator (keep heat in). This heat is changing the global temperature and driving climate change

What greenhouse gas does cows release

Methane

What are three major greenhouse gases

Carbon dioxide (CO2), methane, nitrous oxide

What are the effects of CO2 emission

• Increase in temperature

• Increase in sea levels

• Decrease in ice caps

What are 4 countries in stage 5 of the demographic transition model

Italy, Russia, Germany, Japan

What are the characteristics of a stage 1 demographic transition model

• Stable population

• High birth and death rate

• Birth and death rate are about the same

• Pre-industrial society

• Population essentially determined by the food supply

• Family planning and contraception are virtually nonexistent

• Population fluctuates rapidly due to natural events

• Examples: Angola, Amazon basin tribes

What are the characteristics of a stage 2 demographic transition model

• Increasing population

• High birth rates and decreasing death rates

• Developing countries

• Improvements in food and water systems

• Improvements in medicine/public health

• Examples: Kenya, Ethiopia, Yemen, Afghanistan

What are the characteristics of a stage 3 demographic transition model

• Increasing population

• Birth rate begins to decrease and low death rate

• The value of women increases

• Increased access to contraceptives (condoms, birth control, etc.)

• Increasing urbanization

• Examples: India, Mexico, South Africa

What are the characteristics of a stage 4 demographic transition model

• Stable population

• Low birth and death rates

• Children are a choice

• Increase access to family planning

• Women are more independent and gain more work opportunities

• Low rates of diseases and high production of food

• Examples: Canada, United Kingdom, United States, Turkiye, Guam, Peru

What are the characteristics of a stage 5 demographic transition model

• Decreasing population

• Decreasing birth rate and death rate is higher than birth rate

• Children are an option and people are CHOOSING NOT TO HAVE CHILDREN

What are 8 human impacts to the Earth

1. Acid rain

2. Ocean acidification

3. Biological magnification

4. Deforestation

5. Monoculture

6. Habitat fragmentation

7. Overharvesting

8. Invasive species

What is acid rain

When air pollution combines with water and falls as rain that is acidic and especially damaging to forests and lakes

What is ocean acidification

When the water continues to decrease in pH due to carbon dioxide absorption from the atmosphere. More CO2 in atmosphere → more CO2 dissolves into water → water becomes more acidic → acidity dissolves shells

What is biomagnification

The increase concentration of a substance (usually pollutants) in organisms as the food chain level goes up

What is deforestation

The loss of forests, which has negative effects on soil, water, carbon storage, and animals

What is monoculture

When humans plant large areas with a single, high production crop every year (NO BIODIVERSITY)

What is habitat fragmentation

When parts of a habitat are destroyed, leaving behind smaller unconnected areas. This causes biodiversity loss and makes ecosystems more vulnerable to other disturbances

What is overharvesting

When humans use a natural resource in an unsustainable way

What are invasive species

They are species that can be introduced to new places by humans and disrupt the ecosystem