OUR PLANET Unit 1-4a Understanding Populations For this unit only… Please use the abbreviation Pop. to represent Population. This will greatly reduce the time it takes to write population over & over again.

How Do Populations Change? Imagine that you are responsible for monitoring the quality of life for a population of puffins. What data would you collect to make your evaluation? Growth Rate – Measures the change in population size by subtracting the number of deaths from births. A successful population would have a positive growth rate. You could also measure… Population Density – The number of individuals in an area or Dispersion – How individuals are distributed in an area Even, Clumped, or Random – Which are puffins?

When Do Populations Stop Growing? To see if the puffin population is growing successfully, you’ll need to know its potential for growth. Reproductive Potential – The maximum number of offspring that a population can produce. A female elephant can theoretically produce 19 million descendants in 750 years Bacteria can produce 19 million descendants in 150 hours But a female puffin can only produce one egg per year. Does that mean that every female will reproduce and have an offspring that lives to adulthood?

What’s A Good Population Size? Because the environment is always changing & resources are limited, populations don’t reach their full potential. Carrying Capacity – The maximum population that the environment can support for a long period of time The population may exceed or fall below the carrying capacity but it is a good estimate of the expected population size. The carrying capacity is generally set by a… Limiting Factor – A resource needed by a population that limits its continual growth; Ex: Sunlight, food, water What limits our puffin population?

Other Population Factors Two types of limiting factors that affect population size. Density Dependent – Expected deaths increase as a result of a larger population; Ex: limited resources & predation A crowded population will have less resources to share and attract more predators or Density Independent – Expected deaths increase regardless of population size; Ex: Extreme weather & natural disasters Can all of these factors relate to human populations?

Close Your Notebooks… What have you learned in this unit? 1. Explain what a negative growth rate would indicate. 2. Would a school of fish in the ocean show even, clumped or random dispersion? 3. Does a person or a cat have a greater reproductive potential? 4. Describe what happens when a population exceeds its carrying capacity. Why? 5. Is starvation density dependent?

OUR PLANET Unit 1-4b Human Populations

Human History Demography – The study of human populations The history of our human population was fairly stable until the 1800s when our population experienced… Exponential Growth – A growth rate that continues to increase each year Demographers predict a world population of 8 billion by the year 2025.

Forecasting Populations There are four factors that influence predictions… Age Structure – The distribution of age in a population Using a population pyramid, it’s clear that a wide base of young people indicates a better chance for growth. Survivorship – Percentage of a population that are expected to survive to the next age level Which of these lines represents the survivorship of a… a) Fruit Fly, b) Human, c) Sea Turtle

Forecasting Populations Fertility Rates – The number of babies that will be born per 1,000 women Most countries have a fertility rate less than 3. Yet an average women in Africa may have as many as 6 kids. Migration – Immigration and emigration between countries also affect populations. In developed countries, have immigration or emigration rates increased?

The End Of Death? In the past 200 years, life expectancies, the average age a person dies, has increased dramatically due to… Adequate Food Clean Water Safe Waste Disposal Advances in Medicine The average lifespan has increased from 40 to over 80 for many developed countries while infant mortality rates have dropped. More successful births + less deaths = larger population

How Long Can This Continue? Do these graphs look similar? Our growth rate and population density continue to increase, so what happens when we reach our… Carrying Capacity – The maximum population that the environment can support for a long period of time

But Human Populations Are Different! Demographic Transition – A model that describes the four stages of human populations Stage 1 – Preindustrial Birth & death rates are high Stage 2 – Transitional Death rates drop as a result of education; Birth rates decrease slowly so the population grows Stage 3 – Industrial A large population with low birth and death rates Stage 4 – Post Industrial Populations begin to decrease

So Maybe There’s Hope If developed countries can spread education and wealth across the globe, there’s a chance we’ll be just fine

Close Your Notebooks… What have you learned in this unit? 1. Besides people, what other organisms grow exponentially? 2. Describe the age structure for the people living in your home. 3. List one factor that affects women’s fertility rates. 4. What factors have allowed our life expectancy to increase? 5. Because our population is stable, at which stage is the U.S. in demographic transition?

OUR PLANET Unit 1-4c Human Habitats

Where Do All The People Go? Land Cover – What is find on an area of land; Might be… Urban – Mostly buildings & roads Suburban – Residential areas outside of a city Rural – Open land with few homes Crop & Range Land – Used for farming and livestock Wilderness – Natural land protected from exploitation There are more than 6 billion people and for the first time in history more than half of them live in cities!

Where Are We Going? Does it ever seem like we will stop building new homes and businesses in Edison? Urban Sprawl – The expansion of cities into suburban and rural areas Each year 2.5 million acres of land is developed upon to build suburban communities. Do you recognize this road? Does this help? This is what it looked like 75 years ago. How will it change in your lifetime?

The City Life! Widespread urbanization has led city leaders to evaluate how they design cities and use the land. Land-Use Planning – Determining in advance how land will be used; Homes, businesses, industry, parks and… Infrastructure – All public structures including Roads & Bridges Police & Fire Dept Schools & Hospitals Power lines & Sewers When cities outgrow their infrastructure it can cause traffic, power outages, & lack of critical services

Tools Of The Trade Geographic Information System (GIS) – Computer program that stores & manipulates data for all city elements It can be simple… “Do we have enough fire hydrants?” or detailed… “How many customers live in a flood zone?” or very complex… “Where would be the best place to build a warehouse for our 11 businesses?” Urban planners on average made $70,000 last year.

Close Your Notebooks… What have you learned in this unit? 1. List five forms of land cover. 2. List one urban, one suburban, and one rural city in New Jersey? 3. Where can wilderness be found in New Jersey? 4. Describe some of the problems with the infrastructure in Edison. 5. Which variables can be used for land-use planning using a G.I.S. program?