1. Unit 1: Populations and How they Change

2. Remember!!!!!
Write all notes in your note book, using the indents and titles
If the title repeats, then you do not need to rewrite it again
Highlight all vocab words that are bolded, and highlight all things that say definition so you will be able to find them later
If there are directions for you to draw something, you must draw that in your notes.

3. What is a Population?
Definition Individuals of the same species living in a particular area
Examples of a population: Cows in a Field
Bees in a Hive
Students in a classroom
Maple Trees in a Forest
Species can be made of many populations in different areas
Example: Not all cows are found in one field

4. Why do we study populations?
We study populations to:
See how they change over time (size, distribution, density)
See how their populations change their environment, either negatively or positively
For humans, we study our population to see if there is enough resources for our species to survive

5. How are populations Described?
Populations are described by three characteristics:
1. Size
2. Density
3. Distribution

6. Characteristic of a Population
1. Size of a Population
Definition The number of individuals in a population
This number will increase and decrease due to many factors

7. Characteristic of a Population
1. Size of a Population
Factors that can Change the Size of a Population
Births Increase a population
Deaths  Decrease a population
Immigration (people come into a country) Increase a population
Emigration  (people leave a country) Decrease a population
Lack of resources  Decrease a population
Abundant (lots of) resources Increase a population

8. Characteristic of a Population
2. Density of a Population
Definition Number of individuals in a given area
If there is a lot of organisms in an area, then it is called a dense population
If there are few organisms in an area, then it is called a sparse (spread out) population

9. Characteristic of a Population
3. Distribution of a Population
Definition How organisms are arranged in an area
When populations are widespread across the globe, like humans, there is more access to resources and a better chance for survival
When populations are only found in a few spots, lack of resources and isolation will decrease their chance of survival

10. Limiting Factors of a population
If left unchecked, and with unlimited resources, populations would continue to grow and grow. But, because this does not happen in real life, there are limits to how big a population can get.
Definition Factors that slow the growth of a population
These can be controlled (density-dependent) or uncontrolled (density-independent)

11. Limiting Factors of a population
Density Dependent Factors
Definition Factors that are controlled by the size of the population
Examples: Food
Water
Disease
Density Independent Factors
Definition  Factors that are outside the control of the population
Examples: Floods
Fires
Hurricanes

12. When Does a Population reach its Carrying Capacity? (Draw Graph)
Definition The amount of organisms that an area can support without negatively affecting the environment
When resources are low, populations will decrease
When resources are high, populations will increase
There is constant fluctuations in population size

13. When does a population reach its biotic potential?
Definition Maximum ability to produce offspring in ideal conditions
Meaning the amount of children that organisms can have in a perfect environment
Good conditions Lots of offspring
Bad Conditions Less offspring

14. How do populations grow? (draw these Graphs)

15. Types of Population Growth
Exponential Growth
Logistic Growth
Definition Population continues to grow at an increasing rate
No limit to its size
Has unlimited resources
Sometimes called a J-Curve
Definition  Population increases at first, then slows to a limit due to resources (food, water, shelter)
Reaches a limit that the environment can hold
Has limited resources
Sometimes called an S-Curve

16. Human population is different
The human species has learned to overcome our limiting factors
Examples:
Medicine takes care of diseases
Can grow our food in almost any environment
Build our shelters anywhere we want
We can evacuate areas that are affected by natural disasters

17. Human population is different
We are growing exponentially because we have learned to manipulate our environment and spread all over the globe
With our rapid growth, we are using resources too quickly which means we are going to run out and our population is going to hit our carrying capacity in the near future.
Right now, we have not exceeded our carrying capacity

18. Human population is different (draw this graph with years at the bottom))