Warm-Up / EOC Prep1. An area with similar climate and characteristic

plants and animals, such as the desert or the tropical rainforest is known as a(n)A. biome B. ecosystemC. biosphere D. climate community

2. A hookworm (which feeds off of hosts) attached to the foot of a cat is an example of A. Commensalism B. CompetitionC. Parasitism D. Predation

Agenda• Warm Up• Quiz• Notes• Lesson of Kaibab• Clean Up• Raffle

• Article 2 Due Wednesday!

Population Growth

Guided Notes 7

Characteristics of Population Growth

• Geographic Distribution (range)-the area inhabited by a population

• Density-number of individuals per unit area• Growth Rate-how fast does the population

grow?

Three factors affect population size:

a. Number of birthsb. Number of deaths

If birth rate > death rate, population size increasesIf birth rate = death rate, population size stays the sameIf birth rate < death rate, population size decreases

What happens to the sea otter population if hunting decreases?

Population Increases!

What happens to the sea otter population if more killer whales are around?

Population Decreases!

c. Number of individuals that enter or leave the population

• Immigration-movement of individuals into an area

• Emmigration-movement of individuals out of an area

If a population has a lot of space and food and is protected from predators and disease, then organisms in that population will multiply and the population size will increase. Let’s say we have a single bacterium in a petri dish, and we give it all the nutrients and conditions it needs to survive and reproduce. How will the population change over time?

If the bacteria divide every 20 minutes, after one hour there will be 64 (248163264) bacteria, and after a day 4,720,000,000,000,000,000,000 bacteria will be present.

Exponential Growth

• Exponential growth (J-shape)- the individuals

in a population reproduce at a constant rate. Under ideal (excellent) conditions with unlimited resources, a population will grow exponentially.

Exponential Growth

Logistic Growth• However, in many habitats, resources become

less available, and population growth slows or stops. Logistic growth (S-shape)-a population’s growth slows or stops following a period of exponential growth. How might this happen?

Logistic Growth

How does logistic growth happen?

1. Death rate increases 2. Birth rate decreases 3. Number of predators increases 4. Resources decrease 5. Immigration decreases 6. Emmigration increases

Logistic growth continued…

• In logistic growth graphs, there is a point where the graph levels off and the growth rate = zero. This number on the graph represents the carrying capacity-the largest number of individuals that the environment can support.

REVIEW

Both species benefit from a relationship (win-win)

MUTALISM

One species benefits, the other is unaffected, like barnacles on a whale

COMMENSALISM

Another word for producer is?

AUTOTROPH

How much energy is transferred between each trophic level in an energy pyramid?

10%

What is the difference between primary and secondary succession?

•Primary succession-starts from scratch•Secondary succession-evolves from an existing community

Kangaroo rat

Coyote

Lynx

Bobcat

Anaconda

Baboon

Weasel

Caribou

Giraffe

• Homework:• Article 2 DUE Wednesday!!