Populations DO NOW – QUICK WRITE MIDTERM CHECK REFLECT ON YOUR PROGRESS BY ANSWERING THE FOLLOWING QUESTIONS. 1.WHAT IS YOUR QUARTER 1 GOAL FOR THIS CLASS? 2.WHAT IS YOUR CURRENT GRADE IN THIS CLASS? 3.WHAT % GRADE DID YOU GET ON THE LAST TEST? 4.WHAT DO YOU DO TO STUDY FOR EXAMS? 5.WHAT CAN YOU DO TO IMPROVE YOUR WORK HABITS IN CLASS AND AT HOME?

Homework and Announcements Due: Endangered Species Choice Notebook Check Ch: 5.1 and 5.2 Reading Notes USA TestPrep (due every Monday) Homework Start working on Research – Due Chapter 5.3 Reading / Notes

Populations L.O. SWBAT compare different types of growth in species populations.

5.1 Describing Populations ▪ Geographic Range ▪ Density and Distribution ▪ Growth Rate ▪ Age Structure

Describing Populations ▪ Geographic Range: The area inhabited by a population ▪ For some, the range is very small (bacteria) while others have a large geographic range (fish)

Describing Populations ▪ Density: The number of individuals per unit area -Ex: Small density of ducks versus large density of fish in a pond ▪ Distribution: how individuals in a population are spaced out across the range of the population - Randomly, Uniformly, or Clumped

Describing Populations ▪ Growth Rate: determines whether the populations increases (positive), decreases (negative), or stays the same.

Describing Populations ▪ Age Structure: the number of males and females of each age in the population Why? Most animals cannot reproduce until a certain age, and only females can produce offspring.

Population Growth ▪ Factors that affect population size are ▪ birth rate ▪ death rate ▪ rate at which individuals enter (immigration) or leave (emigration) the population

Population Growth Birth Rate ▪ Increases the population size if it’s greater than the death rate Death Rate ▪ Decreases the population size if it’s greater than the birth rate If birth rate = death rate, population stays about the same size

Population Growth Immigration ▪ Individuals moving into the area (grows the population) Emigration ▪ Individuals moving out of the area (decreases the population)

Exponential Growth ▪ The larger a population gets, the faster its population grows ▪ Under ideal conditions with unlimited resources, a population will grow exponentially ▪ Usually occurs with organisms that reproduce rapidly, mature at a young age, and produce many offspring at once.

Exponential Growth

Logistic Growth Organisms can’t grow exponentially… otherwise we’d have world domination! So what DOES happen?

Logistic Growth Phases of Growth: ▪ Exponential growth: resources are unlimited, few individuals die, more offspring are produced and reproduction is rapid ▪ Growth slows down: population is STILL growing, just at a much slower rate due to outside influences ▪ Growth Stops: rate of population growth drops to 0, population will usually remain stable at this size

Logistic Growth ▪ Most populations experience this kind of growth, especially when first introduced into the area ▪ What are some reasons that the population growth may slow down? ▪ Death rate increases ▪ Birth rate decreases ▪ Immigration decreases ▪ Emigration increases

Carrying Capacity ▪ The period at the end of the graph where it’s not growing is because it has reached its carrying capacity: the maximum # of individuals of a particular species that a particular environment can support.

Summary ▪ 4-5 Sentences about what we discussed. Today I learned about… ▪ Helper questions ▪ What is population? ▪ What factors affect population size? ▪ What is a carrying capacity?

CLASSWORK Pages 51 – 53 Record Q&A in Notebook Quarter 1 Project Checking for Notes 5.1, 5.2