Population Change

in Ecosystems

7th GradeUnit 6

Module 1

Which animal in the Animal Kingdom is most like YOU? Why?

Watch power of 10 ppt

• We are each most like another human being, biologically speaking= A good reason for Mutual Respect, in and out of the classroom

• Applied to Ecosystems, we see that human beings are part of every Ecosystem on the Earth. We impact all parts of the ecosystem, including each other (the human population).

How does the human population change? Discuss

• Is there an overall increase or decrease?

Population evolution in different continents. The vertical axis is logarithmic and is millions of people. Taken from Wikipedia

• Think of recent news items…

Review Vocab

• Ecosystem: A system of interacting organisms (biotic) and nonliving factors (abiotic) in a specified area

• Population: all of the individuals of one kind in a specified area at one time

• Community: all the interacting populations in a specified area

Population Change

• Population: all of the individuals of one kind in a specified area at one time

• So, what is population change? It refers to the # of individuals of that population (could increase or decrease)

Example: Lyme Disease in NJ & PA

But, why had the deer population increased?

Human Impact: Killing Natural Predators (Secondary Consumers)

Reproductive Potential: the theoretical unlimited growth

April 15:1. How does a population change?

2. How does the number of individuals in a population increase (how does the population grow?)

View Simulations of Milkweeds

• Unlimited: What if Milkweeds just reproduced and reproduced with nothing to limit its population?

• Limited: But, there are things that limit their population. What are those things?

We call them “Limiting Factors”. Do worksheet.

April 17

•Did you floss last night?•Why or why not?

April 17: Quickwrite

Name 3 abiotic factors that affect the Milkweed population?

1. How do you think these abiotic factors

affect the Monolake Ecosystem?

Algae and Brine Shrimp Population

• Let’s go back to Monolake…• Review Monolake Food Web: algae

and brine shrimp and trophic levels• Experimental Design

Discussion

1) Was this a real experiment? Why or why not?

2) What were the dependent, independent, and controlled variables?

3) What were the results?4) What is, then, the main limiting factor for

each population studied?

Create Claim Table

Claim Evidence Reasoning

April 20: Quickwrite

During what month(s) do you think the algae population in Monolake is the biggest?

Why?