Lynx & Hare Learning Objectives 1.Students will be able to calculate population density. 2.Students will be able to graph the size of a population over time. 3.Students will analyze the factors (biotic and abiotic) influencing population size and/or limiting population growth. 4.Students will analyze a population graph to identify areas of exponential growth and/or carrying capacity.

Lynx

Arctic Hare

Predator & Prey

Predator/Prey Relationship  What happens to a predator population when the prey population increases or decreases?  What happens to a prey population when the predator population increases or decreases?

Your Task 1.Your goal is to model changes in Lynx & Hare populations 2.Mark off your square with tape (2’ x 2’). This is your habitat 3.Use the Lynx and Hare cards to model how the numbers of individuals change over time

Important Reminders  Take care of the materials in this lab as several class periods will be using them.  Do not misplace, throw-away, crumple or otherwise destroy the one- inch snowshoe hares. Thanks for your help!

Analysis: Population Growth Population Growth is affected by: 1.Births 2.Deaths 3.Number who leave or enter the population

Real Lynx & Hare Data

Question: What was affecting the population of the lynx and hare in the activity?

Exponential Growth J-shaped growth In ideal conditions, a population will start growing slowly, then exponentially Example: in the right conditions, bacteria double their population each generation. Draw graph into your notes!

Limiting Factors Of course, organisms cannot grow exponentially for long Factors that limit the growth of a population are known as limiting factors Example: predation of hares by lynx limits the hare population

In the absence of lynx, what other factors might influence the size of the hare population? hare population?  Brainstorm in your groups

Factors can either be: - biotic (living factor) or - abiotic ( physical, non-living ) e population?  Classify each of the factors you brainstormed as biotic or abiotic.

Carrying Capacity  The maximum population that can be supported by an environment  The number is set by the availability of space, food, and other resources necessary for survival.

Carrying Capacity S-shaped growth As a result of limiting factors, population growth slows, or stops The result is a S- shaped curve The top of the curve is K (carrying capacity) Draw graph into your notes!

Example of S-shaped curve Question: what do you think might happen if a population exceeds the carrying capacity?