INTERACTIONS OF LIVING THINGS 5 A SCIENCE FS

INTERACTIONS OF LIVING THINGS 5 A SCIENCE FS 2017

POPULATION DYNAMICS Unit 1 Lesson 3 Essential Question: What determines a population’s size? Lesson Objective Students will be able to explain how population size changes in response to environmental factors and interactions between organisms

Vocabulary Word part ime-migrate Meaning into out move With this in mind, please answer the following questions: What does “immigrate” mean? What does “emigrate” mean”

How can a population grow or get smaller? birth immigration death emigration

What environmental factors influence population size? availability of resources (e. g. food, water, space) changes in the environment • rainy season • dry season • natural disasters (e. g. forest fire) • harsh weather (e. g. drought)

What factors can limit population size? A part of the environment that keeps a population’s size at a level below it full potential is called a “limiting factor”. Limiting factors can be living or nonliving things in an environment. biotic factors abiotic factors

What interactions between organisms can influence population size? competition Two or more individuals or populations try to use the same limited resource such as food, water, shelter cooperation Individuals working together e. g. some animals work together to hunt in groups

Classwork Answer the following questions in your NBs: 1. How can cooperation help organisms survive? 2. Look at the picture on page 41 in your science books. Ø What might cause birds in population A to immigrate to the island? Ø How will the level of competition among birds in population B change if many birds from population A join population B?

Homework Find definitions for science vocabulary: Ø carrying capacity Ø competition Ø limiting factor Ø cooperation