Unit A Pre-assessment
Completion requirements
Unit A: Interactions and Ecosystems
Pre-assessment: What do you know?
Figure A.P.1 – A Canada goose rests by a pond.
Figure A.P.2 – Canada geese foraging in a lakeside park.
Human activity can affect an ecosystem in unexpected ways. In the early 1900s, settlers over-hunted Canada geese for food. In addition, the birds lost some of their original habitat to human settlements. These human effects threatened the goose population
and their numbers dropped.
Then, human activities began to change. Goose hunting was restricted and we began to construct golf courses and public parks. Unintentionally, we produced perfect goose habitats. The geese could now munch on plentiful grass. Few predators came near them because the predators are afraid of human, and the geese could see approaching predators in the short mowed grass. Once threatened by human activity, Canada geese now benefit from humans. They are so plentiful today that many people consider them pests.
How did the changing goose population affect other species in the ecosystem? How has the wolf, its main predator, been affected? Should we control the size of the Canada goose population? If so, how?
To answer such questions, you need to understand how ecosystems work and how populations interact with each other. In this Interactions and Ecosystems unit, you will learn how human activity can affect ecosystems. You will learn how ecosystems are monitored and how energy and nutrients flow within ecosystems.
Then, human activities began to change. Goose hunting was restricted and we began to construct golf courses and public parks. Unintentionally, we produced perfect goose habitats. The geese could now munch on plentiful grass. Few predators came near them because the predators are afraid of human, and the geese could see approaching predators in the short mowed grass. Once threatened by human activity, Canada geese now benefit from humans. They are so plentiful today that many people consider them pests.
How did the changing goose population affect other species in the ecosystem? How has the wolf, its main predator, been affected? Should we control the size of the Canada goose population? If so, how?
To answer such questions, you need to understand how ecosystems work and how populations interact with each other. In this Interactions and Ecosystems unit, you will learn how human activity can affect ecosystems. You will learn how ecosystems are monitored and how energy and nutrients flow within ecosystems.
Figure A.P.3 – Canada Geese block a city street in their search for food.
Figure A.P.4 – A coyote carries its prey away.
Pre-assessment Questions & Hints
Step 1: The Questions
This short pre-assessment is to find out what you might already know about the topic of interactions and ecosystems. Below are four questions. Think about them! If you need a hint, click on the question.
Optional: If you would like a place to write your answers, download this document.
Optional: If you would like a place to write your answers, download this document.
How does the human activity affect food sources, shelter, predators, or behaviour? What about non-living factors such as sunlight, nutrients, and water?
Think about the wolf and goose. How do these species affect each other? How does an ecosystem maintain a balance of various populations?
Think about who eats what or whom in a particular ecosystem. Start with the special role of plants.
What kinds of things do we release into the air, water, and soil? How do they affect the organisms living there? What about the spaces we turn into houses, factories, farms, and parks?
Step 2: The Answers
Click each of the suggested answers below – how do they compare to your thoughts and answers?
Consider a honey bee gathering nectar from meadow flowers.
The bee needs nectar to live. It turns nectar into honey to feed its young. Various nectar-rich flowers are available all summer long. A farmer clears a meadow that by nature has a large variety of plants, and he plants one crop -- wheat. The wheat blooms during a single two-week period. For most of the summer, the honey bee has limited food. The bee population declines.
The bee needs nectar to live. It turns nectar into honey to feed its young. Various nectar-rich flowers are available all summer long. A farmer clears a meadow that by nature has a large variety of plants, and he plants one crop -- wheat. The wheat blooms during a single two-week period. For most of the summer, the honey bee has limited food. The bee population declines.
Canada geese eat grass. The wolf is a main predator. In the wild, the three populations keep each other in balance. When grass is plentiful, geese are plentiful and wolves are plentiful. In years of drought, geese and wolves decline because
they are interdependent on each other and on grass.
Consider the answer for Question 2. Grass captures the Sun’s energy. The goose eats the grass and obtains some of that energy. The wolf eats the goose. As one organism eats another, energy available as food moves up the food chain. Energy is
used by each organism so the amount available decreases as it flows from producer (grass) to primary consumer (goose) to secondary consumer (wolf).
Consider the bee problem in Question 1. A farmer could plant strips of wildflowers around the wheat field to offer the bees nectar all summer long. That way, he could provide some of the bee’s lost habitat and food source.
Step 3: Check In With Your Teacher
The start of a new unit is a great time to touch base with your teacher! Here are just a few reasons to consider contacting your teacher:
To contact your teacher, post in the Course Questions Forum, send your teacher an email, or call on the phone if you like. Whatever way you choose, it's always a good idea to get in touch with your teacher – make sure you do it frequently.
- Perhaps you found this pre-assessment quiz very easy because you have studied this material before, such as at another school. If so, it's important to tell your teacher.
- It's very good for your teacher to know you are starting a new unit; it will give them a good idea of your progress. It doesn't have to be a long message, just a "I'm starting Unit A; just thought you might want to know!"
- Your teacher may have special tips and suggestions for the unit you are starting.
- Just to say hi – your teacher always enjoys hearing from you!
To contact your teacher, post in the Course Questions Forum, send your teacher an email, or call on the phone if you like. Whatever way you choose, it's always a good idea to get in touch with your teacher – make sure you do it frequently.
