Diversity of Life Investigation 9: Roaches

At the end of Investigation 9 you will be able to: Describe the anatomy of insects. Define and list examples of adaptations. Design an experiment to learn more about cockroach behavior and preferences. Make inferences about the habitat of various insects based on their characteristics.

Investigation 9 - Part 1 Introducing Insects

ORGANISMS So far we have investigated many different types of organisms: paramecia, yeast, brine shrimp, snails, several plants, and other single-celled and multi-cellular life forms. They are all different, but even so, they all have many things in common.

We haven’t, however, studied the largest group of organisms on Earth We haven’t, however, studied the largest group of organisms on Earth. In fact, there may be many more species of these organisms of these organisms on Earth than all the other species put together. They are found in every continent, in the air, and in the fresh water the world over. They are so important in the biosphere that many other species could not survive without them. Because of this, many scientists feel that they rule the planet. What group of organisms do you think this is?

No. I have 200 million insects. I have 200 million insects. I beg to differ. I have 200 million insects. You’re all wrong because I have 200 million insects. You’re all correct. For every person on the planet, there are 200 million insects.

Adaptations: DOL text p. 55 Read the article The Insect Empire. Please go to pages 56 and 57 in your lab notebook. Work in your groups to answer the first two questions.

Let’s use the right terms.

INSECT ADAPTATIONS Insects, like other organisms, have structures and behaviors that help them to survive. Structures and behaviors that increase an organism’s chances of surviving and reproducing are called adaptations. No other group of organisms has a greater variety of adaptations than insects. Let’s consider a mosquito as an example.

MOSQUITOES 1. What do you know about mosquitoes? 2. What do they eat? Females tap blood from a host in order to nourish their developing eggs. 3. How do mosquitoes find their prey in the dark?

MOSQUITOES 4. How do mosquitoes extract their blood? The mosquito has a tube that it pushes through skin to suck out blood. 5. When do you usually notice a mosquito bite, at the time she is biting you or after she has left? Doesn’t hurt or itch until later.

MOSQUITOES Everything about the piercing mouthparts of the female mosquito is adapted for tapping blood. The proboscis, often incorrectly called a stinger, is equipped with specialized tools for the job. It has sharp “scalpels” for cutting through your skin, “clamps” to hold the wound open, and a straw-like mouthpart it uses to suck up the blood. Mosquito saliva has chemicals that keep blood from clotting, so that the meal will not be interrupted. The saliva also contains pain killers. You usually don’t feel anything until a few minutes later when the pain killers wear off.

INSECT ADAPTATIONS Organisms have specialized structures and behaviors that help them survive and reproduce. Please complete questions 3-6 on pages 56 and 57 of your lab notebook with your group. While students are working, out transparencies 10, 11 and 12 up for a couple of minutes each for them to refer to.

ADAPTATIONS Discussion of questions 3-6. You will be studying the adaptations of a live insect. Relatives of this particular kind of insect have been on Earth for the past 400 million years, long before dinosaurs roamed the Earth. This organism has some highly effective adaptations that have allowed it to survive for that long. The insect we will be studying is the cockroach. Animals Around Us: Animal Adaptations: What Are They?

Investigation 9 - Part 2 Cockroaches

COCKROACHES Today we are going to get acquainted with the cockroach to increase our knowledge of insects. I want you to make as many observations as you can about the structure of the cockroach and its behavior.

COCKROACH HANDLING These roaches do not bite or carry diseases. They can be picked up by the sides of their thorax or abdomen and supported from underneath in your hand. It is okay for them to crawl on your hands and arms. Do not hold them more than a few centimeters above the table.

COCKROACH OBSERVATIONS Please open to page 61 of your lab notebook. Please complete this page. Remember: Don’t hurt the cockroaches Observe as carefully as you can Write down any additional questions about behaviors and structures of the roaches. See page 282

COCKROACH OBSERVATIONS Make some initial observations. Do you think that your roach is a male or female? Do you hear them making any noises?

COCKROACH SUMMARY How can you tell male cockroaches form female? Which roaches hiss and when do they hiss? Where do you find the cockroaches when they are resting? How do cockroaches respond to wind, water, smells and movement?

BREAKPOINT

COCKROACH INVESTIGATION We observed some structures and behaviors of cockroaches. These observations answered some of our questions about roaches, and raised some new questions. Today you will have the opportunity to work in your group to plan and conduct an in-depth investigation to answer one of those questions. The investigation should be conducted in three phases.

COCKROACH INVESTIGATION Review the questions on the Cockroaches sheet and the information on the Cockroaches Observations sheet. Talk in your group about a topic you would like to investigate in depth. Turn to page 62 of you lab notebook, Cockroach-Investigation Plan, and work together to plan your group’s investigation. Get the materials you need to conduct your investigation and a cockroach, and make the observations and record the data you need. Sample questions are on page 284 of the teacher guide.

COCKROACH INVESTIGATION Ask me to approve your experiment before you begin. Please record your results on page 63 of your lab notebook.

HOMEWORK Read Those Amazing Insects beginning on page 60 of the DOL textbook. Summarize each subsection of the reading piece in a 1 paragraph JS Model response.

Investigation 9 - Part 3 Cockroach Habitat

Those Amazing Insects DISCUSSION The article described some interesting bits of natural history about several insects. What was something interesting that you learned form the reading? What did you learn about the function of hissing? - All adult Madagascar hissing cockroaches hiss when disturbed or threatened. Males also hiss to establish their territory and to court a mate.

Those Amazing Insects DISCUSSION What would cause a whole colony of wasps to pursue you if you bothered them? Wasps release an alarm pheromone, which signals the whole colony to attack. Ants and aphids work together sometimes. What is the benefit to both? Food for the ants and protection from predators for aphids.

ROACH EXPERIMENT RESULTS Each group should share their question, procedure, results and conclusions. I will record the class information on the board. Look at this list of information we have about hissing cockroaches. Does this information suggest anything about how cockroaches live in their natural environment? Talk to your group about the kind of environment you think the cockroach could survive in.

Insect Mysteries Lab Notebook pages 64 and 65 Let’s complete the first two questions as a class. For questions 3-5 it is not important that you know what kinds of insects are being described. Your challenge is to look at the characteristics of animals and try to determine their habitat. Explain your evidence.

Insect Mysteries Lab Notebook pages 64 and 65 Question 6 is important. Use information you have obtained from working directly with the insects and the reading to imagine the hissing cockroach in its natural habitat. Describe in detail the habitat you see and what the cockroach is doing there. Explain why you visualized the habitat as you saw it.

Interconnectivity Every organism on Earth has a fascinating story to tell, if we take time to learn about it. Every organism has adaptations that make it possible for the organism to do its jobs- survive and reproduce in its environment. Most organisms have not been studied well enough for us to totally understand what their job is. But the more scientists learn about any organism they study, the more they find out that it plays an essential role in its environment.

CONNECTEDNESS Each organism depends on other organisms for its survival, and other organisms depend on it. If one type of organism dies off for some reason, all the other living things in its habitat are affected.