Bird Anatomy Lesson: A Middle School Biology Lesson
This is the 16th lesson in a series of 30 hands-on Christian lessons covering middle school biology. This lesson focuses on the amazing design of birds. Observe bird bones, dissect gizzards, compare feathers, and more. I used this plan while teaching a 55 minute middle school biology class. Each lesson plan includes homework assignments and a variety of hands-on activities to make each lesson engaging & memorable. Use these fun lessons with your classroom, homeschool, after-school program, or co-op!
1. Welcome everyone back from winter break & allow each student to share something they did or got during the break.
2. Today we'll be studying the class Aves.
- What do you think that means?
- Who has been to an aviary at the zoo? What was there? (birds)
- What traits do all living members of the class Aves have? (bipedal [2 legged], warm-blooded vertebrates with feathers, scaly legs, & wings)
- What do birds have that no other animals have? (feathers)
I have gotten quite a bit of my background information on this unit from this book. The author does a wonderful job pulling out interesting tidbits about birds (and other flying animals later in the book) and sharing how their features point to an amazing Designer. In addition to using the A Beka text, I am reading through this book at home with all of my children.
Lightweight Bones & Strong Muscles
3. Sketch a person & a bird. Sketch in a few bones. Let's compare the anatomy of birds and humans.
- Look at the bird skeleton picture in the book.
- How do you think bird bones compare to human or mammal bones?
- Bird bones are lightweight, usually hollow, & strengthened by cross bracing like steel girders. Why? Reduce weight + Increase strength = Fly
- Flightless birds, however, have solid bones.
4. Pass around cleaned bones from a bird. If you have a steak bone, pass that around for comparison.
- What do you notice about them? (They're very light)
- Break them open. What do you notice? (They're almost completely hollow with a spongy-looking inside. They're also pretty strong for being so light.)
You will need:
- cleaned bird bones (such as ones from a Thanksgiving turkey or from a fried chicken meal)
- steak bone from a T-bone steak or soup bone (optional)
- magnifying glasses (optional)
5. Do birds have a jawbone & teeth? (No, though some extinct birds did have teeth.) They have keratin beaks = reduce weight.
6. More important bones:
- Keel = very strong sternum with large ridge = powerful flight muscles
- Furcula = clavicles (collarbones fused together) = Also known as the wishbone (*Birds are only vertebrates with furcula)
- If you have wishbones saved from Thanksgiving meals, allow students to break them.
- Humerus (upper arm bone) is short = strong
- Human palms have several bones but birds have 1 bone = reduce weight & increase strength
- Alula (retractable group of feathers on front of wing) & finger bones support feathers on wing tips
You will need:
- wishbones (optional)
7. Strength to Fly: What's the most important muscle on a bird? Who likes all that tasty chicken breast meat?
- Look at the bird muscles picture in the book.
- The most important muscles for birds are the pectorals (chest) = 33% of body weight of some birds
- Human pecs pull arms forward & back muscles pull arms toward back BUT bird pecs do both: raising & lowering wings like a rope & pulley
Constant Air Supply
8. Why do we need our lungs?
- Who has ever felt a hot bird sweating? Who has seen a bird panting after a hard flight? You haven't. Why not? Most of the air that enters a bird isn't used for breathing. Instead, it cools down the bird’s insides because all that flying creates a lot of heat just like what happens when you run a mile.
- Who has climbed a tall mountain? What is there less of up there? (oxygen) Was it hard to breathe? Birds need lots of oxygen at high altitudes where air is thin (sometimes up to 30,000 feet at which all other animals would suffocate)
- More complex respiratory system than we have. They don't have a diaphragm. Air is pumped through lungs as the chest muscles expand & contract.
- They don't have alveoli. They have tiny tubes (air capillaries), which allow air to flow through lungs, not just in & out.
- Those air tubes connect to air sacs to hollow cavities of bones to cool off the bird. The air actually flows in & out of its skeleton.
- The air sacs make the bird lighter, helping it float in air or water.
- They inhale & exhale twice = extract most oxygen from air
9. Heart. Like people and mammals, birds have a four-chambered heart that works in a similar manner. It pumps blood very quickly through a bird’s body to cope with the hard work of flying. The veins and arteries that supply blood to the wing muscles are especially large, since the body parts that are used for flying work the hardest.
-Flight requires lots of food & oxygen, delivered by strong blood supply = heart is larger in size proportionally than a mammal or human’s heart.
11. Discuss the digestive system for birds:
- Flying requires lots of energy = lots of calories = Might eat body weight in food each day
- Digest rapidly. They don’t store much solid or liquid waste because would add weight. Who's seen bird poop? It's more liquid than solid, isn't it? That's because it's passing through quickly.
- 2 important parts we don't have: crop & gizzard
- CROP - storage sac in esophagus - moistens food & releases it in steam stream to digestive system
- Do birds have teeth? How do they grind up their food? God gave them a GIZZARD. It's in the stomach & grinds food to make it more easily absorbed in intestine. Yes, they only have 1 intestine (not 2 like us & mammals)
- Sometimes birds swallow gritty material like sand or gravel to help with grinding.
12. Allow students to dissect chicken gizzards.
- Cut it open and let students feel how tough the inner lining is.
- Note: Dissecting a gizzard isn't too exciting as there is not much to see, but my students enjoyed dissecting it nonetheless.
- If anyone is wondering, my students who have eaten chicken gizzards said they taste like liver (not at all like chicken) and are very tasty. I sent home the leftovers with a student to use for fishing as they make great bait.
YOU WILL NEED:
- gizzard for each group of 4-5 students (Turkey or chicken gizzards can be bought from the grocery story alone or in a package inside a whole cooking bird.)
- Disposable hard plastic plate or dissection plate for each group
- scissors and/or knife for each group
- disposable gloves
13. Discuss the sense of sight for birds.
- They have the best eyesight of all of God’s creations. Eagles can see a crouching hare a mile away. Some owls can see in dim moonlight as well as you can in the day.
- Their eyes are huge compared to their heads. God designed their brains to be positioned further back in in their skull & tilted to make more room for their eyes.
- Have you noticed that birds have to turn their heads to look at an object? That is because their eyes aren’t able to move very much. Keep your head still but move your eyes around in a circle. Birds can't do that. They have limited mobility of their eyes, so God gave them very flexible necks. Owls can move their heads 180 degrees without moving their bodies.
- Monocular vision: Some birds have eyes on the sides of their heads to detect danger. Do all birds have monocular vision. (No)
- Which birds have binocular vision, meaning both eyes are in the front? (Birds of prey & other birds that are predatory) They have a narrower field of vision but keener at long range & improved depth perception
- Have the students stand up at their seats, close their right eye, and try to toss around 1-3 tennis balls. How did only using 1 eye affect your ability to catch the ball? (It affects your depth perception.) Why do you think God gave predatory birds binocular vision?
Birds do have amazing eyesight. They can see a greater range of the color spectrum than we can and some can focus on two different objects out of each eye. Each of their eyes has 2 foveae (the part of the retina which “sees” most clearly).
YOU WILL NEED:
- at least 1 tennis ball
14. Can birds hear well? Yes, they have very sharp hearing. Owls can hunt rodents hidden under leaves simply by sound. Cave swiftlets use something like echolocation in dark caves.
15. What about the sense of smell? Can birds smell? Some birds seem to lack it while others have keen sense like vultures and other birds that feed on carrion (dead animals).
16. Examine & compare feathers.
- What is unique only to birds? (feathers)
- How do feathers help birds? (allow to fly, insulate, protect, form shape [smooth & streamlined]
- How many feathers do you think birds have? (up to 3000 feathers)
- Pass out various feathers. What do you notice about them?
- Compare contour and down feathers. Point out the rachis, shaft/quill, vane, barb, & barbules. If possible, compare the feathers of a hen and rooster.
The contour feathers are strong and found all over the bird. They point toward the tail to aid in streamlining. Some contour feathers are flight feathers which provide the wing shape for flight.
- Down feathers provide insulation. How do they feel? (soft & fluffy) Are they heavy? (No, they provide insulation without significant weight). Do you know what temperature our bodies maintain? (98.6 degrees Fahrenheit.) The insulation feathers help maintain a body temperature for birds of 110 degrees Fahrenheit -- even when they are in really cold temperatures.
- The shaft is like the backbone with thousands of bards zipped by tiny hooks called barbules.
- Look at the feathers with magnifying glasses. What do you notice?
- Open an umbrella. If you carry an umbrella on a windy day, which catches more wind: the under or top side? Why is this? Does the curved surface of the wing act the same way? Look at a wing feather. Are the barbs as long on one side of the quill as on the other? Do they lie at the same angle from the quill on both sides? If not, why?
- Which side of the quill lies on the outer side and which is on the inner side of the wing? Is the quill of the feather curved?
- Press a tip of the quill against your hand. Which way does it bend more easily, toward the convex or concave side? What has this to do with the flight of the bird? If the bird flies by pressing the wings against the air on the down stroke, why does it not push itself downward with its wings on the upstroke?
- What is the shape and arrangement of the feathers which prevents pushing the bird back to earth when it lifts it wings?
- Why do you have a rudder on a boat? Do you think a bird could sail through the air without something to steer with? What is the bird's rudder?
- Does a hen when she flies keep her tail closed or open like a fan?
- Compare a tail feather with a wing feather and describe the difference. (These questions are from "Handbook of Nature Study.")
You will need:
- a variety of feathers: contour feathers, down feathers, tail feathers, wing feathers, hen feathers, rooster feathers
- an umbrella
- magnifying glasses
17. Discuss preening.
- Ask who has seen birds clean themselves. Feathers protect birds' skin and keep them warm, so they have to take care of them. Birds clean their feathers by preening.
- Who knows how many neck bones we have. (7) To help preen, God gave most birds 13-25 neck vertebrae, more than any other animal.
- They run each feather through their beak which straightens the feathers kind of like when you have to straighten and clean the Velcro. The barbs and barbules fit together like Velcro. Run your fingers across the feather and try to separate the barbs and barbules. Now rub your finger over it and try to have them fit back together.
- Another thing they do when they preen is to coat their feathers with a light layer of oil from their oil or uropygial gland (at the base of their rump above their tail). This is especially helpful for water birds. The oil keeps the feathers dry and light. Sometimes you can see birds preening, similar to a cat or dog licking their fur.
- Pour a little bit of water on a paper towel. What happens? The paper towel gets soaked. What would happen if that happened to a bird when it was flying? (It wouldn't be able to fly.) What do you think will happen when we pour water on contour feathers? [Allow students to work in groups to pour a little water over the feather. Have paper towels under them.] What happened? (It just slid right off and doesn't even feel wet.)
- That's not all that the oil gland does. The oil also inhibits the growth of bacteria and fungus, contains a Vitamin D precursor that changes into Vitamin D, and preserves the protein (keratin) in the feathers.
You will need:
- Velcro (we used the velcro straps on backpacks) (optional)
- contour feathers for each group of 3-5 students
- paper towels
The Birds of the Air
18. In Matthew 6:26 Jesus said, "Look at the birds of the air; they do not sow or reap or store away in barns, and yet your heavenly Father feeds them. Are you not much more valuable than they?"
- Do birds seem to worry quite a bit? (No) Why not? (God takes care of them & provides for them.) Who provides for them? (God) Does God also provide for you? (Yes)
- When you notice birds, take the time to thank God for providing for you and also remember that He does care for you and is taking care of you.
Page numbers refer to the pages in A Beka's Science: Order & Design.
- Friday: Complete your Bird Log by identifying 10 birds outside. (You can do this throughout the week. You must identify & sketch 10 different birds. You’ll get extra credit for filling out the log completely.)
- Monday: Read pp. 230-237 & answer 6 questions of your choice on p. 237.
- Tuesday: Read pp. 237-240 & answer 3 questions of your choice on p. 240.
- Wednesday: Read pp. 241-250 & answer 5 questions of your choice on p. 250.
- Extra Credit #1: Read the Bird Wing Tutorial and draw an anatomically correct set of wings (or even an entire bird) using the tips suggested in the tutorial.
- Extra Credit #2: Complete the Comparing a Human and Avian Skeleton worksheet (only coloring in the bones, not completing the fill-in-the-blank worksheet)
Looking for all my lessons?
(I'll be posting a new lesson each week.)
- First Day of Class & Plant Identifications
- Parts of a Flower
- Amazing Plants (Horticulturist Guest Speaker)
- Seeds and Flower Families
- Photosynthesis and Plant Parts
- Cardiovascular, Respiratory, & Digestive Systems
- Skeletal, Muscular, & Integumentary Systems
- Endocrine & Nervous Systems and Healthy Living
- Human Baby Fetal Development (Pregnancy Care Center Guest Speaker)
- Creation and Science
- Creation, Evolution, & the Eyes of Faith
- Classifying Plants & Animals
- Amazing Mammals
- Mammal Dissection
- Semester Review & Winter Party
- Bird Anatomy
- Bird Features
- My Middle School American History Lessons
- All of My Hands-on Lessons & Unit Studies
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