How You re Different From a Pigeon

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Marjory Russell
5 years ago
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Meet Manny. How You re Different From a Pigeon Name: Manny a.k.

larvae, and sidewalk leftovers Biggest Fear: traffic Meet Jan.

sticks, granola, and bananas Biggest Fear: pigeon paintball

1 Meet Manny. How You re Different From a Pigeon Name: Manny a.k.a.: pigeon, bird, flying rat, nuisance Diet: seeds, insects, larvae, and sidewalk leftovers Biggest Fear: traffic Meet Jan. Name: Jan a.k.a.: human being, girl, Janet, Jan-Jan Diet: fish sticks, granola, and bananas Biggest Fear: pigeon paintball 2008 Scholastic Canada Ltd. V001 How You re Different From a Pigeon 1/6

2 Believe it or not, you have a lot in common with both Manny and Jan. You eat food and digest it. And after eating and digesting, you have waste to clean up. There are two main kinds of waste: Leftover bits of food and other stuff that your body can t digest or needs to get rid of. This is handled by your digestive system. The waste products of all the work your body does. Some of this is handled by your blood and kidneys, which are an important part of your excretory system. Whatever the waste, it has to go, or it can become toxic. If you don t excrete your waste, you ll get sick. And when it comes to excretion, you and Jan are a lot different from Manny! How You re Different From a Pigeon 2/6

Manny: When grooming his feathers and grazing the sidewalk gets boring, Manny flies high above the city, using cars, lampposts, and even people for paintball practice. His paint?

3 Manny: When grooming his feathers and grazing the sidewalk gets boring, Manny flies high above the city, using cars, lampposts, and even people for paintball practice. His paint? Excretions from his body a.k.a., bird poop! Gross, you say? Not at all! Manny s excretory system is fascinating! Stomach and Other Stuff Digests food. At the end of digestion, Manny s blood carries nutrients throughout his body while leftovers get pushed out. Kidneys Here, teeny tiny little filters called nephrons (NEFF-ronz) remove waste from Manny s blood. In mammals, the waste is stored for a while. Manny s body is designed to fly and he can t carry anything extra. So, his kidneys send the waste right out, in the form of lightweight uric acid. (That s what makes bird poop white!) Ureter Exit tunnel for waste from kidneys Cloaca Mammals have different exits for different waste products. Just one will do for Manny! How You re Different From a Pigeon 3/6

Jan has to excrete waste products, too. Luckily, she does not find humour in tricks like Manny s. (Poor Jan! As a city dweller, she has been a paintball victim more than once.

4 Jan has to excrete waste products, too. Luckily, she does not find humour in tricks like Manny s. (Poor Jan! As a city dweller, she has been a paintball victim more than once.) Jan s urinary system is one of the most important ways that her body rids itself of waste. Stomach and Other Stuff Food gets digested here. Jan s body uses what it needs, and the leftovers leave by their own exit. Bladder Gradually fills with urine from Jan s kidneys. When it s about halfway full, nerves inside send a message to her brain, telling her, Time to go! Renal Arteries Just like Manny s, Jan s blood needs a little cleanup after circulating nutrients throughout her body. It flows into her kidneys through Jan s renal arteries. Kidneys Jan has two, but she could survive with just one. Each is about 13 cm long and 8 cm wide. They work constantly, filtering from 4 to 6 L of blood 400 times a day! Ureters After Jan s nephrons have done their work, clean blood flows on and waste is combined with water and becomes urine. Tubes called ureters carry it to the bladder. Urethra The urethra connects the bladder to the outside of Jan s body. It s 2.5 to 5 cm long. If Jan were a boy, it would be about 20 cm long. How You re Different From a Pigeon 4/6

Fast Food Working Birds Because storing his food like storing urine would only weigh Manny down, he has a unique digestive system.

5 More about Manny, Jan, and Excretions No Sweat! Manny has a great ventilation system that s built right in or rather, on! His feathers help to keep him warm during the winter and cool during the summer. So he doesn t need to produce another famous excretion sweat! Fast Food Working Birds Because storing his food like storing urine would only weigh Manny down, he has a unique digestive system. It digests an entire meal and gets rid of the leftovers in about 3 hours. For a human being, it s about 24 hours from start to finish. Nowadays people tend to think pigeons are a real pain. But before there was Internet, telephone, or even mail service, pigeons were very useful to human beings. Homing pigeons were used as a way to send messages longdistance. A homing pigeon can fly up to 145 km/h. That would break the speed limit on Canadian highways! How You re Different From a Pigeon 5/6

6 Body Balance The kidneys most important job is homeostasis: balance in the body. One thing that has to be balanced is fluids and minerals. On a sunny summer day when Jan is out skateboarding, she gets hot. Her body squirts out sweat through millions and millions of microscopic sweat glands. Jan s sweat is made up of mostly water with a little bit of salt, but it also contains urea the same chemical found in Jan s urine! Reduce, Reuse, Recycle In olden days, urine wasn t flushed away so quickly. It was saved in pots and used in the laundry to remove grease stains. Weavers used old urine to make stronger, thicker woollen cloth, and dyers used it to set colours more firmly. How You re Different From a Pigeon 6/6

Name Class Date. After you read this section, you should be able to answer these questions:

Name Class Date. After you read this section, you should be able to answer these questions: CHAPTER 14 4 Vertebrates SECTION Introduction to Animals BEFORE YOU READ After you read this section, you should be able to answer these questions: How are vertebrates different from invertebrates? How