Chapter 3 4th Grade PDF

LEAP Chapter 3 Structure and Processes rffih of Organ isms Standards Covered: 4-PS4-2,4-LSr-1, 4-LSl-2 E...

LEAP Chapter 3 Structure and Processes rffih of Organ isms Standards Covered: 4-PS4-2,4-LSr-1, 4-LSl-2 Essential Questions: o Whatrole has adaptation played in animals developing internal andexternal structures? o How has animal eye development helped in survival? o How have plants adapted to ensure survival? o How have animal behaviors helpedsurvival? Animal Structures and Processes To eat, survive, and reproduce, animals have developed advanced senses. They use their senses to process information about their environment. These structures work differently for each animal. ln this chapter, we look at how they work. Adaptation An adaptation is anything which helps an organism survive. Adaptations take a longtime to develop. Change in the appearance ofan organism happens over a very long period of time. For example, eagles have talons (claws) to catch fish. How did they getthese talons? A long time ago, birds started eating fish to survive. Fish are slippery. Birds needed sturdy feet and claws to catch and hold onto fish. Birds with the strongestfeet caught more fish than birds with weak feet. They lived a longtime, raising many ch ildren. Theirchildren had the feature ofstrongfeet. Overtime, the adaptation for strong feet, called talons, developed..*-- Adaptations for eating fish Adaptations for catching fish figurc 3.1 Eagle AdaPtqtions what happened to the fish-eating birds with weakfeet?They did not survive and did not have are the way ch ildren. Their traits were not pas-sed on to their offspring. Sometimes adaptations the way living things organisms look, or their external structures. Other times adaptations are Leiave (act) and their internal structures. For example, there is less food for bears in winter' Bears to develop the adaptation of if1"iioufa i.rt tf'rough the winter were more likely io live, causing bears hibernation. 48 Copyright o American Book ComPanY  Chapter 3 Structure and Processes of Organisms External Features Changes in habitatand evolution caused animals to adapt certain processes and external features. I I * I Let us look at some examples. Webbed feet, like on a duck, help the animal move through the water. The webbed feet also help ducks swim more quickly to catch prey. Sharp beaks, like the ones eagles have, are another external feature I I t' ::l{ giving animals an advantage. Sharp beaks make it easier to catch prey and eat it. Having a sharp beak helps the animal defend itself Animals which evolved wings gained multiple benefits. Feet Figurez.zWebbed Birds travel great distances because oftheir wings. They also can escape ground predators with their wings. There are some birds which can fly at speeds up to 6o miles per hour. Wings serve an added purpose for specific bird species. For penguins, their wings help them swim faster in water. Penguins have wings but cannot fly, so their wings had to adaptto different conditions. The coveringon an animals is another survival method and reproductive process. The environment impacted their evolution. Forexample, tigers living in thejungles developed stripes. The stripes hid them in the trees from their predators. Additionally, the stripes help them sneak up on other animals. The spots on leopards and cheetahs serve the same purpose. Some external structures are mainly to attract mates. A male peacock's feathers are brightly colored to attract female peacocks. The female peacocks, called peahens, do not have bright feathers. The peahens need the dull colored feathers to h ide and protect their nests. Body coverings are a survival feature, too. Scales protect fish and reptiles. The scales on alligators, crocodiles, and snakes defend them from harm. The scales also help them regulate body temperature. Didyou know some animals can change colors when they sense predators?There are species ofchameleons, fish, and frogs which can change colorto blend in with their surroundings. Animals are not the only ones who develop external structures. Plants are very adaptive to their environment. Plants develop brightly colored flowers to attract pollinators like bees, figure 3-3 Peacoch hummingbirds, and butterflies. Pollinators visit flowers and move the pollen to other flowers. lt is how flowers and plants reproduce. Many plants develop features to defend themselves, too. Thorns keep animals from eating plants. some piants give offbad smells to keep predators away. Copyright O American Book Company 49 Chapter 3 Structure and Processes of Organisms figure 3.4 Pollinotors All in the Eyes The evolution ofeyesight is one ofthe most beneficial features for animals. Light enters the eye and passes through. When light reflects offan obiect, the eyes receive information, Iike whether something is light or dark and what colors are present. Some animals rely on their eyesight more than others. Eagles rely heavily on their vision. Eagle eyes are exceptionally sharp. Eagles see fish in the waterfrom hundreds offeet above. Eagle eyes are 4 to 8 times stronger than a human eye. P 7. figure 3.5 Eagle eye Cats are also animals with exceptional eyesight. Cats see very well in the dark. Theireyes only need aboug5% of light a human would need to see an obiect. The cat's pupils control the amount.of light they receive. Th-eir excellent eyesight helps them see prey in the dark. Their eyes can also track fast- movingobjects betterthan humans. lt is why cats are so good at catching mice' e... f figurc 3.6 Cat eyes 50 Copyright o American Book ComPanY  Chapter 3 Structure and Processes of Organisms Prey animals also developed superior eyesight to help them survive. Their pupils are horizontal to give the animals a wide range of vision. Their eyes also rotate differently than the eyes ofotherspecies. They do not have to turn their heads to see. When deer eat grass, their eyes can look in different directions at the same time. Combined with their horizontal pupil, this adaptation allows them to detect predators more easily. Animal Behaviors Animals have developed diverse types of behaviors to survive and reproduce. These behaviors allowthem to thrive. One famous i instance ofadapted behavior is bird migration. Birds like geese fly from the cold, northern climates in the winterto the warmer climates of the south. Each year the birds make the journey south. Because of their migration, birds find food in winter. ln an earlier section, we mentioned bears hibernating. Bears hibernate to survive the winter. They eat an excess offood in the fall which F-= gives them energy throughout their hibernation. F Some behaviors are for huntin g and defense against predators. The predator-prey rycle causes many ofthese adaptations. Predators develop behaviors to catch more prey. )aguars hunt at night when many animals are asleep. They also do not roar like other large cats. This helps them stalk their prey. Some creatures ! set traps for their prey. Spiders weave webs to catch prey. The Figure 3.7Jaguar webs are sticky, which causes the prey to remain in the web. Prey developed behaviors to protect themselves, too. When a skun k is threatened, itwillspray a stinky chemical all overthe predator. Some animals will play dead to deter predators. An imals like the zebra will herd together for protection. A large group of an imals is harder to catch than a single animal. Many ofthe animals who live around people, like raccoons, opossums, bobcats, and foxes, are nocturnal. Nocturnal means are active at n ight. Because these an imals look for food at n ight, people do not see them very often. Being nocturnal is a behavioral adaptation. Some animals mimic other things. A mimic is something which looks like something else but isn't. The adaptation is called mimicry. Stick bugs mimic tree wvigs so predators who are looking for a tasty bug will think they are a plant. Some mimics look like other harmful animals to scare offpredators. The Scarlet Kingsnake also lives in the southeast. lt has black, red, and yellow stripes like the dangerous Coral Snake. But it is non-venomous. lt does not bite. Some butterfl ies have "eye spots" on their wings. These spots or markings look like the eyes of animals. Animals and insects also develop social behaviors. Social behaviors are good for mating and protection. Bees live in large colonies. Bees divide into groups and perform iobs in the hive. The queen rules over the other bees. The worker bees make the honeycombs, clean the hive, and watch outfor theyoung bees. Drone bees mate with the q ueen. Their social structure helps bees survive. Figure 3.8 Flamingos Copyright O American Book Company 5I Chapter 3 Structure and Processes of Organisms Some animals have adapted dancing as social behavior. Certain male species of animals dance to attract mates. For example, male flamingos will group together and dance. They will stretch their necks and their heads back and forth. Male Adelie pen guins will gather rocks and present them to the female. lf the female likes the male, she will use the rocks to line her nest. She will also make him her mate. The most successful an imals using these behaviors guarantee their species'survival. Plants also display behaviors. Some trees survive the winter by shedding (losing) their leaves. They are called deciduous trees. lf the leaves remained on the trees through the winter, they would freeze and die on the tree, and there would be no new leaves in the spring. Pine trees and other con ifers (evergreen trees with needles and cones) can also be found in the mountains. They do not need to shed their needles because the needles have a thick "skin" or waxy coating (called a cuticle) that helps to protect them from freezing. This adaptation helps conifers survive when it is windy and cold in the mountains. The cuticle also helps conifers live through drought (lack of rain). Some plants eat insects. Venus flytraps and Pitcher plants lure flies into their specialized leaves and then eat them. lnternal Structures The internal structures of plants and animals help them process the world. These structures also aid in survival, growth, and reproduction. The brains of animal species process the information they receive from othersenses. The brain lets animals know when they are in danger or ifsomething is not good to eat. Their sense of smell sends signals to the brain. Dogs recogn ize h umans and other an imals by smell. The "fight or fl ight" response happens when senses send danger signals to the brain. lf a gazelle senses a lion, its brain will tell itto run orfight. Different internal systems are working. The animal's heart beats faster. lts breathing becomes shallow. Although it mayseem like a slow process, it all happens very fast. Animals and humans have a circulatory system. The circulatory Blood Flow in Human Circulatory System system sends blood th roughout bloodflor^, to h.d and lrms the body through a network of veins and arteries. The heart pumps the blood through the body. Blood exchanges carbon pul dioxide for oxygen in the body. When the heart pumps faster,like when an animal is in danger, it T pumps more blood through the body. More blood means more oxygen for the animal to use for hcart fight or flight. aorta The digestive system moves =-,.-.t food through the stomach and blod fiov, !o dirrtir,. intestines. Food passes through a.-.t rycen rnd tmEr limbr the esophagus into the stomach where it digests. The remains are passed through the intestines and finally exit the body as waste. Some figurc3.1o Circuldtory swm animals have unique digestive down food systems. The cow has four stomachs for food to pass through. Each one further breaks before it is finally passed. Animals li ke pigs have one stomach for digestion. 52 Copyright o American Book ComPanY  Chapter 3 Structure and Processes of Organisms The digestive system of chickens is entirely different. Chickens store their food in a special organ called a crop. The crop then pushes the food into the stomach and gizzard. The gizzard breaks down the food. Animals draw energy from the food they eat. M/.as.d \ t, *,ffiifa '@gz3:o /=r,;z.- figure 3,tt Cow digestive system The respiratory system helps animals breathe. ln the animal kingdom, there are three types of respiratory systems. Animals use either lungs, gills, or an outside exchange system. Birds, mammals, and reptiles use lungs to breathe. Fish use gills, which are open ings on the sides ofthe fish. An integumentary or outside system is common on organisms like sponges and insects. There are openings in the body which filter gas and oxygen. Breathing is vital for bodily functions and an organism's survival. The intern al structures of plants are different from the internal structures ofanimals. Plants have two organ systems. There is the shoot system and the root system. The shoot system is above ground. The system includes the leaves, stems, flowers, and buds. The shoot system absorbs light and nutrients. The vascular system ofthe plant sends water and nutrients to the roots. The root system keeps the plant in the ground and absorbs nutrients. The roots also store nutrients. The nutrients help plants create Ftgure 3.tz seo spongs cells. Plants can sense environmental conditions. For example, a sunflower will tilt in the direction of the sun. Plants will also grow in the direction ofwater and sound. The theory Ftgwe ,.8 Shoots and rcots that plants grow betterwhenyou play music is not entirely a myth. Copyright O American Book Company 53 Chapter 3 Structure and Processes of Organisms Science Journal Objective: Learn how adaptations help animals survive. Notes: Perry the Penguin is goingon vacation to Africa. Research information about penguins (what they eat, where they live, how they survive). Data: Write a story about what Perry needs to pack to survive while in Africa. You can even make a postcard from Perry describing his trip. Summary: Now, write a similar story aboutyour favorite animal. Animal Sixth Sense ' Animals have adapted to have better senses than humans. Animals can smell, F,.-, t I hear, taste, touch, and see. Some ofthese senses are greater in some animals than in others. Dogs are a perfect example. Their noses are I oo,ooo times more powerful than the noses of humans. Dogs create odor profiles of people and other animals. They smell in 3D. Dogs are used to sniffout plants and -t other animals at airports. Dogs are also known to smell and detect certain diseases in humans. Hound dogs have the most powerful noses among dog breeds. Figure 3.r4 Beagle sniffingdeep pits bewveen the nose and the eye on pit vipers allow them to see in for food at airport The h uman eye. The pit viper sees infrared. lnfrared is Iight waves invisible to the this light spectrum at night. lts night vision determines the size and distance ofthe prey. This sixth sense makes it an excellent hunter. Have you heard of homing pigeons? These pigeons are expert navigators. They contain iron structures in their beaks. Like a com pass, the iron is attracted to the magnetic waves around the Earth. The homing pigeons, among other bird species, sense these magnetic waves. Their sense of direction is nearly perfect. Sharks can detect electric charges given offby other animals. The Hammerhead shark is extra sensitive to these waves. tt can find prey easily in the water. A shark can sense one drop of blood in the water and scent blood a quarter ofa mile away. Native to Europe and Asia is a species of fish called the Weatherfish. lt's known as the meteorologist ofthe sea. lt can detect high and low- pressure systems (wh ich cause weather). The air pressure affects the buoyancy of the water. This is whatthe fish senses. The fish swims more when a storm is coming as a warningto take cover. 54 Copyright o American Book ComPanY  Chapter 3 Structure and Processes of Organisms l'l& r€.-gllt*,]el9'*,5Cru $!B L ili.&.r'a !rrl.ID.r.) Ftgure 3,t s Hommerheod shorh Practice r: Animal Structures and Processes 1 Bees and butterfl ies are A predators. B pollinators. C prey. D drones. z. Christina sees a birddancingwith its feathers ruffled. What is the bird most likely doing? A fighting a predator B finding food C attracting a mate D sensing magnetic currents 3. A bug mimics a twigwhen itsits on a branch. Whatwould be the main reason it does this? A hiding from a predator B attracting a mate C finding food D fighting predators +. Which of the following is an example of an internal structure? A fur B lungs C scales D whiskers Copyright O American Book Company 55 Chapter 3 Structure and Processes of Organisms Chapter 3 Key Term Activity Fill in the blank with the correct word. Word Bank N octurnal lnternal Structures External Structures Predator-Prey cycle Adaptation 1 is what living things must do to survive. They develop z and 3. For example, a fish developed gills to breathe underwater. Cats developed eyes which can see in the dark. A large factor in animal changes isthe4.-.Tosurviveandcatchfood,livingthingshadtochangetheirbehavior. Manyanimalsbecame5'-sotheycouldcatchfoodatnight. Key terms are defined in the book's glossary. Answers to Key Term Activities are found in the Teacher's Cuide. Copyright @ American Book ComPanY 55  LEAP Chapter 4 Waves and Comm un ication ffih Standards Covered, 4-PS4-1 ,4-LSl-r, 4-LSr-z Esse ntial Questions.. what is the structure of waves? o How can waves move objects? A Wave in Motion You learned about ocean waves in previous chapters. With ocean waves, you can see the movement. Waves have the powerto shape and move objects. Waves are also used for communication. ln this chapter, we'll learn how waves move and how they are used to communicate. Object Movement and Waves Have you heard the phrase, "sound carries"? lt's true, itdoes. Waves carry sound. We learned amplitude is the maximum height of the waves. Amplitudes and waves shows changes in a wave during a single period of time. The top ofthe wave is called the crest. The lowest part ofthe wave is called the trough. You can see an ocean wave moving objects across the surface. Although invisible to the human eye, sound waves also have structure. Wavelength is the distance between the crests of repeating sound waves. Waves are very powerful. They have the power to move obiects. The amount of motion depends on the wavelength and amplitude moving it. crest Tranwerse wave (water wa ves) rough WAVC en Longitudinal wave (sound wa ves) compression expan don Figure 4.t Difference between wqves Copyright o American Book Company s7 Chapter 4 Waves and communication Below are examples of waves movingand changing objects. Sound waves are capable of moving obiects. They can pass through solids and liquids. A good example is the waves coming from speakers which cause certain liquids to move and form shapes. lf you put a bowl or glass of liquid on top of a speaker and turn on some music, the liquid moves in the container. The waves push the liquid upward. lfyou place a coin on top ofa speaker, the sound waves (vibrations) will move the coin across the surface. The louder the sound, the more the object moves. -a figure l.z Liquid in soundwaves Sound waves can also shatter obiects. The human voice can break a glass. Class has its own frequency by which it vibrates. Frequency is how often it vibrates over a certain amount of time. Opera singers who can hit a certain high note will vibrate the glass. When this happens, the glass shatters. The volume the singer reaches also increases the chance of the glass shattering. The h igher the volume, the more likely the glass will break. The type of glass also matters. 4 t, ,| ( ( fft:,, Ftgurc 4.3 sound shqttering glass Copyright o American Book ComPanY 58  Chapter4 Waves and communication Levitating objects in the air with waves is possible. lfyou have sound waves meeting together in one space, the object in the middle may levitate. lfyou have four speakers facing an obiect and turn on the sound, the object levitates. The soundwaves will hold the obiect in the air if it is light enough. l( It t\ ?, (t ), figure 4.4 Sound levitoting ofieds Science Journal Obtain a long slinky, Cet a friend to hold one end ofthe slinky on the floor about 5-ro feet away from you. While holding the other end ofthe slinky, repeatedly moveyour hand to the right and left along the floor to introduce a wave into the slin ky. Notice that the slin ky is moving left and rightwith the movement ofyour hand. However, the slin ky wave is traveling towardyour friend. what type of wave is this? Now, repeatedly move your hand holding the slin ky toward and away from your friend. Notice that both the slinky and the slin ky wave are moving towardyour friend. What type of wave is this? Practice r: A Wave in Motion I What is wavelength? A the middle point of the wave B the top ofthe wave C the horizontal distance between crests D the number of waves that pass a point in time Copyright O American Book Company 59 Chapter 4 Waves and communication 2. what causes a glass ofwater to move across the top ofthe speaker? A the vibrations B the length ofthe trough C the speed ofsound D the volume ofsound Esse ntia I Questions.. How do animals use waves to communicate?. How have animals developed structures to receive sound? Waves and Communication Animals using Waves Humans use a complex set oforgans to communicate. The sound waves forspoken words come from the throat. The tongue and teeth shape the sounds ofthe words. Humans are capable of making allsorts ofnoises. They each have a different meaning. The sound of laughing could mean something is funny. A shout can get someone's attention. Animals have developed a similarsystem to communicate. Although we want them to, animals can'ttalk like humans. Animals must rely on otherways to communicate. Many creatures in the animal kingdom rely on sound waves. Animals emit certain sounds to communicate. You are probably the most familiar with dogs, cats, and birds. Dogs bark and growl to communicate. Some barks are a friendly greeting, while others warn other animals away. Sound waves travel through the air. Other animals and humans pick up the sound. Cats meow, hiss, and purr to communicate. Purring is vibrations coming from the cat's th roat. Birds chirp and sing to communicate. Different sounds have various meanings. !- figurc 4.5 Dogstqlhing Copyright o American Book ComPanY 60  Chapter 4 Waves and communication Animals, fish, and insects have developed unique ways to /. H.S. communicate. Wolves call out to other wolves by howling. The howlingdraws the pack together or signals prey is nearby. A wolf's howl can be heard up to six miles away in a forest. Bats have an amazing system for communication. Bats mainly hunt "==r{ and fly in the dark. Although they have good eyesight, they use *l ! figure 4.e Wolf howling sound to locate and communicate. The system they use is called echolocation. The bat releases a sound wave which bounces off otherobiects. The batsenses the direction ofobiects from the return waves. The bat avoids obstacles and finds its prey quickly. Bats use the echoes to communicate with each other, too. Emitted \Alave of Bat Figure 4.7 Bdts' echolocdtion Dolphins have a similar method of communication using sound waves. Dolphins use two different types ofsounds to communicate' pulsed sounds and pure tones. The pulsed sounds are clicks. The clicks are used in echolocation. The clicks help the dolphin know what is in their environ ment. Pure tones are wh istles, ch irps, and screams. Scientists are still trying to understand the meanings of all the sounds. However, scientists do believe each dolphin has a unique whistle. 1 figure4.8 Oolphins Copyright o American Book Company 61 Chapter 4 Waves and communication You've probably heard a loud buzzing sound during the summer. ltwould be the song ofthe cicadas. Cicadas use a buzzing noise to communicate. The organ they use to make this sound is in their abdomen. The sound can reach over I zo decibels. Decibels are the measurement ofthe volume of sound. Sounds can damage human ears attzo decibels. Cicadas use the sound to find mates or tell other cicadas they are in their territory. Crickets use sounds for the same purpose. Mosquitoes use loud humming sounds to communicate. The sounds vibrate through the air. The sounds help animals interact with their environment and other creatures. Receiving lnformation Humans process sound with their ears and brains. lnside the human ear is a complex system oforgans. These organs process sound. The ear receives the sound and relays information about the sound to you. You hear a dog barking outside. Your ears receive the sound waves. The brain tells you that you hear a dog. Along with developing ways to talk, living things have developed ways to ) receive information. First and foremost, many animals developed ears. The human ear developed to receive a wide range ofsounds. Animal ears developed in ways to best ensure their survival. Rabbit ears grew large and tall to hear sounds from far away. Cat ears rotate 180 degrees to hear the softest ofsounds. The elephant's large, thin ears help it hear predators from Ft gwe 4.9 H ippo un d erwqtet long distances away. The hippopotamus' ears are high on top of its head. When a h ippopotamus goes underwater, it can still listen to sounds because of its ears. Not all creatures developed ears for hearing. They adapted for survival in other ways. Many creatures developed sense receptors. These are special organs developed to process information. Snakes, for exampte, don't have ears. lnstead, they can feel the vibrations ofother creatures with their bodies. There is a bone in the jaw which helps them "hear'the vibrations. Fish have organs called otoliths. Otoliths are inside the fish's body. They detectthe vibrations around them. lnsects have unique ways ofhearingsound as well. They do not have ears like mammals. Crickets hear sound through their knees. Mosq uitoes use the tiny antennae which cover their bodies to hear. The cicadas we nrentioned earlier use organs in their stomachs. These adaptations prove living things can use sound waves differentlY. Practice z: Waves and Communication r. Which type of communication do bats and dolphins rely on? A radar B vibrations C echolocation D water waves 2. How is sound measured? A liters B decibels C beats D amplitude 6L Copyright o American Book ComPanY  Chapter 4 Waves and communication Chapter 4 Key Term Activity Fill in the blan k with the correct word Word Bank Freq uency Echolocation Crest Trough Waves are used for many different purposes. However, it's important to know the structure ofwaves The top part of the wave is the r.. The lowest part of the wave is the z. Waves are measured by 3 Sound waves are some ofthe most powerful. They can move or shatter objects. People and other living th ings adapted ways to receive and use sound. Dolph ins and bats use 4 to locate objects near them. They also use itto communicate. Key terms are defined in the book's glossary. Answers to Key Term Activities are found in the Teacher's Cuide. Copyright O American Book Company 63