Science: An Elementary Teacher’s Guide/Animals
It is not new to elementary teachers that kids have a natural curiosity about animals.
Dogs, cats, horses, and dinosaurs dominate many kid's attention and TV and the computer is a great source of information. It can be a challenge for teachers to keep up with all the information coming in, so they can help with interpretation and evaluation of the information. Outside a course or two, and maybe the same sources their students are exposed to, most teachers don't get a chance to learn enough to stay ahead of their kids' knowledge.
It's also possible to leverage students' interest in animals to provide instruction in other subjects like language and mathematics.
One possible way to spark interest is to know that about 2 million animal species have been described by science, but there may be another 25 million or more to discover. Scientists describe around 18,000 new species of animals and plants each year. Students love learning about animals, so this is an excellent way to grasp their attention.
Classification of Animals
There are billions of individuals, and maybe 30,000,000 kinds (species) of organism (living things) on Earth.
Biologists study organisms, and have come up with ways to name and classify them according to their similarities and differences. This classification system acts like a library catalog, allowing new information to be placed where it's most useful to future investigation.
The system in use by scientists today puts all living things into seven groups (called taxa, singular: taxon). The seven groups are arranged from the most general to the most specific. The taxa are, in order: Kingdom, Phylum (pl. Phyla), Class, Order, Family, Genus (pl. Genera), and Species.
The groups nest like cups. Any kind of organism belongs to only one species. Several species may belong to one genus, several general to one family, several family to one order, and so on.
- Kingdom: is the second-highest taxonomic rank below domain. Kingdoms are divided into smaller groups called phyla.
- Phylum: Is the term for the largest generally accepted groupings of animals and other living things with certain evolutionary traits. The animals we are familiar with usually fall into one of five different phyla which are Cnidaria (jellies and anemones), Chordata (including vertebrates), Arthropods (like insects, spiders, and crabs), Molluscs (snails, clams, & octopuses), and Echinoderms (sea stars and urchins).
- Class: The phylum group is divided into classes. The Chordata, (vertebrates) phylum splits into Mammalia, Actinopteryggi, Chondrichthyes, Aves, Amphibia, and Reptilia.
- Order: The Class group is now divided into small groups, known as orders. The class Mammalia, splits into different groups including Carnivora, Primate, Artidactyla, and Rodentia.
- Family: The various families of animals have similar features. The Carnivora order splits into families that include Felidae (Cats), Canidae (Dogs), Ursidae (Bears), and Mustelidae (Weasels).
- Genus: Every animal family is then divided into small groups known as genus (plural, genera). It contains animals that have similar features and are closely related.
- Species: The smallest group is species. A species consists of all the animals that fall under the same type, who breed to create young that are of the same kind. For example, while any two great white sharks are in the same species, as are any two makos, great whites and makos are in different species (since they can't interbreed). Other examples of species are dogs, cats, chickens, and humans.
Because life is messy and doesn't follow the rules we may like, many of these taxonomic levels, there are groups in between - the most common are given "sub" or "super" prefixes. For instance the subphylum Vertebrata is the group within the Phylum Chordata that include the animals with backbones (that includes us).
The scientific naming of organisms is called Taxonomy. All living organisms are given a binomial (two part name). The first word in the name is the genus, and the second name indicates the specific species. The names are always written as one, and are either in italics or underlined. Without the genus, the specific epithet (the species part of the name), the name is useless because many different kinds of organisms may have that same name, but no other organism has the same pair, genus and species, name.
An example of a species binomial name is Panthera leo. That refers to the lion, and only the lion.
The name can also show the relationships of animals. For instance without knowing anything else, you can tell that Panthera tigris is a close relative of the lion because it shares the genus Panthera. By knowing that, it is presumable that scientific name belongs to the tiger.
All living organisms are placed into kingdoms. There are six kingdoms, which are Animals, Plants, Fungi, Bacteria and Protists, and Chromists.
A Sample Classification
The lion belongs to the following groups:
- Kingdom Animalia (includes all animals)
- Phylum Chordata (includes all vertebrate animals, as well as some other more primitive ones)
- Class Mammalia (includes all mammals)
- Order Carnivora (includes carnivorous mammals, from bears to raccoons to harbor seals)
- Family Felidae (includes all cats)
- Genus Panthera (includes the great roaring cats: lions, tigers, jaguars, and leopards)
- Species leo (lions)
All animals belong to the kingdom Animalia, which simply means animals. All members of that kingdom have similar characteristics. While it might share some of those characteristics with other groups (kingdoms), the whole combined are unique to that kingdom. This is true of any level of taxon.
In the case of Kingdom Animalia, animals are multicellular (have more than one cell in their body), eukaryotic (those cells have a nucleus) organisms. Animals are motile, meaning they can move independently (without needing wind or waves), at some point in their life (some may not have this ability all their lives). Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis (body change) at some point in their lives.
All animals are heterotrophs: they must feed on organic material from other organisms for sustenance.
Vertebrates and Invertebrates
For general purposes animals are classified into two major groups: vertebrates and invertebrates. Animals with backbones and a spinal cord are vertebrates which includes fish, amphibians, reptiles, birds, and mammals. All animals without backbones or spinal cord are invertebrates. The invertebrates include spiders, insects, sea anemones, earthworms, and many others. There are many more kinds of invertebrate than there are vertebrate animals.
Vertebrates /ˈvɜːrtᵻbrᵻts/ (animals with backbones) are within the subphylum Vertebrata /-ɑː/ of the Phylum Chordata.
Vertebrates represent the overwhelming majority of chordates, with currently about 40,000 species described, but still only 4% of all living species described. Vertebrates include the jawless fishes and the jawed vertebrates. The jawed vertebrates include the cartilaginous fish (sharks and rays) and the bony fish.
The tetrapods (the animals with four limbs) are technically group of bony fishes, because they evolved from fishes. The tetrapods, which is an informal group, are divided into four living groups: amphibians, reptiles, birds, and mammals. Extant (living) vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm (0.30 in), to the blue whale, at up to 33 m (108 ft) which is the largest animal ever to have lived.
Here is a video link which explains the classification of vertebrates and invertebrates: https://www.youtube.com/watch?v=wd-QnKlfZHI
Mammals have been an important source of food for humans. Their skins have been used for making clothing and other body parts have been used in the making of tools and ornaments. They have hair or fur on their body that is used to maintain a certain amount of body heat. Some have a well developed brain for survival.
All mammals have mammary glands. These are specialized glands that produce a substance (milk) that feeds their young.
One characteristic of mammals is that most of them give live birth to their young and help care for them from the very start.
In most familiar mammals (the placental mammals) the embryo grows in a protective sack called the embryonic sac, which is attached to the mother's uterus. The nutrients flow to the developing baby from the placenta through the umbilical cord. The baby's waste is also transferred by this same cord, then disposed of by the mother's body. All mammals feed their young on milk produced by their mothers.
Marsupials (opossums, kangaroos) don’t have a placenta to feed their growing embryo, and the babies are born in a very early stage of development and attach to their mother’s mammary gland to continue growing while feeding on milk.
Monotremes are mammals that lay eggs. When the babies hatch, they still feed on milk. The platypus and echidna are monotremes.
Mammals are warm-blooded (endothermic), which means that they maintain their own body temperature independent of environmental temperature. If normal temperature is not maintained, then death occurs.
Mammals are vertebrates that possess of a neo-cortex, hair, three middle ear bones, and mammary glands. The mammalian brain regulates body temperature and the circulatory system, including the four-chambered heart. The life spans of mammals range from less than a year (some mice), to approximately 60 years which is the case for elephants. And sometimes over 100 years for humans.
Some mammals migrate at different seasons of the year. Other mammals ignore the cool months and hibernate or semi-hibernate. Mammals such as bears and skunks eat a massive amount of food compared to percentage of body weight in order to build up fat. This stored up fat will be used up during the winter months the animals will sleep. In order to not use too much energy, they will slow down heart rates, body temperature and even control their breathing by slowing it down.
Mammals play a vital role for the ecosystem in which they live. Mammals are important for maintaining services and functions associated with sustaining a balanced ecosystem.
Various mammals are used as a food and clothing resource. They are also important for recreational purposes.
Mammals can be found almost everywhere, from the Arctic, the Antarctic, the tropics, deserts, and forests. There are mammals that can fly to mammals that can swim: bats, whales, etc. Mammals are mobile and adapt quickly to environmental changes. They are able to move to new new locations as food supplies and other environmental conditions change. Mammals are known to migrate, which means, the process of an animal moving from one region or habitat to another, especially regularly according to the seasons. For example, the Monarch Butterfly migrates from Canada to Mexico. Elks are also known to migrate from the high mountains in the summer to lower elevations during the colder seasons. While some mammals migrate, others like bears are mammals that hibernate during the season changes. Hibernation is a state of inactivity and metabolic depression in endotherms. During hibernation, the mammals heart rate slows, body temperature drops, and breathing rate decreases. Animals in true hibernation can not be awakened.
CLASS Gnathostomata (jawed fish)
It is estimated that pisces, commonly called fish lived on Earth for 500 million years. A fish is any member of a paraphyletic group of organisms that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups. Most fish are ectothermic, allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like the white shark and tuna can hold a higher core temperature. Fish are abundant in most bodies of water. The largest fish is the whale shark, it can grown to be over 40 feet long and weigh up to or more than 41,000 pounds. The smallest fish discovered in the recent decade is the paedocypris which is only .31 inches in length for the male and a female can be a little under twice as big.
Amphibians typically start out as larvae living in water, but some species have developed behavioral adaptations to bypass this. The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin.
Amphibians are ectothermic (cold-blooded) vertebrates, which means they have a backbone, they live part of their lives in water, mainly during the larvae and birthing stage, and then part on land after they undergo the metamorphosis.
Amphibians have glands that produce a thick and slimy mucus that covers their skin to provide moisture and protections while they live on land. Adult toads live on land and return to the water only to lay eggs. Their skin is mostly covered with wart-like bumps. On the other hand, adult frogs and some types of salamanders are well adapted to both land and water. On land they breathe with their lungs. In the water, oxygen that is diffused in the water is absorbed through their skin.
Common amphibians are: frogs, toads, and salamanders.
Reptiles are a group (Reptilia) of tetrapod animals comprising today's turtles, crocodilians, snakes, lizards, and their extinct relatives. Reptiles have dry, scaly skin and are cold-blooded vertebrates. The skin of reptiles shed as they increase in size, they also have claws on their toes. Most reptiles are harmless unless they feel in danger or hungry. Millions of homes have some form of a reptile as a pet in their homes such as turtles, snakes or lizards. Some reptiles lay eggs which are then incubated in the sun and soil, some the young are born alive.
ORDER Testudinata (Turtle)
Turtles are best known for their distinguish feature which is there shell. They have upper and lower shells, with their body in between, and the ability to pull their head, tail, and legs into the shell. Turtles have various features such as a bony jaw which forms a sharp beak (no teeth), short legs, and slow movement.
Turtles have lived on land which are often called tortoises, some live in saltwater which are called terrapins, and some live in seawater. They grow up to eight feet long and weigh up to 1,000 pounds.
Lizards usually have feet and external ears, while snakes do not share these characteristics. However, because they are defined negatively as excluding snakes, lizards have no unique distinguishing characteristic as a group. Lizards and snakes have a movable quadrate bone, distinguishing them from the sphenodonts, which have more primitive and solid diapsid skulls. Many lizards can detach their tails to escape from predators, an act called autotomy. Lizards have small heads, long bodies and long tails. Since there are so many species of lizard, it's understandable that they come in a large variety of sizes. The largest lizard is the Komodo dragon of the Dutch East Indies, which grows to about 4.5 meters in length and can weight close to 115 kilograms. The smallest lizard is the tiny dwarf gecko, which grows to 1.6 centimeters long and weighs .0042 ounces.
Lizards are all over the world. Some live in trees, others prefer to live in vegetation on the ground, while others live in deserts among rocks. For example, the Texas Horned Lizard is found in the warm areas with little plant cover in southern North America. The Northern Fence Lizard, on the other hand, likes to live in cool pine forests in northern North America.
Most lizards are active during the day. Lizards are cold-blooded animals, which means they rely on their environment to help warm their bodies. They use the heat of the sun to raise their body temperatures and are active when their bodies are warm. The sun also helps lizards produce vitamin D. Their days are spent sun-bathing on rocks, hunting for food or waiting for food to come their way.
Some lizards are territorial, while others can easily live with dozens of other lizards of many different species.
Many lizards are carnivores. A typical diet for a lizard is ants, spiders, termites, cicadas, small mammals and even other lizards. Other lizards are omnivores, which means they eat vegetation and meat. These lizards like fruit, leaves and vegetables. Some lizards are herbivores and only eat plants. Iguanas and spiny-tailed agamids also eat plants.
There are over 20 species of crocodilians, which all live in or near water, the best known are alligators or crocodiles. They live in tropical areas and have been haunted for their skins. They have a long, low lizard-shaped body, and a long snout with strong jaws and sharp teeth. These types of reptiles have short legs, webbed hind feet, and a long powerful tail with which they swim.
Although alligators and crocodiles look alike, there are a few characteristics by which they can easily be distinguished. The alligator snout is broadly rounded, whereas a crocodile is narrower and more pointed. The alligator is heavier than the crocodile. the alligator is slower and less aggressive than a crocodile.
Suborder Serpentes (Snake)
Snakes do not have legs, ear openings, and eyelids which means that their sight and hearing are not so good. Snakes have a transparent scale that helps protect their eyes. Snakes can still move around but instead of using their eyes or ears they use their nostrils. They smell by using the Jacobson's organ as well. Snakes are also well known to use their tongues which are excellent for picking up scent particles that are around the air. When a snake uses its tongue, the air particles go into their Jacobson's organ which send signals to the brain to determine the smell. Since snakes do not have legs, they move their bodies from side to side in a winding motion in order to move. They use scutes which is the boread scales that are underneath their body. If a snake looks similar to a caterpillar it is due to the fact that they are using their scutes but they are moving slowly.
Snakes are carnivores which means they eat meat, they mostly eat rodents or small animals. They are known to swallow their meal whole, by using their flexible jaws with a detachable hinge that helps a snake swallow a body that is larger then the snake itself. Even though snakes do have teeth, they are not used for chewing their food. Their teeth help by taking a hold on their food making it easier for them to move their food down their throat. There are some snakes that are poisonous which help them by killing their pray but others choose to choke their pray. Venomous snakes have hollow fangs. When they strike, poison is squeezed from their venom glands into the hollow fangs passing the venom into the prey or victim.
Birds are a group of endothermic vertebrates. The most obvious difference between all other animals and birds is that they have feathers. Birds do not possess teeth, but have a beak and feathers. They are warm blooded, and generally fly, but so do other animals but what separates them from bats is the fact that they have feathers. There are few exceptions like an ostrich, kiwi and penguin. Ostriches can run quickly, while Emperor Penguins can swim well. The reason they are able to fly is that their body is sleek and their wings are able to have a lot of body surface compared to their light weight. Many birds eat their own weight in food per day because of the high amount of energy it takes flying. Birds can be found flying in the sky, up in a tree, on the water and some can even swim under water. The smallest bird is the bee hummingbird which is only about 2 inches long and weighs 1/10 ounces. The largest is the African ostrich, which may reach up to 8 feet tall and weighs more than 300 pounds. Not only can ostriches not fly, they are also the fastest bird on land reaching up to 40 miles per hour. The fastest diver is the peregrine falcon, which swoops down on its prey at 200 miles per hour. The highest flying bird is the bar-headed goose, they have been seen flying at over 25,000 feet in the Himalayas. Birds preen their feathers to strengthen them. The purpose for this is for waterproofing and reducing air resistance as they fly. They use their bill to press a drop of oil from a gland in their tail and spread the oil onto the feathers.
Beaks and feet are designed for specialized functions with an extensive diversity from one bird to another. A duck has webbed feet useful for swimming and a spoon shaped beak for scooping plants and small fish in the water. Some beaks are better suitable for cracking seeds or tearing flesh apart. Other birds have talons to capture small animals and be able to perch on trees and branches without falling off.
An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages (paired appendages). Arthropods form the phylum Arthropoda, and include the insects, arachnids, myriapods, and crustaceans. Arthropods are characterized by their jointed limbs and cuticle made of chitin. The rigid cuticle inhibits growth, so arthropods replace it periodically by molting. Arthropods range from lobsters and shrimp to spiders, millipedes, and insects. Arthropoda is the most diverse animal phylum, especially since it includes insects (which account for the vast majority of animal species in the world). However, it is only one of several phyla of invertebrates. Other invertebrate phyla include Annelids (segmented worms), Molluscs (snails, slugs, octopus and squid), Cnidarians (jellyfish), Echinoderms (star fish), and many more.
Insects are animals with six legs. They have a hard outer shell that's called an exoskeleton, which provides support and protection. Exoskeleton means "outside skeleton", many animals without backbones have these. Insects are the largest group of animals that have an exoskeleton. Insects have three parts (head, thorax, and abdomen).
All spiders are predatory eight-legged creatures that have organs to spin silk at the back ends of their bodies. They are the largest part of the Arachnid family, a group that also includes scorpions and ticks. Spiders all have the ability to bite with venom-injecting fangs to kill prey and nearly all of them are poisonous (even if it's just a little).
There are about 30,000 types of spiders in the world, living on every continent except Antarctica. And they're not newbies: fossilized spiders have been found in Carboniferous rocks dating back 318 million years.
Spider anatomy Spiders have two body segments, the abdomen and the cephalothorax. The first, or front part, is the cephalothorax, which is formed by the fusing of the head and thorax. The cephalothorax contains the eyes, mouth and legs.
Crustaceans include animals such as lobsters, crabs, shrimp, and crayfish. Most of the 30,000 or so species of crustaceans live in saltwater. And some live in freshwater, and only a few in land. Like many other Arthropods, Crustaceans grow by shedding their exoskeleton. Smaller Crustaceans eat diatoms and other tiny food-producing plants. Many Crustaceans are consumed by krill, fish, and other larger aquatic animals.
Try this quick quiz and test what you have learned by reading this chapter!
Some insects and mammals migrate this is because of changes in food supplies and weather patterns from one season to another many birds spend their winters and summers in widely separated places. The migration of birds stands today as one of the most fascinating and least understood events in nature. Blue grouse have reverse migration they inhabit lowlands in the summer and move to the tops of mountain evergreen trees in the winter.
More than 200 million years birds have adapted well to the requirements of many different habitats and conditions in some unique characteristics.
Most insects go through a complete metamorphosis including egg, larva, pupa, and adult and the egg develops into a larva a worm caterpillar stage. A larva eats almost continuously and some have voracious appetites and goes into the pupa stage (for a moth this is called a cocoon for a butterfly, a chrysalis. A moth spins its cocoon of silk but the chrysalis of the butterfly is a case that forms and hardens around the caterpillar. An egg of grasshopper or cricket does not develop into a caterpillar but hatches as a nymph. The nymph resembles the adult except it has no wings and the body parts are out of proportion, the head appearing large for the body. And the nymphs of the dragonfly and damselfly differ more from the adult stage. The simplest pattern in the growth and development of insects occurs in only few wingless insects.
Adaptation implies a process of change over time often in response to shifting environmental conditions as weather or food supply. The migration of the Arctic tern, the elk, and other animals suggest seasonal adaptations as the heavier coats of furry animals in the autumn. Squirrels instinctively store nuts for the winter as one way of adapting to the hard times.
Adaptation refers to an organism's ability to adjust to an environment. Which means that every living organism is adapted. A fascinating perspective can be adaptation indicates a process of change over time, often in reaction to shifting environmental conditions, for example weather or food supply.
Camouflage is an example of an adaptation that allows some animals to blend into their surroundings. Color, patterns, and body shape are adaptations that help camouflage both predators and prey. For example, the stone flounder, a flatfish, lays on the ocean floor as it searches for prey. These fish tend to blend in with the gravel or sand found at the bottom of the sea to avoid predators. According to Charles Darwin's theory of evolution by natural selection, the organisms adapt to their environment to become better fitted to survive and pass their genes on to the next generation.