Animal Kingdom: Vertebrates and Invertebrates Lesson

The kingdom Animalia is represented by organisms that are mutlicellular, eukaryotic, heterotrophic and motile (they can move!) at some point during their lifetime. Animal cells do not have cell walls, as we discussed in an earlier unit.

Animals are further classified as invertebrates or vertebrates. Invertebrates, which make up 90% of the animals on Earth, lack a backbone. Examples of invertebrates include jellyfish, sponges, insects, and worms. Vertebrate animals have a backbone and include fish, birds, reptiles and mammals.

Let's explore more about each below:

Fish

Animals come in a variety of shapes and sizes. Humans are animals. Did you know that cockroaches, jellyfish, and tapeworms are also animals? The Animal Kingdom is most likely the most diverse group of organisms. It contains elephants that can grow up to 13 feet tall and weigh up to 14,000 pounds; thus making them the largest land animals on Earth. However, the blue whale is the largest animal weighing over 100 tons. One of the smallest animals in the Animal Kingdom is the Brazilian Gold frog. The length of its body is about 10-12 mm. It could probably sit on the top of your fingernail. Both animals have another characteristic in common; they are both vertebrates. Vertebrates are animals that have a backbone or spinal column. Muscles can attach to an animal's backbone. The vertebral column provides structure, support, and protection for internal organs. Invertebrates do not have a spine and backbone. Vertebrates belong to the phylum Chordata. They can be further divided into seven classes: Mammalia, Reptilia, Aves, Amphibia, Agnatha, Chondrichthyes, and Osteichthyes.

Agnatha, Chondrichthyes, and Osteichthyes are different types of fish. They are the largest group of vertebrates. Fish are cold - blooded animals. They are unable to regulate their body temperature. Fishes lay their eggs in water. Agnatha are jawless fish. They are not only most likely the earliest type of vertebrate but also the most primitive fish. Chondrichthyes are fish with cartilaginous skeletons such as sharks. Osteichthyes are fish with bony skeletons. Tuna, trout, and seahorses are examples of bony fish. The two types of bony fish are ray- finned and lobe-finned fish. Unlike cartilaginous fish, bony fish have a swim bladder. It is an internal organ that fills up with oxygen to help the fish to remain buoyant. The swim bladder allows bony fish to save energy when it is not swimming. Fishes have gills to breathe. Gills are structures that take in dissolved oxygen and release carbon dioxide from water. All fishes live in water.

Swim bladder Cross Section, description below

See description of diagram

Amphibians

Amphibians can live on land and in water. They were most likely the first tetrapods to live on land. There are three groups of amphibians: frogs and toads, newts and salamanders, and caecilians. Most amphibians spend the early part of their lives in water. In order for their eggs to survive, many amphibians lay their eggs directly in water or on moist ground. Although adult amphibians live mostly on land, they must also keep their skin wet. Adult amphibians, such as frogs, have developed lungs and limbs. These adaptations have enabled them to live successfully on land. Their muscular hind legs and web feet are great for jumping to catch prey or escape predators. Salamanders have four limbs but they lack lungs. Salamanders obtain oxygen through the lining of their skin and mouth. The third group of amphibians is called caecilians. They are legless and resemble eels. The largest and most diverse group of amphibians consists of frogs and toads. Amphibians are cold-blooded animals.

Lizard Image Cold-blooded reptiles can become sluggish in cold weather. Lizards are often seen basking in the sun to get warm. Reptiles depend on energy from the sun to increase their body temperature. Lizards are found in warm climates such as deserts, rain forests, tropical islands, and swamps. Reptiles such as lizards live in many locations except for extremely cold regions. Reptiles have dry, scaly, and watertight skin. It helps retain body heat and minimize water loss without drying out. Except for snakes, reptiles have toes with claws which are very useful for climbing and digging. The claws also help them obtain a good grip on the ground which enables them to run very quickly over short distances. Unlike amphibians, reptiles have well developed lungs to help meet their need for oxygen.

The four major orders of reptiles are:

Testudines -turtles and tortoises
Squamata - snakes and lizards
Crocodilia - crocodiles and alligators
Sphenodontia - tuataras

Reptiles, birds, and a few egg laying mammals share one important characteristic which is the amniotic egg. Food and water is stored within the amniotic egg for the embryo.

Complete drag and drop activity below:

Birds

Birds Image Birds are closely related to reptiles. Birds may have developed from a prehistoric reptile. They share the following characteristics:

Scaly skin on their feet and legs
Oviparous (lay eggs)
They have claws
A cloaca that serves as the only opening for the reproductive, urinary, and digestive tract
Bone structure in their jaws

Birds belong to the class Aves. Their feathers are a unique characteristic that sets them apart from any other living thing in the Animal Kingdom. Feathers provide two major functions: lift for flight and conserving body heat. Birds are very lightweight because their bones are thin and hollow. However, their skeleton is very sturdy and strong. A third of their body mass comes from the muscles attached to their breastbone. These chest muscles extend from the breastbone to their wings. They provide the power for flight or swimming underwater. Just like mammals, birds are warm-blooded animals.

Warm-blooded animals can maintain their internal body temperature regardless of the temperature of their surroundings. Mammals are endothermic animals. They are able to regulate their body temperature by generating their own heat. Mammals can adapt to their environment. This advantage sets mammals apart from other animals. It also allows them to live in various locations around the world. Mammals have hair and fur. Layers of hair or fur help a mammal stay warm. Female mammals have mammary glands that produce milk to feed their young. Mammals share two more characteristics. They have a middle ear containing three bones to help them hear a wider range of sounds. They also have a jaw that enables them to chew food compared to animals that can only swallow or bite. There are three main groups of mammals.

Monotremes - have characteristics similar to reptiles such as laying amniotic eggs and the cloaca. The duck-billed platypus is an example of a monotreme.
Marsupials - their young develop inside a pouch attached their mother after they are born. Kangaroos, koalas, and opossums are examples of marsupials.
Eutherian - their young or babies are completely developed at birth. The baby receives nutrients, oxygen, and eliminates waste through an organ within the mother called the placenta. Humans, whales, and cattle are examples of eutherians.

As you have read, animals are a very diverse group of living things. So far you have learned about the different types of vertebrates in the Animal Kingdom. As you have read, they are a very diverse group of animals. However they make up a small percent of the Animal Kingdom. Invertebrates make up about 97% of all species of animals. Arthropods are the largest and most diverse group of invertebrates. This phylum makes up more than three- fourths of all known species of animals. Insects are the largest group of Arthropods. A few examples of insects are ants, bees, cockroaches, mosquitoes, and flies. The slides below will help you learn more about some common types of invertebrates.

Review the following presentations:

Animal Classification Review

Mammals
Reptiles
Birds
Amphibians
Insects

Characteristics of Mammals

Vertebrate
Hair or fur
They give birth to young
Ability to nurse
They require air to breathe and have lungs
If land dwelling, they have four legs and ears that stick out
Warm-Blooded

Characteristics of Reptiles

Vertebrate
Scales
Skin that is dry
Ear holes
Four legs or no legs
Most lay eggs, although some give birth to live young
Cold-blooded

Characteristics of Birds

Vertebrate
Feathers of wings
Lay eggs
Two legs
Ear holes
Warm-blooded

Characteristics of Amphibians

Vertebrate
Moist, smooth skin they do not have hair or fur
Land dwelling and water dwelling
Webbed feet
Breathe with lungs and gills
Four legs or none
Lay eggs
Cold-Blooded

Characteristics of Insects

Invertebrate - having a covered exoskeleton
Three part body: head, thorax, and abdomen
Six jointed legs
Dwell on land and in water
Most often have antenna for multiple purposes to hear, tough, taste and smell
Most often have four wings
Most often lay eggs but sometimes give birth to live young
Cold-blooded

[CC BY 4.0] UNLESS OTHERWISE NOTED | IMAGES: LICENSED AND USED ACCORDING TO TERMS OF SUBSCRIPTION