Login
Copyright

Major Animal Phyla & Their Characteristics

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Exotic Animals: Definition & Names

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:03 What Is an Animal?
  • 0:36 Porifera & Cnidaria
  • 1:27 Platyhelminthes,…
  • 2:39 Arthropoda & Mollusca
  • 4:00 Echinodermata & Chordata
  • 6:30 Lesson Summary
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Login or Sign up

Timeline
Autoplay
Autoplay
Create an account to start this course today
Try it free for 5 days!
Create An Account

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Amanda Robb
In this lesson, we'll be learning about the nine major phyla of Kingdom Animalia. We'll go over what types of animals are in each phylum, as well as describing some characteristics of the phylum's members.

What Is an Animal?

When you think of an animal, you might think of your dog, or you might even know from biology class that you're an animal too. Animals aren't just organisms that walk on four legs. Bugs, jellyfish, and even sea sponges are all animals. In kingdom Animalia, there are nine phyla, or subdivisions, of animals. Phyla are organized from the least evolved, Porifera, to the most evolved, Chordata. As we progress through the phyla, discussing some example animals along the way, you'll notice more complex body systems emerging.

Porifera & Cnidaria

Phylum Porifera is made up of sea sponges, which are stationary plant-like organisms we find in colorful coral reefs. But sea sponges are actually basic filter feeding animals, meaning they strain water in through their walls to capture food. They also have no definite shape, nor do they have a body cavity, like the space our organs are contained in. They're simply made of a few layers of cells organized into a column.

Phylum Cnidaria consists of jellyfish and hydras, which are squishy animals that have a more complex feeding system than Porifera. Most have some sort of tentacle with stinging cells, called cnidocytes, that can capture small prey. These organisms also have a basic nervous system called a nerve net but no brain or conscious thought. They can, however, sense their environment and respond to it.

Platyhelminthes, Nematoda, & Annelida

Phylum Platyhelminthes is made up of flatworms, which have a flattened body with an incomplete digestive tract like Poriferans and Cnidarians, meaning the mouth is the same opening as the anus. The most well-known member of Platyhelminthes is the planarian, a common model animal in biology known for its ability to regenerate its body, even after being cut into many pieces.

Phylum Nematoda includes the round worms, which have a complete digestive system, a new feature in animal evolution, meaning they have separate holes for the mouth and anus. Nematodes are mostly free living, but some parasitic nematodes are more well-known to humans. The species Trichinella spiralis causes the illness trichinosis, which is transmitted by eating infected pork.

Phylum Annelida includes our classic, segmented worms, like the ones birds eat from the ground. Annelids have a complete digestive system, and even have specialized organs within it, like the intestine, esophagus, crop, and gizzard. They also have a closed circulatory system where blood is enclosed in vessels like ours as well as basic excretory organs to remove waste.

Arthropoda & Mollusca

Phlyum Arthropoda is made up of all of the creepy crawly animals such as spiders, centipedes, bees, scorpions, and even insects like praying mantises and butterflies. Surprisingly, crustaceans like crabs and lobsters are also arthropods. If you look closely, you can see the similarities, including:

  • An exoskeleton, or outer shell
  • body segments, and
  • antennae

Arthropods have a complete digestive system but not a closed circulatory system. Their nutrients simply move around the body in a liquid called hemolymph.

Phylum Mollusca consists of the soft squids, sea snails, clams, cuttlefish, and octopi of the ocean, as well as snails and slugs on land. Most of the animals are protected by a hard shell as you can see on clams and snails. But some of the sea mollusks have other adaptations to survive. Octopi are one of the smartest invertebrates, or organisms without a backbone. They have a well-developed nervous system with a complex brain, and are able to learn puzzles and use new techniques to capture prey. These organisms are built for speed with a closed circulatory system and quickly run down prey, using their razor sharp beaks and poison to kill. Many octopi employ camouflage as well for extra stalking abilities.

Echinodermata & Chordata

Although you might not think of these animals as closely related to humans, surprise! Phylum Echinodermata includes sea squirts, sea urchins, and sea stars, and, although these animals might look a lot like plants, they're part of our closest related phylum. Although we are very different from these animals, their patterns of development are similar to other animals in the phylum Chordata, which is the one that includes humans.

Phylum Chordata is made up of the animals we know and love, including everything from fish and birds, to monkeys and lizards, to dogs and humans. Chordates have a dorsal hollow nerve tube and a notochord, which became our vertebrae and spinal cord. We also all have a muscular post-anal tail, or remnants of it, like in humans, and pharyngeal slits that will eventually become lungs in land animals. The most basic chordates are tunicates, which mostly live as immobile sea creatures. However, early on in their development, they have all the characteristics of a chordate, placing them in our phylum.

To unlock this lesson you must be a Study.com Member.
Create your account

Register for a free trial

Are you a student or a teacher?
I am a teacher

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back

Earning College Credit

Did you know… We have over 95 college courses that prepare you to earn credit by exam that is accepted by over 2,000 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it free for 5 days!
Create An Account
Support