DLA-PABT: Phyla [Echinodermata, Chordata] Lesson

I've Always Wanted Wings!

Were you surprised that birds and humans belong to the same phylum? What are some characteristics that we share? Continue reading to find out.

Echinodermata and Chordata Notes

Read through the following facts about Phylum Echinodermata:

The Phylum Echinodermata is made up of the most advanced invertebrates and includes organisms such as the starfish, sea urchins and sea cucumbers. Echinoderm habitat is exclusively marine. The word echinoderm means spiny skin (echino = spiny, derm = skin) which is fitting; their endoskeleton is composed of calcium-based plates called ossicles that are covered by a thin skin.

FACTS:

• Echinoderms display 5-part radial (or pentaradial) symmetry as adults. They can be herbivores or predators. If sea stars or sea urchins lose a body part to a predator, they are able to regenerate those parts.
• A unique feature of all echinoderms is their water vascular system; these interconnected tubes allow them to move, feed and exchange gases (respiration).

Echinoderms, like chordates, are deuterostomes in which the blastopore (first opening in embryo) becomes the anus. All other invertebrates are protostomes, in which the blastopore in their development becomes the mouth.
Echinodermata Video

All Echinoderms Have:

1. No cephalization or brain, but they do have a nerve ring to coordinate movements in muscles between ossicles.
2. The water vascular system is made up of a system of canals; they help the organism feed and move. Water enters through an opening called the madreporite into a short stone canal into the ring canal. Radial canals connect to the ring canal and determine the five-part symmetry. This hydraulic water system is strong enough to help starfish open clamshells.
3. They can reproduce asexually by fragmentation or sexually with external fertilization.

Phylum Chordata

Which of the following pictures belong to the phylum Chordata?

If you said all of them, you are correct! Were you surprised? Continue reading to learn more about chordates.

Phylum Chordata Notes

Chordata Video

Two Vertebrate Adaptations: Endothermy and Amniotic Egg

Up to this point, all of the animals we have discussed have been ectotherms. An ectotherm is an organism that cannot regulate its own body temperature and must rely upon external sources of temperature for its metabolic rate. Lizards, for instance, are ectotherms and must bask in the sun or at a heat source to increase their internal temperature and activity. Sometimes these organisms are called "cold-blooded."

We will see that some of the Vertebrates have developed the adaptation of endothermy. An endotherm is an organism that has the ability to regulate its body temperature independent of the environment. Endotherms, such as mammals, are able to increase and regulate their temperature internally by metabolic processes. Sometimes these organisms are called "warm-blooded."

Why are Vertebrates Important?

Within the Craniata are the Vertebrates, which include fish, amphibians, reptiles, birds, and animals. Vertebrates have a number of features that make them successful:

1. Endoskeleton with a backbone (spinal cord protected by vertebrae)
2. Cephalization with a skull for protection
3. Jaws
4. Complex brains
5. Sense organs
6. Organ systems present
7. Coelom
8. Closed circulatory system, chambered heart
9. Endo- or Ectothermic
10. Bilateral symmetry
11. Two pairs of jointed appendages (limbs, fins)

Vertebrates can be further subdivided into the fish and the tetrapods, which have four limbs:

Fish:

• Class Agnatha (jawless fish)
• Class Chondrichthyes (cartilaginous fish)
• Class Osteichthyes (bony fish)

Learn more about each of these classes from the presentations below:

Tetrapods:

• Class Amphibia (amphibians)Class Reptilia (reptiles)
• Class Aves (birds)
• Class Mammalia (mammals)

Learn more about each of these classes from the presentations below:

Challenge and Before You Go

Practice Time! Use the knowledge you learned from the lesson to complete the practice activities below.

 Before You Go - You Need To Know

The following key points are from the explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

1. What makes Phylum Echinodermata unique?
   • Spiny skin
2. What makes Phylum Chordata unique?
   • A notochord during development
3. What are two adaptations that make Phylum Chordata unique?
   • Amniotic egg and endothermy

IMAGES CREATED BY GAVS (FREEPIK)