Give You Health: Octopus

Give You Health: Octopus

Reptiles: Lizards, Snakes, and Others

Reptiles have been around for 300 million years, even during the dinosaur age. The most common reptiles include alligators, crocodiles, lizards, snakes, tortoises and turtles. Reptiles are air-breathing animals, although many live not only on land but in water. The most noticeable feature of reptiles are the scales that cover their body. The majority of reptiles lay eggs to give birth to their young.

Although reptiles breathe through lungs, some reptiles can also absorb oxygen in water through membranes in their mouth.

Reptiles are often called cold-blooded because they can't regulate their own body temperature. Their body temperature depends on the external temperature. They will lay in the sun to heat their body, or hide in the ground, under a rock or in water to cool their body.
crocodile

Frogs

 Amphibians lay their eggs in water, and young amphibians tend to resemble small fish. The tadpole, or newborn frog, is born and lives in water. It has a tail that allows it to swim like a fish. It also has gills so that it can breathe under water. As the tadpole grow into a frog, it loses its gills and tail, and develops legs for moving on land. Most amphibians can both walk and swim in water.

Depending on the species of amphibian, breathing can take place in gills, lungs, the lining of the mouth, the skin, or some combination of these. Amphibians body temperature changes with its environment. In cold climates, amphibians hibernate during the winter.

Vertebrata

This water is home to over 20,000 different species of fish. The earliest fossils of fish date back over 400 million years.

There are a wide variety of fish — from the goby which is less than one half an inch long, to the whale shark which can be over 60 feet long.

Most fish breathe through gills. Gills perform the gas exchange between the water and the fish's blood. They allow the fish to breathe oxygen in the water.
Fish

Fishes are vertebrates that have a skeleton made of either bone or cartilage. About 95% of fishes have skeletons made of bone. These bony fishes have a swim bladder, a gas-filled sac, that they can inflate or deflate allowing them to float in the water even when not swimming.

Annelids

Earthworms

There are about 9,000 species of Annelids known today, including worms and leeches. They can be found almost anywhere in the world. Annelids have existed on Earth for over 120 million years.

Annelids have bodies that are divided into segments. They have very well-developed internal organs. One common characteristic of annelids is that they don't have any limbs.

Some annelids may have long bristles. Others have shorter bristles and seem smooth, like the earthworm shown here.

There are many types of worms. Commonly known worms include earthworms, roundworms and flatworms. Most worms are small, measuring fractions of an inch to several inches long. Other worms, such as the ribbon worm, can grow up to 100 feet in length. Some worms are considered parasites, in that they live inside the human body.

Echinoderms

Echinoderms are marine animals that live in the ocean. Common echinoderms include the sea star, sea urchin, sand dollar and sea cucumber. Most echinoderms have arms or spines that radiate from the center of their body. The central body contains their organs, and their mouth for feeding.

Sea stars, commonly known as the starfish, have 5 or more arms attached to their body.

On the bottom of the Starfish are small tube feet to help with movement and feeding. The starfish's mouth is underneath, and is capable of eating other sea life such as clams and mussels.


Another type of echinoderm is the sea urchin. Sea urchins have many spines connected to their body. These spines help to protect them from predators.

Want to learn more about echinoderms? See our echinoderm video collection.

Invertebrates

PROTOZOA

Protozoa are simple, single-celled animals. They are the smallest of all animals. Most protozoa are microscopic in size, and can only be seen under a microscope. However, they do breathe, move and reproduce like multicelled animals.

There are several types of protozoa. The amoebas are clear, shapeless cells. Flagellates have a body shape looking like a hair.

Although we can't see them, protozoa do a lot for us. Protozoa play a useful role in the food chain as a source of food for fish and other animals. Some protozoa are helpful to humans by eating dangerous bacteria. Unfortunately, other protozoa are parasites and can be harmful to humans by transmitting disease.


Protozoa eat tiny algae and bacteria. Some protozoa absorb food through their cell membrane. Others surround and engulf their food or have openings to collect food. They digest their food in stomach-like compartments called vacuoles.

Protozoa take in oxygen and give off carbon dioxide through the cell membrane.

Protozoa reproduces by splitting in half.