TYPES OF ANIMALS

These are the common types of animals that live on the planet Earth:

Species in this group include humans, dogs, cats, bats, kangaroos, rhinos, hippos, apes, dolphins, whales. (From National Geographic.)

Endothermic	Warm-blooded	Body regulates a near-constant temperature, enabling them to live in multiple regions or conditions.
Viviparous	Give birth to live young.	Only two mammal species hatch from eggs: the duck-billed platypus and the echidna (spiny anteater).
Pelage	Presence of hair or fur, even in small quantities	protection, heating and cooling, sensation
Endoskeletal Vertebrates	They have bones that join to a centralized spine, including three bones in the middle ear.	They're bones are the centralized support system INSIDE the skin.
Exocrine Glands	sebaceous (fat secreting glands), sudoriferus (sweat), and scent glands.	Most significant for mammals are the mammary glands.
Complex mental network node	Brain is segmented into specific areas that control specific bodily functions, many autonomously (without thinking)	The neocortex region creates and controls seeing and hearing
Heterodont dentation	Specialized teeth	Incisors, Cuspids, Bicuspids, Molars
Four-chambered heart	Two atria and two ventricles	Keeps "clean" (oxygenated) and "dirty" (carbonated) blood separate, while also helping to regulate body temperature.

Species in this group include frogs, toads, salamanders, newts, and caecilians (blindworms). (From National Geographic.)

Mostly Endoskeletal Vertebrates	They have bones that join to a centralized spine.	The legless caecilians have scales INSIDE their skin, which makes them classified as having an exoskeleton.
Ectothermic, or cold-blooded	They cannot maintain their own body temperature and must have specific living conditions to survive.	Too much sun, wind, or man-made toxins can damage their skin and eventually kill them. As a result, amphibians are the first to disappear from an ecology, and why over 50% of all frog species are endagered.
Aquatic	They are usually born in water, and even when moving to land as an adult, they stay very close to their watery place of birth.	Some species require high levels of moisture to survive instead of a body of water. It depends on the species.
Complex Cutaneous Glands	1) some produce useful proteins, 2) some fight bacteria or fungus, 3) some are poisonous, as a defense mechanism	The most toxic amphibians are the most colorful.
Holometabolistic	Egg-Larva-Adult Life Cycle	Larvae are aquatic and free swimming, then reside mostly on land once their limbs and lungs have developed.
Carnivorous as adults	Some tadpoles and larval salamanders filter feed both plant and animal matter	Usually consume invertebrates like insects, arachnids, and earthworms, but there are a few that are large enough to eat small vertebrates.
External fertilization	Reproduce young outside the body in eggs
Cutaneous gas exchange	They breathe through their skin	With primitive lungs (some salamanders don't have lungs at all), oxygen, carbon dioxide, and other minerals are passed through the skin using water.

Species in this group include ostriches, penguins, terns, cranes, hawks, macaws, and hummingbirds. (From National Geographic.)

Endoskeletal Vertebrates	They have bones that join to a centralized spine.	Although their wings are mostly cartilage, their skeleton is under their skin and feathers.
Pneumatized bones	Bones are hollow for air intake	Allows for overall lighter weight (easier flight) and oxygen intake during flight
Endothermic	Warm-blooded, regulate their own body temperature	Can live in a variety of climates and environments
External fertilization	Young are produced outside the body in eggs, based on need for flight	Eggs are laid outside the body, in shells, instead of carried as extra weight.
Pregastric digestion	Birds usually eat while they fly, and then digest later.	Birds defecate regularly to keep their bodies light.
Murmuration	They have, or had at one time, adapted for flight (gliding and/or flapping)	It is believed that ostriches, emus, and penguins could fly at one time.
Adaptive Radiation	Quick evolution and adaption into multiple species	Most scientists believe birds came from the therapod dinosaurs. There are more than 10,000 different species of birds alive today
Migratory	Around 20% of species migrate long distances every year	Alpine swifts can fly up to 6 months nonstop; the Arctic Tern has the longest migration in the world, flying 56,000 miles roundtrip every year from the Netherlands to Antarctica

Species in this group include goldfish, catfish, gar, eels, sharks, swordfish, clown fish, and salmon. (From National Geographic.)

Ectothermic Vertebrates	With the exception of tuna and mackerel sharks, fish are cold-blooded, and cannot regulate their own body heat.	They have bones that join to a centralized spine.
Aquatic	Must have water to remain oxygenated, and have gills instead of lungs.	Most take in water through gills and separate the oxygen inside their bodies.	Some fish with stationary gills must stay moving in order to keep the flow of water coming in (sharks). Others - like lungfish - come to the surface and gulp air.
Increased Olefactory and Auditory Responses	Water transmits sounds, disperses chemicals, and conducts electricity better than air, so most fish don't rely too heavily on eyesight.	Most fish rely on hearing, taste, and smell, and some can navigate and detect food with either motion or electrical sensors.
Extreme Diversity	Since 70% of the planet is water, and each body of water is different, there are more than 32,000 different species of fish.	There are more fish than the number of amphibians, reptiles, birds, and mammals combined. Second only to insect class in number of species	The only animals with more numerous species than fish are insects.
Minimal Adaptations	Very old as an animal class.	According to fossil records, fish have existed for more than 500 million years.
External Fertilization	Reproduction happens outside the body	In most cases, females release eggs in the water to be fertilized by the males.	Baby fish are on their own from day one, and only the strongest and fastest survive to adulthood. It is theorized that fish instinctively travel in schools for protection, since they do not practice familial relationships.
Scales on top of skin	A scale is a rigid plate that grows from the skin of a fish both protects it from outside threats, and helps keep a proper balance of water inside and pressure outside the body.	There are cycloid scales (salmon), ctenoid scales (perch), ganoid scales (sturgeon), and placoid scales (sharks).	Eating fish scales is not dangerous, but it's not pleasant tasting.
Fins for limbs	Instead of 2 arms and 2 legs, and maybe a tail, fish often have 7 or more fins.	The increased viscosity (thickness) of water allows for less gravity, and a greater range of motion.	Water is closer to the conditions of the vacuum of space, which is why humans practice for space travel in water.
Swim Bladders	Internal gas-filled organ that allows a fish to control buoyancy	Filling and emptying the swim bladder, allowing the fish to move up and down, can keep a fish in motion for gill function without expending energy in the fins.	The swim bladder is reportedly the inspiration for Greek scientist Archimedes' development of his theories of fluid dynamics.
BONUS FACT	"Fish" is plural for "fish" when you have many of one type. "Fishes" is plural for "fish" when you have multiple species.	When you have more than one salmon - you have many FISH.	When you have salmon AND tuna AND sharks AND goldfish, you have many FISHES.

Species in this group include praying mantis, locusts, dragonflies, butterflies, bees, and ladybugs. (From National Geographic.)

All insects are arthropods, with arachnids, lobsters, and millipedes	Insects, however, have three pair of jointed legs, segmented bodies, antennae, and wings.	They also are NOT vertebrates. Arthropods have exoskeletons - a bony shell protecting their insides.
Scientists who study insects, or bugs, are called entomologists.	Entomologists believe that insects, the largest group of animals on the Earth, were also the first to leave the oceans for life on land.	The oldest insect fossil was found in Scotland, and is dated to be over 400 million years old.
Some form of insect lives in every single habitat on the planet, from the oceans to the poles.	So far, one million insect species have been identified, but four million are still uncategorized.	A small fly called the Chironomid Midge is the only insect that can be found in Antarctica, usually during the summer. FUN FACT: Iceland is the only country without mosquitoes.
Insects are vital to every ecosystem, and provide a variety of services.	They are pollinators, decomposers, and a food source.	Birds alone eat eat between 400 to 500 million tons of insects per year.
Most insects reproduce oviparously, which means by the laying of eggs outside the female body.	The eggs are normally laid near a food source, and the young pretty much have to survive on their own.	In a few aphids and beetles, the insects are all female, and simply clone themselves to reproduce. This is called parthenogenesis.