Animals

Animal Characteristics

Multicellular
Heterotrophs
Release energy from food
Cells need oxygen
Reproduce (Most reproduce sexually, some reproduce asexually)

Classification

Classified by:
- How it looks
- How it develops
- Content of DNA

Vertebrates - Animals with backbones
Invertebrates - Animals without backbones

Animal Symmetry

Bilateral Symmetry - One line that divides an animal into two equal halves. (mirror images)
Radial Symmetry - Animals with many lines of symmetry that all go through a central point.
No Symmetry - Animals that cannot be divided into equal halves by a line of symmetry.

Bilateral Symmetry

Radial Symmetry

No Symmetry

Sponges

Live in water all over world
Invertebrates
Generally no body symmetry
No tissue or organs
Has many tiny pores
Reproduces – Asexually (budding) and Sexual (fertilization)

Cnidarians

Invertebrates
Stinging cells to capture food and defend
Radial symmetry
Tentacles that contain stinging cells
Reproduces – Asexual and Sexual
Two types: Medusa and Polyp

Medusa - Bowl-shaped body plan, Swimming life, Mouths open downward, Tentacles trail down
Polyp - Vase-shaped body plan, Mouth opens at top, Tentacles spread out from mouth, Attaches to underwater surface

Worms

Invertebrates
No legs
Bilateral symmetry
Reproduce – asexually and sexually
Three types: flatworms, roundworms, segmented worms.

Mollusks

Invertebrates
Unsegmented bodies
Bilateral symmetry
Have an organ called a foot
Three types: gastropods, bivalves, cephalopods

Arthropods

Invertebrates
Exoskeleton – external skeleton
Molting: when an animal sheds the exoskeleton
Segmented body
Bilateral symmetry
Appendages (used to move)
Reproduces sexually
Four Groups: insects, crustaceans, centipedes, and millipedes

Insects (Arthropods)

Largest group of arthropods
Three body sections (head, thorax, abdomen)
Three pairs of legs (six legs)
One pair of antennae
One or two pairs of wings
Complete Metamorphosis (egg, larva, pupa, adult)
Gradual Metamorphosis (egg, nymph, mini adult, adult)

Crustaceans (Arthropods)

Watery environments
Two or three body sections
Five or more pairs of legs
Two pairs of antennae
Gills to obtain oxygen
Scavengers or predators

Arachnids (Arthropods)

Two body sections
Four pairs of legs
No antennae
Four types: spiders, ticks, mites, scorpions
Spiders - Predators, Hollow fangs, Spin webs
Ticks - Parasites, Sucks blood
Mites - Parasites, Live all over the world
Scorpions - Live in hot climates, Active at night, Spine-like stinger

Centipedes & Millipedes (Arthropods)

Two body sections
Numerous pairs of legs
One pair of antennae
Centipedes (One pair of legs per segment, Predator, inject venom)
Millipede (Two pairs of legs per segment, More than 80 segments, Scavengers)

Echinoderms (Arthropods)

Invertebrates
Endoskeleton – internal skeleton
Radial symmetry
Water vascular system
Reproduction – egg, larvae, metamorphosis
Major groups: sea stars, brittle stars, sea urchins, sea cucumbers

Fish

Largest group of vertebrates
Live in water
Have fins to help swim
Ectotherms – Body temperature changes depending on the environment.
Obtain oxygen through gills
Have scales
Reproduce – external fertilization
Three groups: Jawless, Cartilaginous, Boney

Amphibians

Salamanders, frogs, and toads
Begins life in water, spends adulthood on land
Reproduces – egg, embryo, larvae, metamorphosis.
Gills as youth to get oxygen, lungs as adult
Strong skeletons and limbs to move on land

Reptiles

Vertebrates
Ectothermic
Scaly skin
Lay eggs on land
Oxygen from lungs
Carnivores
Groups: lizards, snakes, alligators, crocodiles, turtles

Birds

Vertebrates
Endothermic - Regulates body temp by controlling the internal heat it produces
Lay eggs
Have feathers
Most fly (hollow bones)
Scales on feet and legs
Bills - used to capture, grip, and handle food

Mammals

Vertebrates
Endothermic
Skin covered with hair or fur
Most young born alive
Four-chamber heart, pair of lungs
Teeth – chew and tear food
Three groups: monotremes, marsupials, and placental mammals
Monotremes - Just three species, two species of anteaters and the duck-billed platypus. Lay eggs, hatch young, and finish developing outside the egg.
Marsupials - Koalas, kangaroos, opossums. Young born at young age, develop in mother’s pouch
Placental - Most mammals, including humans. Young develops inside mother’s body until able to function independently