Amphibians: Live in the water as larvae and on land as adults. Reproduce in water and have lungs (frogs, toads, salamanders).
Birds: Have feathers, lightweight bones, scale-covered legs, and front limb wings (ostrich, cardinal, eagle, hawk).
Reptiles: Have dry, scaly skin, strong limbs, lay eggs, and are cold-blooded (lizard, snake, tortoise).
Mammals: Have mammary glands used to feed young, hair, and a four-chambered heart (human, dog, cat).
Bony Fish: Fish with a strong, bony skeleton (tuna, bass, trout, other fish).
Cartilaginous Fish: Fish with a cartilage skeleton, providing greater body movement control (sharks, rays, skates).
Jawless Fish: Lampreys and hagfish.
Human Classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: Sapien
Primates: Intelligent and social creatures exhibiting complex behaviors; mammals with relatively long fingers and toes with nails instead of claws, strong clavicles, binocular vision, and a well-developed cerebrum (humans, apes, monkeys).
Hominin: Primates that have opposable thumbs and large brains (chimpanzees, gorillas, humans).
Homo: Group of hominins that resemble modern humans from ancient times till now; distinctions due to adaptations over time.
Human Levels of Organization
cells → tissues → organs → organ systems → organism
Specialized cells organized into tissues.
Epithelial Tissue: Creates protective boundaries and is involved in the diffusion of ions and molecules (skin, intestines, other organs).
Nervous Tissue: Transmits and integrates information through the central and peripheral nervous systems (brain, spinal cord, nerves).
Muscular Tissue: Contracts to initiate movement in the body (skeletal, cardiac, smooth).
Connective Tissue: Underlies and supports other tissue types (tendons, cartilage).
Human Systems: Digestive
Function: Converts food into small molecules that can be used by the cells of the body.
Related Organs: Mouth, Esophagus, Stomach, Pancreas, Liver, Gallbladder, Small intestine, Large intestine, Anus
Human Systems: Excretory
Function: The system responsible for eliminating metabolic waste.
Related Organs: Skin (removes water, salts, small amounts of urea), Lungs, Liver, Kidneys, Bladder, Urethra
Human Systems: Circulatory
Function: Transports oxygen, nutrients, and other substances throughout the body and removes wastes from tissues.
Related Organs: Heart, Blood vessels (arteries, capillaries, veins), Blood
Human Systems: Lymphatic
Function: A network of vessels, nodes, and organs that collects the lymph (blood cells and plasma) that escapes the capillaries and returns it to the circulatory system.
Related Organs: Thymus, Tonsils, Bone marrow, mucous membranes, lymph nodes, Spleen
Human Systems: Respiratory
Function: Picks up oxygen from the air as we inhale and releases carbon dioxide as we exhale.
Function: Serves as a barrier against infection and injury, regulates body temperature, removes wastes, gathers sensory information, produces vitamin D.
Related Organs: Skin, Hair, Nails, Glands
Human Systems: Endocrine
Function: Release hormones that travel through the blood and control the actions of cells, tissues, and organs.