Body Symmetry Radial symmetry: extends from the
center outwards Ex:
Bilateral symmetry: sides are like mirror images (left and right) Ex:
Nervous System (Response)
Cephalization: concentration of sense organs and nerve cells in front (top) of the body
Evolution from ganglia (simple) to brain (complex)
Body Cavity
coelom: area of body cavity between the body wall and the digestive cavity
Acoelomate: animal that lacks a body cavity Ex: flatworm (planaria)
Pseudocoelomate: animal that has a partial body cavity Ex: roundworm (earthworm)
Embryo Development
Depends on what the blastopore develops into first…
Protostome: mouth develops first Ex: invertebrates
Deuterostome: anus develops first Ex: humans
Feeding and Digestion
Intracellular digestion: digestion occurs inside the cells Ex: sponges
Extracellular digestion: digestion occurs outside the cells in the digestive tract Ex: arthropods
Respiration (“Breathing”)
Gills: feathery structures that take in O2 from the water- usually close to the body surface Ex: fish
Alveoli: tiny air sacs at the end of the bronchiole that increase surface area and act in gas exchange Ex: humans
Vertebrate Introduction
Notochord: long supporting rod that runs below the nerve cord
Chordate: organism that has a dorsal nerve cord
Circulatory System
Open system: blood is not always in vessels Ex: insects, clams
Closed system: blood always in vessels Ex: humans
Movement and Support
Hydrostatic skeleton: move with water-filled cavity and accessory muscles
Ex: jellyfish
Exoskeleton: external skeleton on outside of body
Ex: insects
Endoskeleton: internal skeleton on inside of body
Ex: kangaroo
Reproduction External fertilization: eggs fertilized
outside the body (ex: coral)
Internal fertilization: eggs fertilized inside the body (ex: humans)
Oviparous: eggs develop outside the mother (ex: snake)
Ovoviparous: embryo gets nutrients from the yolk of egg (ex: seahorses)
Viviparous: embryo gets nutrients from mom (ex: humans)
Regulating Body Temp.
Ectotherm: body temp determined by environment- organism must Ex: lizards
Endotherm: body temp controlled internally Ex: dogs
Reproductive Strategies
K selection: having only a few offspring but investing a lot of parental care into them Ex: humans, gorillas
Occurs in crowded, competitive populations
r selection: having many offspring but investing very little parental care Ex: carp fish
Occurs in populations that grow and change rapidly