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Comparing Evolutionary Trends in Invertebrates and Vertebrates. (Chapters 29 + 33). Body Symmetry. Radial symmetry: extends from the center outwards Ex: Bilateral symmetry : sides are like mirror images (left and right) Ex: . Nervous System (Response).
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Comparing Evolutionary Trends in Invertebrates and Vertebrates (Chapters 29 + 33)
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
Excretion • Roles: • control the output of waste products • Involved in water balance
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