Biology Unit 11
Terms
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- General characteristics of all animals
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multicellular heterotroph
diversity
no cell walls
ability to move, greater mobility
sexual reproduction
embryonic development - zygote to
- morulla (solid ball of cells) to
- blastula (hollow ball of cells) to
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blastula with blastopore (folds inward, opening called a blastopore)
called gastrulation - parazoa
- no symmetry, tissues of organs
- eumetazoa
- animals with symmetry, tissue, organs, organ systems
- Classification by number of embryonic tissue layers
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- diploblastic
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two tissue layers, endoderm (inner) and ectoderm (outer)
found in Radiata - triploblastic
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three layers, ectoderm, mesoderm (middle) and endoderm
found in platyhelminthes through chordates - classification by looking at transitions in body plan
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- symmetry
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- asymmetry
- primitive, no symmetry shape but an irregular mass of cells, sponges
- radial symmetry
- parts of the body are arranged around a central axis, first seen in salt marine animals
- bilateral symmetry
- "sidedness"
- cephalization
- longitudinal nerve cords and clusters of cells in anterior regions of organisms probably led to the development of specialized organs like the brain
- body cavity
- a body cavity needs to exist to house specail organs
- acoelomate
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no body cavity
prorifera, radiata, platyhelminthes - psuedocoelomate
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a flase cavity of psuedocoel is a cavity between mesoderm and endoderm
nematoda, rotifera - coelomate
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a coelem (body cavity) develops with mesoderm
mollusks through chordates - coelomate characteristics
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since cavity is internal and fluids are prevented from circulating, circulating systems arose to carry materials to all cells
allows contact between mesoderm and endoderm cells which influence each other during development- called induction - classification by transition from non-segmented to segmented
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- advantages of segmentation
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1. a complete organ system in each system helps organism stay alive if one section gets damaged
2. better locomotion due to increased flexibility of motion - classification by type of digestive system
- for organisms with digestive systems with 2 openings (mouth and anus)
- protostomes
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mouth appears first developmentally
blastopore becomes the mouth
nematode through arthropoda - dueterostomes
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anus appears first developmentally
blastopore becomes anus
enchinodermata, chordata (links pro=fist, stomes=opening, deutero=second) - characteristics of chordates
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hollow dorsal nerve cord
notocord-flexible rod that is replaced by vertebra in higher organisms
pharyngeal slits (gill slits)
postanal tail - urochordata
- sea squirts and tunicates
- cephalochordata
- lancelets which look almost like fish
- vertebrata
- chordates with spinal columns
- characteristics of only vertebrates (not other 2 subphyla)
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vertebral column-bone replaces notochord
a well-differentiated head with a skull and a brain
neural crest during development
internal organs
endoskeleton - vertebrate reproductive styles
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- oviparity (oviparous)
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fertilization is internal, eggs laid outside the body
birds, some fish, reptiles, prmitive mammals - ovoviviparity (ovoviviparous)
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eggs form and are incubated and hatch inside the mother's body
some fish and reptiles - viviparity (viviparous)
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young develop inside the mother's body and obtain nourishment from mother's blood (not yolk)
in mammals (except monotremes) this occurs through placenta - vertebrate heart types
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- 2 chambered heart
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no separation of oxygenated and deoxygenated blood
fish - 3 chambered heart
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incomplete septum and some mixing of oxygenated and deoxygenated blood
amphibians, reptiles - 4 chambered heart
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complete septum. complete separation of oxygenated and deoxygenated blood
mammals, bird - major trends in vertebrate evolution
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ectothermal (cold-blooded) to endothermal (warm-blooded)
-high body size (more body mass or volume in relation to surface area, gives low heat loss)
3. diversification of teeth
4. better mobility-elongation, specialization of limbs
5. cartilage to bone
6. external fertilization to internal fertilization
7. oviparous to viviparous
8. 2 to 4 chambered heart
9. gills to lungs
10. cephalization