chapters 25 and 26 Flashcards
Give the 6 traits that identify organisms as animals.
- multicellular 2. eukaryotic 3. heterotrophic 4. no cell walls 5. usually motile 6. usually ingests food
Give the 4 survival needs of animals
- maintain homeostasis 2. obtaining and circulating nutrients 3. collecting and excreting wastes 4. gathering and responding to information
animals with backbones
vertebrates
animals without backbones
invertebrates
the phylum of organisms that includes vertebrates, have two cords running down their back at some point in their lives
chordates
Give the four major traits of chordates.
- notochord 2. dorsal, hollow nerve cord 3. pharyngeal slits/pouches 4. post-anal tail
What does the notochord become in humans and other vertebrates?
structural support, backbone (spine) or vertebrae
What does the nerve cord become?
spinal cord and brain
What do the pharyngeal slits and pouches become in humans?
part of the ear and throat
What do the pharyngeal slits and pouches become in fish?
gills
a fertilized egg
zygote
the early cell divisions, divide into progressively smaller, identical cells called blastomeres
cleavage
the identical cells within a blastula, created by cleavage
blastomeres
the solid ball of cells created by cleavage
morula
the hollow ball of cells created by cleavage
blastula
the stage in embryonic development created by the invagination (bending in) of the blastula
gastrula
the opening into the gastrula
blastopore
What two possible things does the blastopore become?
mouth or anus
having no symmetry
asymmetry
having circular symmetry like spokes on a wheel where body parts extend outward from a center point
radial symmetry
having one plane of symmetry with two mirror halves
bilateral symmetry
Which type of symmetry is best in more active animals?
bilateral
Which type of symmetry is best in sessile animals or ones that don’t move much?
radial
5-part radial symmetry common in echinoderms
pentaradial
