Kingdom Animalia and Development

  1. characteristics of animals
    • eukaryotic and multicellular
    • heterotrophic (internal digestion)
    • motile (in most life stages)
    • diploid
    • lack cell walls; have extracellular matrix instead
    • embryonic layers that become tissues
  2. reproduction
    • gametic life cycle
    • dominant phase is diploid
    • asexual is common (unfertilized eggs, some inverts)
  3. cleavage
    • the diploid zygote begins division
    • cells divide but do not increase in size
    • followed by blastula formation
  4. blastula formation
    a clump of cells form a hollow ball (blasatula) filled with fluid
  5. gastrulation
    invagination of the hollow ball through cell migration creates two layers of cells (endoderm and ectoderm)
  6. archenteron
    • interior cavity of the gastrula
    • eventually forms the digestive tract
    • hole on one side is blastopore; becomes mouth/anus depending on species
  7. different ways that zygote develops into adult:
    direct process or metamorphosis
  8. adult
    sexually mature organism
  9. direct process
    • gradual development
    • child looks like a mini-adult
  10. metamorphosis
    • juveniles (larvae) look different from adult; behaviors may differ
    • undergoes a dramatic change into adult stage
  11. Hox genes
    • produce proteins that control the action of other developmental genes
    • contain 180 nucleotide sequences (homeoboxes)
    • probably evolved early
    • in all animals, variations in some plants
    • deals with pattern formation, appendage positioning, differentiation
    • diversity in homeoboxes can explain diversity in body form
  12. hypotheses for diversification of animal phyla (cambrian explosion):
    • prevalence of oxygen and availability for aerobic respiration allowed for bigger, more complex forms
    • formation of Hox genes and variations
    • new predatory/prey relationships required evolutionary advantages over the other
  13. bilateral symmetry
    • typically motile
    • different planes of division: dorsal/ventral, left/right, anterior/posterior
    • cephalization
    • adapted for those who move into their environment headfirst
  14. radial symmetry
    • typically sessile or planktonic
    • allows organisms to meet environment from all sides
    • dorsal/ventral plane
  15. germ layers
    • in embryo
    • give rise to animal tissues
    • ectoderm, endoderm, mesoderm
  16. diploblastic
    • includes endoderm and ectoderm
    • ex cnidarians
  17. triploblastic
    • includes ectoderm, endoderm, and a mesoderm
    • typical of bilaterally symmetric organisms
  18. ectoderm
    gives rise to skin (integument), nervous system
  19. endoderm
    gives rise to digestive organs
  20. mesoderm
    • between ectoderm and endoderm
    • gives rise to other organs
  21. coelomate
    • have a body cavity (coelom)
    • organs are suspended
    • allows for independent movement of organs
    • ex human, earthworm
  22. acoelomate
    • no body cavity
    • tissues directly oppose one another
    • ex flatworm (platyhelminthes)
  23. pseudocoelomate
    • cavity only partially lined by mesoderm
    • ex roundworm
  24. spiral cleavage
    the planes of cell division are diagonal to the vertical axis of the embryo
  25. determinate cleavage
    rigidly casts the developmental fate of each embryonic cell very early
  26. radial cleavage
    cell division planes are either parallel or perpendicular to the vertical axis of the embryo
  27. indeterminate cleavage
    each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo
  28. deuterostomes
    • radial, indeterminate cleavage
    • the coelom forms from mesodermal outpocketings of the archenteron
    • blastopore develops into anus
  29. protostomes
    • spiral, determinate cleavage
    • the coelom forms from splits in the mesoderm
    • blastopore develops into mouth
  30. metazoa
    the animal clade
  31. eumetazoa
    animal clade with true tissues
  32. clade bilateria
    • bilateral symmetry
    • triploblastic
  33. clade deuterostomia
    • chordates, other phyla
    • traditional and molecular views of animal phylogeny disagree as to which other phyla are also deuterostomes
  34. three major clades of bilaterally symmetrical animals
    • deuterostomia
    • lophotrochozoa
    • ecdysozoa
  35. ecdyzoa
    • nematoda, arthropoda
    • exhibit ecdysis
    • secrete external skeletons
  36. lophotrochozoa
    • platyhelminthes, rotifera, ectoprocta, brachiopoda, mollusca, annelida
    • lophophore and trochophore larvae
  37. deuterostomia
    echinodermata, chordata
Card Set
Kingdom Animalia and Development
body plans, derived features