animal diversity

• the main characteristics of animals are being eukaryotic, multicellular, lacking cell walls, heterotrophic, sexual reproduction, and complex development
• life cycle of animals is a diploid adult does meiosis, one gamete combined w other and fertilizes, makes a diploid zygote that mitosis to make a diploid adult
• animals have different types of body plans including bilateral symmetry (head-tail), radial symmetry (top-bottom), and irregular symmetry (no pattern)
• bilaterally symmetrical animals include protostomes (mouth first) and deuterostomes (anus first)
• protostome examples include mollusks, annelids, arthropods, nematodes, flatworms, and platyhelminthes
• animal phyla include protostomes (mouth develops first) and deuterostomes (anus develops first)
• protostome examples include mollusks, annelids, arthropods, nematodes, platyhelminthes, rotifers, flatworms, and spiralians
• deuterostome examples include chordates, echinoderms, hemichordates, and xenacoels
• what are body plans?

  Overall organization of an animal's body
• how many animal phyla are there?

  35
• what data do body plans combine?

  morphological, molecular, fossil
• body plans are sets of morphological and developmental traits, map onto phylogenies
• radial symmetry is when the body is symmetrical around the centre of the body, such as a flower
• bilateral symmetry is when the body is symmetrical on both sides of the body
• superior position is above
• posterior position is behind
• inferior is below
• anterior is ahead or front facing
• rostral is here the nose or face is
• caudal is where the tail or tailbone is
• dorsal is where the back is
• ventral is where the stomach/belly is
• body plans can be traced back to embryonic development
• cleavage is the rapid cell division in zygotes following fertilization
• a blastula is the embryonic stage consisting of a multicellular hollow ball of cells made FROM cleavage
• a blastocoel is the hollow space inside a blastula
• a gastrula is the embryonic stage consisting of different tissue layers, made from gastrulation
• what are the steps to gastrulation?


  • zygote does mitosis to divide rapidly into 8 cells stage
  • cleaves to make a blastula, cells move to make hollow inside
  • cells are pushed into the ball becomes a gastrula
• a gastrula is the 3rd stage of embryonic development, it is the first stage of organogenesis, cell pushes inward
• the ectoderm is the outer tissue layer of the embryo and is the site of neural, epidermal and sensory development
• the endoderm is the inner layer of the embryo and forms the gut and digestive tube
• the mesoderm is the middle layer of the embryo and gives rise to the muscles, bones, and connective tissue
• a diploblastic organism is one with two layers of cells and radial symmetry
• a triploblastic organism is one that has three germ layers and bilateral symmetry
• sponges lack true tissues or organs but do contain differentiated cell types
• a coelom is a membrane-bound organ that contains a fluid-filled space, body cavities, houses organs and is within mesoderm
• a coelomate is bilateral and triploblastic, mesoderm has a layer of coelom
• pseudocoelomates have a body cavity but no true coelom, mesoderm has a muscle layer, connects all the way around the mesoderm, space between mesoderm and endoderm derived tissue
• an acoelomate has no coelom, only ectoderm, endoderm and mesoderm
• a protostome is spiral (off center division) and determinate (knows where its supposed to be by 8 cell stage during cleavage, mesoderm is separated off before gastrulation