Lec 1: Animal Kingdom Flashcards
What Makes an Animal?
Chemoheterotrophs, multicellular, has collagen, sexual reproduction (2n dom)
when did animals evolve?
750mya
Animals colonization of land
450mya
Choanoflagellates
closest protist to animals (similar to choanocytes in sponges)
Conserved trait
Animal characteristic that has remained largely unchanged over long period
Non conserved trait
Animal characteristic that varies significantly between species due to different evolutionary adaptations
Germ layers
ectoderm: skin, parts of nervous system
mesoderm: skeletal muscles, bones/cartilage
endoderm: internal organs
Diploblastic
Animals that dev two germ layers (endoderm/ectoderm) ex: jellyfish
Triploblastic
Animals that develop 3 germ layers (endo/ecto/meso) ex: human
Pseudocoelomates
False body cavity ( body cavity bordered by mesoderm and endoderm) ex: roundworm, rotifers, nematodes
Coelomates
true body cavity (body cavity surrounded completely by mesoderm) ex: annelids, anthropods
Acoelomate
No true body cavity between digestive tract and outer body wall, instead filled with mesodermal tissue (ex: flatworms)
Phylum porifera
Sponges! simplest multicellular animal, radial symmetry, feeding cells = choanocytes, similar to choanoflagellates. Large central cavity = Spongocoel, Hole at top = osculum, spicules= hard support structures (glass/CaCO2) NO GASTRULATION no true tissue/organs, body forms = Asconoid, syconoid, leuconoid
class calcarea
Classified by calcium carbonate spicules, radial symmetry
class Hexactinellida
Classified by glass sponges, silica spicules, radial symmetry,
lack pinacocytes
class Demospongiae
Largest class (most diverse) skeleton made of silica spicules/spongin fibers
Phylum Cnidaria
Jellyfish, Corals, sea anemones, hydra. Radial symmetry, diploblastic, cnidocytes (stinging cells) nematocysts (organelles that release toxins to catch prey) Acoelomate
Phylum cnidaria life cycle
Medusa (adult sexual stage (n)) produces haploid gametes thru meiosis and egg/sperm combine to form 2n zygote which develops into planula larva (2n) which then settles on substrate to form polyp (2n) that reproduces asexually by budding (creating genetically identical polyps/medusas
class hydrazoa
polyp dom, portuguese man o war, contain cnidocytes, alt of gen, radial symmetry
class sycphozoa
classic jellyfish (medusa dom)
