Chapter 22 Flashcards
what is an animal
- multicellular
- heterotrophic (eats other organisms)
- internal digestion (vs fungi)
- motility (muscles, nerves, skeletons)
are animals monophyletic or polyphyletic
monophyletic
who is presumed to resemble animal’s common ancestor
colonial choanoflagellates
earliest and simplest animals were:
marine
sponges
- lack tissues
- body form is cup shaped
- inner surface composed of choanocytes (flagella beat to draw water through pores to central cavity)
diploblastic animals
have 2 body layers, central gastrovascular cavity, noncentralized nerve net, aquatic (body supported by water)
- have ectoderm and endoderm
- ancestral condition
jellyfish and comb jellies
- 2 body layers in embryo
- distinct organ systems
- radial symmetry
radial symmetry
if you spun around animal, couldn’t tell where she started
-simpler animals
more complex animals have…
- 3 embryonic layers
- bilateral symmetry
bilateral symmetry
can tell where you started, obvious anterior/posterior ends
- associated with cephalization (concentration of sensory organs and nervous tissues at anterior end)
- more advanced animals
types of deuterostomes
chordates and echinoderms
types of protostomes
lophotrochozoans and ecydosoans
deuterostomes
blastopore becomes anus
-humans
protostomes
blastopore becomes mouth
major traits
-anterior brain that surrounds the entrance of the digestive track
-ventral nervous system containing paired or fused longitudinal nerve chords
acoelomates
do not have enclosed body cavity
pseudocoel
lined with mesoderm, but no mesoderm surrounds internal organs
2 major animal clades
protostomes deuterosomes
lophotrochozoans
- bryozoans, molluscs, annelids
- common larval form, feeding apparatus
- have a lophophore (feeding structure) and a trochophore (free living larval stage)
ecdysozoans
- arthropods, nematoads
- shed exoskeleton to grow
deuterostomes
- echinoderms, hemichordates, vertebrates
- mouth forms second
most species rich/successful animals
arthropods
arthropods
- most complex of ecdysozoans
- success due to body supported by an exoskeleton (chitin) segmented body plan (metameric) and paired jointed apendages
types of arthropods
crustaceans, hexapods, myriapods, chelicerates
crustaceans
marine, terrestrial
EX: lobster
hexapods
terrestrial
ex: grasshopper
myriapods
example: myriapods
chelicerates
have distinct mouth, body segmentation, 6 legs
ex: horseshoe crab, spiders
tardigrades
- limbs not jointed, but still arthropod
- when too dry, shrink up, can survive a decade
nematodes
-round worms
-no segmentation
-scavengers, predators, or parasites
EX: trichinella (swine parasite) caenorhabditis elegans (lab animal)
molluscs characteristics
- have a foot (locomotion)
- internal organs (visceral mass)
- mantle (secretes shell)
types of molluscs
- gastropods: snail
- bivalves: clams
- cephalopods: octopus
annelids
earthworms, leeches, segmented bodies
flatworms
flukes, tapeworms. most are internal parasites. simple bodies that often lack digestive track
rotifers
have a ciliated corona- for bringing food into mouth
-for some species, only females no males exist
bryozoans
colonial
echinoderms symmetry
evolved from bilateral ancestor, but exhibit radial symmetry as adult
echinoderms
- most are radially symmetric as adults
- larvae are bilaterally symmetric
- move and feed using tube feet
chordates
- dorsal, hollow nerve chord
- postanal tail for locomotion
- notochord
- pharangeal slit for gas exchange
types of chordates
lancets, tunicates, vertebrates
important innovation of chordates
gained jaws, ability to chew larger prey and grow larger
jawed fish
- cartilaginous fish (sharks, reys)
- bony fish (ray finned)
- lobe fins
most primative tetrapods
amphibians
types of amphibians
frogs, salamanders, caecelians (secondarily lost limbs)
amphibians
- moist skin (need to stay near water)
- require water for eggs (no shell)
- wet habitats
vertebrate innovations
- internal skeleton
- with vertebrae
- made of bone vs cartilage
- jointed limbs
- nares to breathe air
- terrestrial limbs
- amniotic eggs: withstand dry conditions
types of amniotes
reptiles, mammals
types of reptiles
turtles, tuataras, squamates (snakes and lizards), crocodilian, dinosaurs and birds
reptiles
- amniotic egg provides private pond
- scales (keratin vs bone-derived scales of fish)
mammals
- mammary glands
- sweat glands
- 4 chambered heart
- hair
- teeth are varied
types of mammals
prototherians, marsupials, eutherians
prototherians
lay eggs
marsupials
newborns move to pouch
eutherians
more developed at birth, 20 major groups
morphological synapomorphies of animals
extracellular matrix, cell junctions
triploblastic
ectoderm, endoderm, and mesoderm
monoblastic
no layers, aka sponges
5 key features of body plans
- the symmetry
- structure of the body cavity
- segmentation of the body
- existence and location of external apendages
- development of the nervous system
primates characteristics
grasping limbs, opposable thumbs, evolved through paleogene and neogene
strepsirrhines
wet nosed primates
haplorhines
dry nosed primates
