Animals Flashcards
animals
heterotrophic, eukaryotes, tissues from embryonic layers (muscle and nerve - think and move on our own)
reproduction
most sexually, diploid stage dominates
- zygote
- eight-cell stage
- blastula (hollow ball of cells)
- gastrulation (ball indents)
- gastrula
Gastrula and gastrulation
last stage of embryo before differentiation
- blastopore/protostome (indentation)
- archenteron (digestive tract)
- 3 germ layers: ectoderm, mesoderm, endoderm
cleavage
series of mitotic divisions without cell growth between the divisions, begins immediately after fertilization
larval stage
not yet adult, sexually immature, have to go through metamorphosis, different food sources and habitats
metamorphosis
developmental transformation from juvenile to adult (tadpole to frog- no legs or lungs and live in water), (caterpillar to butterfly- eats leaves then nectar)
ediacaran biota
550 million years ago, animals were extinct
cambrian explosion
535-525 million years ago, many phyla represented, flood
sponges
precursor to animals, collar cell- cilia and flagellum push water out of sponge and get food
animals can be characterized by
body plans
symmetry
mirror image on both sides of animal
radial symmetry
no matter where you cut it, it will always be cut in half (starfish)
bilateral symmetry
only one way to divide an animal into two halves
dorsal
back or upper surface
ventral
lower or front surface
anterior
towards the front (head)
posterior
towards the back end
cephalization
forming of head with concentration of sensory organs
median
middle
lateral
side
caudal
tail
endoderm
innermost, has archenteron, develops into digestive tract, liver, lungs, and bladder
mesoderm
all circulatory (blood, bones, muscles), kidney, repro organs
ectoderm
outermost, skin, scales, shell, exoskeleton, sometimes nervous system
diploblastic
endoderm and ectoderm only, jellyfish and coral
triploblastic
three germ layers
coelom
hollow body cavity, either fluid or air filled space between digestive tract and outer body wall
coelomates
true body cavity, normal, mesoderm on both sides of coelom
pseudocoelomates
fake, surrounded by mesoderm and endoderm, round worm
acoelmates
no coelom, flat worm
protostome development
mouth, molluscs and annelids
spiral cleavage
refers to arrangement of cells in 8 cell-stage, don’t line up
determinate cleavage
already determined which types of cells they are going to be (cannot remove one and grow new embryo)
in protostomes, coelom forms…
split mesoderm which means coelomate
archenteron
developing digestive tract
deuterostome development
second mouth, anus, echinoderms and chordates
radial cleavage
cells are aligned (8-cell stage), radial pattern
indeterminate cleavage
stem cells (remove one and it will still grow into a new embryo)
in deuterostomes, coelom forms…
folds of the archenteron
in deuterostomes, mouth is derived from
a second opening opposite the blastopore
invertebrates
lack a backbone
vertebrates
true backbone
fungus
stationary, grow on forest floor, do not photosynthesize, cell wall (chiton), heterotrophic (absorption- have hyphae which grow on what they eat, release digestive enzymes and then use hyphae to absorb food)
ecological roles of fungus
decomposers, symbiotic relationships (mycorrihizae help plants absorb nitrogen and sometimes water)
commercial uses
food (yeast- rising bread and alcohol fermentation)
antibiotics (penicillin comes from mold)
