Flashcards in Animal Origin Deck (60)
Loading flashcards...
1
Cambrian explosion
rapid diversification of animal body types & lineages
2
animal
member of major lineage of eukaryotes (Animalia)
- typically complex, large, multicellular body
- eat other orgs
- mobile
3
body plan
basic architecture of animal's body
- including: number & arrangement of limbs, body segments & major tissue layers
4
sessile
permanently attached to a substrate
- not capable of moving to another location
5
choanocytes
specialized, flagellated feeding cell found in choanoflagellates (closest related living animal relative) & sponges
- most ancient animal phylum
6
colonies
assemblage of individuals (semi-independent cells or breeding population of multicellular orgs)
7
tissue
group of cells that fcn as a unit
(ie) muscle tissue - animal or xylem tissue - plant
8
lophotrochozoans
major lineage of protostomes
- grow by extending size of exoskeletons, not molting
- many phyla = specialized feeding structure (lophophore) or ciliated larvae (trochophore)
(ie) rotifers, flatworms, segmented worms & mollusks
9
ecdysozoan
major lineage of protostomes
- grow by molting & expanding bodies
(ie) arthopods, nematodes, etc
10
segmentation
body or part of it is divided into series of similar structures
- exemplified by body segments of insects, worms, & somites of vertebrates
11
vertebrate
1 of 3 major chordate lineages (Vertebrata)
- animals w/ dorsal column of cartilaginous or bony structures & skull enclosing brain
(ie) fish, amphibians, mammals & reptiles
12
invertebrate
paraphyletic group composed of animals w/out a backbone
- includes 95% of all animal species
13
benthic
living @ bottom of aquatic environment
14
polyp
sessile stage in life cycle of some cnidarians (jellyfish)
15
medusa
free-floating stage in life cycle of cnidarians
16
cnidocyte
specialized stinging cell found in cnidarians
- used in capturing prey
17
Cambrian Explosion diversitfication
(1) increased oxygen levels
(2) predation evolution: sessile to predators w/ shells & skeleton; increased movement
(3) new riches -> new niches (ecological diversification)
(4) new genes, new bodies
18
germ layers
embryonic tissue layers
- types: diploblast & triploblast
19
diploblast
animals whose embryos have 2 types of tissue
- "two buds"
- ectoderm + endoderm
20
triploblast
animals whose embryos have 3 types of tissue
- "three buds"
- ectoderm + mesoderm + endoderm
21
ectoderm
skin & nervous system
22
mesoderm
circulatory system, muscle & internal structures (bone/organs)
23
endoderm
digestive tract lining
24
radial symmetry
"spoke symmetry"
- at least 2 planes of symmetry
- older than bilateral
- evolved from phylum Echinodermata
- attracts more prey
25
bilateral symmetry
"2 sides symmetry"
- 1 plane of symmetry (lengthwise, down middle)
- occurs in triploblastic lineages
26
cephalization
evolution of a head or anterior region
27
nerve net
nerve cells organized into diffuse arrangement
- all over body, cover everything
28
central nervous system
some neurons clustered into 1 or more tracts/cords that project throughout body
- like a tree w/ roots
29
body cavaties
enclosed fluid-filled chamber act as hydrostatic skeleton
(1) coelem
(2) pseudocoelem
(3) acoelmate
30