Animal Origin Flashcards
LG 14
Cambrian explosion
rapid diversification of animal body types & lineages
animal
member of major lineage of eukaryotes (Animalia)
- typically complex, large, multicellular body
- eat other orgs
- mobile
body plan
basic architecture of animal’s body
- including: number & arrangement of limbs, body segments & major tissue layers
sessile
permanently attached to a substrate
- not capable of moving to another location
choanocytes
specialized, flagellated feeding cell found in choanoflagellates (closest related living animal relative) & sponges
- most ancient animal phylum
colonies
assemblage of individuals (semi-independent cells or breeding population of multicellular orgs)
tissue
group of cells that fcn as a unit
(ie) muscle tissue - animal or xylem tissue - plant
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
ecdysozoan
major lineage of protostomes
- grow by molting & expanding bodies
(ie) arthopods, nematodes, etc
segmentation
body or part of it is divided into series of similar structures
- exemplified by body segments of insects, worms, & somites of vertebrates
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
invertebrate
paraphyletic group composed of animals w/out a backbone
- includes 95% of all animal species
benthic
living @ bottom of aquatic environment
polyp
sessile stage in life cycle of some cnidarians (jellyfish)
medusa
free-floating stage in life cycle of cnidarians
cnidocyte
specialized stinging cell found in cnidarians
- used in capturing prey
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
germ layers
embryonic tissue layers
- types: diploblast & triploblast
diploblast
animals whose embryos have 2 types of tissue
- “two buds”
- ectoderm + endoderm
triploblast
animals whose embryos have 3 types of tissue
- “three buds”
- ectoderm + mesoderm + endoderm
ectoderm
skin & nervous system
mesoderm
circulatory system, muscle & internal structures (bone/organs)
endoderm
digestive tract lining
radial symmetry
“spoke symmetry”
- at least 2 planes of symmetry
- older than bilateral
- evolved from phylum Echinodermata
- attracts more prey
bilateral symmetry
“2 sides symmetry”
- 1 plane of symmetry (lengthwise, down middle)
- occurs in triploblastic lineages
cephalization
evolution of a head or anterior region
nerve net
nerve cells organized into diffuse arrangement
- all over body, cover everything
central nervous system
some neurons clustered into 1 or more tracts/cords that project throughout body
- like a tree w/ roots
body cavaties
enclosed fluid-filled chamber act as hydrostatic skeleton
(1) coelem
(2) pseudocoelem
(3) acoelmate
coelem
fluid-filling cavity btwn inner & outer tubes
- coelemates: bilaterians w/ coelem
pseudocoelem
bilaterians that retained coelem but lost mesodermal lining in parts of coelem
- “false-cavity form”
(ie) round worms
acoelomates
bilaterians that lost coelem
- “no cavity form”
(ie) flatworms
protostome
mouth before anus development
- “first mouth”
- blocks of mesoderm hollow out to form coelem
deuterostome
anus before mouth development
- “second mouth”
- pockets of mesoderm pinch off to form coelem
gastrulation
formation of gut & embryonic germ layers
food sources
(1) detritivore
(2) herbivore
(3) carnivore
(4) omnivore
detritivore
feed on dead organic matter
herbivore
feed on plants & algae
carnivore
feed on animals
omnivore
feed on animals & plants
types of consumers
(1) predators
(2) parasites
(3) endoparasites
(4) ectoparasites
feeding tactics
(1) suspension feeding
(2) deposit feeding
(3) fluid feeding
(4) mass feeding
suspension feeder
trap suspended particles
- usually eat detritus, plankton, small orgs in currents
- (ie) sponges, clams, mussels, baleen whales, barnacles
- aka filter feeders
deposit feeder
digest organic matter in sediments
- food: sand or mud-dwelling bacteria, archaea, protists & fungi
- similar in appearance
(ie) earthworms
fluid feeder
food source: nectar
- found in wide lineages array
- often have mouth parts that allow them to pierce seeds, stems, skin, etc.
(ie) butterflies, moths, vampire bats
mass feeder
ingest chunks of food
- mouth structure correlates w/ food pieces
(ie) lions - razor teeth tare bite & snails - radula scrap
types of reproduction
(1) asexual - mitosis
2) sexual - meiosis + fusion of gamates (increase genetic diversity
where fertilization occurs
(1) internal
(2) external
internal fertilization
male insert sperm-transfer organ into female body
external fertilization
male produce sperm in packets, female picks up & inserts into own bodies
- (seahorse) female insert eggs for male body
- common in aquatic species
types of embryo development
(1) vivaporous
(2) oviparous
(3) ovoviviparous
vivaporous
nourish embryos internally; give birth to live young
- most mammals, sea stars, velvet worms, fish, amphibians
- “live bearing”
oviparous
deposit fertilized eggs; embryos nourished by yolk
- most insects, birds & animals
“egg bearing”
ovovivaparous
retain eggs internally, give birth to live young, embryos nourished by yolk inside egg
- guppies, garter snakes, reptiles & some snail
“egg-live bearing”
metamorphosis
drastic change from one developmental stage to another
- common in marine animals, insects & many amphibians
- direct & indirect
“change form”
direct metamorphosis
young adult version looks like adult version
(ie) animals
indirect metamorphosis
larvae, juvenile & adult form
- all live in diff. environment
- each stage eat diff. food
larvae
indirect metamorphosis stage 1
- embryogenesis =diff. from adults
- live in diff. habitats
- eat diff. food
juveniles
indirect metamorphosis stage 2
- look like adults
- live in same habitat
- eat same food
adults
indirect metamorphosis stage 3
- maturation
- stage of reproduction
