Animals II Flashcards
1
Q
Characteristics of bilaterians
A
- Triploblastic
- All form true HOX genes –> highly conserved (in segmented animals, they control the type of appendages formed in each segment)
2
Q
Protostome groups
A
Lophotrochozoan = characterized by filter feeding structure- lophophore- and/or cilia-bearing larvae -trochophores (lophophorates not monophyletic)
Ecdysozoans = cuticle covers body and molts periodically for growth
3
Q
Lophotrochozoan gps
A
- flatworms
- rotifers
- annelids
- mollusks
- bryozoans
- brachiopods
- phoronids
- ribbon worm
4
Q
Arrow worms
- phylogeny
- coelom
- sex
- feeding
A
- used to be considered duterostomes (blastopore becomes anus and radial cleavage of zygote)
- develop coelom like protostomes
- basal protostome gp, prob sis to lophotrochozoans
- good model for ancestral bilaterian
- coelomate, but very simplee with nocirculatory or waste removal systems
- hermaphroditic
- marine: plankton predator
5
Q
Arrow worms
- phylogeny
- coelom
- sex
- feeding
A
- used to be considered deuterostomes bc blastopore becomes anus and radial cleavege of zygote
- develop coelom like protostomes
- now thought to be basal protostome and prob sis to lophotrochozoans
- coelomate, but very simple with no circulatory or waste removal systems
- hermaphroditic
- marine–> plankton predators
6
Q
Bryozoans
- def
- feed
- envirion
- first fossils
A
- along with entoprocts are colonial sessile animals made of many dif individuals (zooids), some of which secrete tubular housing of chitin, proteis, CaCO3
- coelomate
- filter feeders W/ lophophore
- 4000-4500 species
- dif from entoprocts in placement of anus –> theirs is outside ring or tentacles, but entoprocts are inside
- mostly tropical marine, some freshwater
- fossils f/ ordovician, but soft bodies ones prob b4
7
Q
Platyhelminthes
- coelom
- feeding
- environ
- anatomy
A
- 25,000 species
- structurally simple –> acoelomate
- marine, freshwater, terrestrial
- over 50% parasitic
- cephalization w/ anterior ganglion
- true gastrulation absent, but all 3 embryonic tissues present
- no complete gut –> intestine is a sac simlar to gastrovascular cavity of cnidaria
8
Q
Platyhelminth gps
A
turbellaria
monogenea
trematoda
cestoda
bottom 3 are only parasitic; each is monophyletic; prob their own monophyletic sis to nonparasitic ones
9
Q
Turbellaria
A
- “planaria”
- mostly free living predators and scavengers (16% of platyhelminth species)
- part of Acoela (gp that divered b4 bilaterians and are goo at regenerating)
- even small pieces can regenerate whole animal
- no senescence
- under control of specific master control gene regions
- came back from space two-headed
10
Q
Bipalium
A
- land planarians
- among biggest flatworms (up to 20”)
- hermaphroditic
- predators –> eat earthworms
- Native to Asia, but introduced elsewhere
- some are important invassive introduced species
11
Q
Monogenea
A
- ectoparasites of (mostly) fish (one known from mammal)
- hermmaphroditic
- simple life cycles
- well-developed attachment structures
12
Q
Trematoda
A
- flukes
- obligate parasites
- most (except schistosomes) are hermaphroditic
- attach to host with suckers
- often have separate intermediate and final hosts (gastropod then vertebrate)
- lots of human parasites
13
Q
Schistosoma
A
- trematoda
- causal agent of schistosomiasis
- affects 200 mil ppl worldwide –> worst parasitic disease besides malaria
- causes pain, anemia, dysentery
14
Q
Clonorchis
A
- liver fluke
- third most prevalent worm parasite of humans
- in japan, china, taiwan
- infect snails, then fish
- humans get it from raw fish
- live in lier for up to 30 yrs
15
Q
Cestoda
A
- tapeworms
- internal parasites
- vertebrate hosts (can be in ANY vertebrate)
- complex life cycle with many hosts and larva hosts
- host specificity variable, but highest in adults
- scolex with hooks or suckers
- no digestive system
- proglottids = reproductive sacs
16
Q
Diphyllobothrium
A
- fish tapeworm
- infects fish and mammals
- humans come in contact with it by eating raw fish
- usually symptomless or mild symptoms
17
Q
Cestoda proglottids
A
-fertilization results from outcrossing with other worms, although some proglottids can exchange gametes with each other
18
Q
Rotifers
A
- microscopic multicellular organisms with complete gut and relatively complex internal anatomy
- pseudocoelomate
- ciliated corona “wheel” captures food
- most are sexual, but bdelloid rotifers have been parthenogenetic for mills of years
19
Q
bdelloid rotifers
A
- survive stresses by entering dehydrated dormant state –> recover when wet
- can incorporate foreign DNA (even from food) during recovery
- suggests a novel form of genetic recombo that substitutes for sexual reproduction (tardigrades do something similar)
20
Q
Ribbon worms (nemertea)
A
- look like flatworms, but are coelomate with complete gut and closed circulatory system
- mostly marind; some freshwater and terrestrial
- predators with specialized probiscus in hollow rhynchocoel that can be extruded to kill or immobilize prey
- regenerative capacity
21
Q
Brachiopods
A
- 350 living species; 30,000 extinct
- extensive fossil record –> f/ cambrian
- useful in identifying geologic strata
- filter feeding species with prominent lophophore
- coelomate
- dorsal/ventral valves in contrast to R/L valves of mollusk bivalves
22
Q
Annelids
A
- 16,500 species
- Classes: Polychaeta (marine; many bristles), Oligochaeta (terrestrial; few bristles); Hirudinae (freshwater; no bristles)
- coelomate
- asexual reproduction thru fragmentation or regeneration
- hermaphroditic or dioecious
- centralized nervous system and complete digestive system
23
Q
Oligochaeta
A
few bristles
aquatic or terrestrial
earthworms
clitellum = permanent sexual organs
24
Q
polychaeta
A
mostly marine
free living
many bristles
no permanent sex organs
bristle worms, fan worms, bloodworms, beardworms that live at deep sea ocean vents
25
Q
Hirudinea
A
Mostly freshwater leeches -parasitic or predatory or scavengers -flat with reduced segmentation -often lack chaetae -prominent suckers -secrete anticoagulant- hirudin
26
Q
Other annelid gps
A
- echiura (spoon worms)
- sipuncula (peanut worms)
- both inglude unsegmented, marine detritivores
- each was considered a separate phylum, but recently added to annelida
27
Q
annelid segmentatio
A
- specialized subunits = metameres
- each portion or the coelom is partitioned–> repeat itself
- greater precision of movement
- simple mode of size increase
- arisen several times independantly (in deuterostomes too)
28
Q
Mollusks
A
- 10,000 species
- very diverse
- coelomate
- great range of aquatic habits; some terrestrial
- all have foot, visceral mass, and mantle (but dif gps elaborate on these strutures)
- have chitinous radula (may be reduced)
29
Q
mollusk classes
A
bivalvia
gastropoda
polyplacophora
cephalopoda
30
Q
Bivalva
A
- 2 halves hinged at mid-dorsal line (R/L)
- flat shell, reduced head, paired gills
- most are suspension feeders
- 9% are hermaphroditic
- mantle forms siphons
- marine and freshwater
- clams oyesters, scallops, mussels
31
Q
Scallop eyes
A
- up to 200 in fleshy tissue under shell
- not like camera lens type in cephalopod
- each has 2 retinas and mirrors that focus image on 1 retina or other
- mirrors are made of many layers of tiled guanin crystals stacked on each other
- one retina is sensitice to dimmer light coming in at an angle, and the other captures movement in bright light
32
Q
Gastropoda
A
- most divers mollusk gp ~85,000
- TORSION = rotation of visceral mass
- head with eye stalks
- shell sometimes reduced or absent
- foot for locomotion
- hermaphroditic
- marine, freshwater, and terrestrial
- snails, slugs, limpets, nudibranchs
- mantle is modified lung in terrestrial slugs/snails
33
Q
Gastropod torsion
A
180 degree twisting of visceral mass during embryonic dvlpmnt
- head and foot stay in place
- mantle cavity and anus moce to anterior
- synapomorphy for gastropods
- unclear if it’s adaptive–> may have helped pull head into mantle cavity
34
Q
jorunna parva
costasiella kuroshimae
A
-marine, shell-less gastropod
leaf sheep ni=udibranch
35
Q
venomous cone snails
A
- over 50,000 neurotoxic peptides
- fish-hunting snails -> dangerous to ppl
- hypodermic-like radula tooth and venom gland
- conotoxins are used to study ion channel func –> target specific receptors
- source of novel therapeutic drugs for alzheimers, parkinsons, and epilepsy
36
Q
polyplacophora
A
- chitons
- 8 plate hinged shell
- foot for locomotion, but moves super slow
- no head
- radula scrapes algae from rocks
- marine
- mostly gonochoristic (seperate sexes)
37
Q
Cephalopoda
A
- reduced or internal shell
- closed circulatory system
- head (modified foot) with grasping tentacles
- radula may be absent
- siphon formed from foot allows locomotion thru jet propulsion
- 800 spp –> all marine predators
- no hermaphroditism or sex reversal
- squids, octipi, cuttlefish, chambered nautiluses
38
Q
Cephalopod behavior
A
- active, intelligent with big brains and complex nervous system
- well-developed sensory organs
- vision similar to vertebrates –> camera lens eye
- eyes a good example of convergent evolution
- remarkable ability to change color, but most are color blind
