SDSU Biology 101 Ekdale Exam 2 Questions With Complete
Solutions
3 Layers of Triploblastic tissue Correct Answers 1. Ectoderm:
outermost layer (lining body)
2. Mesoderm: middle tissue layer (not mesoglea)
3. Endoderm: innermost tissue layer (lining gut)
Annelida Correct Answers - "little ring"
- protostome bilaterian animals; includes segmented worms
- Earliest fossils ~520 million years old
- ~15,000 living species
- marine, freshwater, terrestrial
Synapomorphies:
- Metameric segmentation
- Setae (bristles for movement)
Other features:
- Hydrostatic (fluid-filled) skeleton
- Complete gut (mouth and anus)
Annelida: Hirundinidae Correct Answers - leeches
- most terrestrial
- monoecious, but utilize in cross-fertilization
- setae absent
- clitellum, but internal
- some are either temporary or permanent ectoparasites
- anterior and posterior suckers for attachment
- can store large amount of blood
- secrete numbing and anticoagulant chemicals (hirudin)
- penetrate host's skin with proboscis or jaws, then suck blood
,Annelida: Lumbricidae Correct Answers - includes earthworms
(~3,000 species)
- freshwater and terrestrial species
- have setae, but NO parapodia
- monoecious, but use cross-fertilization
- clitellum - secretory organ, secretes mucus to form a cocoon
for fertilized eggs
- ecologically important - enrich, mix, and aerate the soil
- ingest their own weight in soil every 24 hrs
- pass 10-18 tons of soil annually
Annelida: Polychaetes Correct Answers - paraphyletic group of
mostly marine annelids
- ~10,000 species
- Setae grow from parapodia
- well differentiate head with sense organs
- some are sedentary to sessile suspension feeders
- "tube worms", live in calcaerous tubes
- food collected by tentacles
- some are scavengers
- some are motile predators with jaws
Aristotle's Lantern Correct Answers mouth part for chewing
and breaking up prey items
Arthropoda synapomorphies Correct Answers - chitinous
exoskeleton with articulated appendages
- compound eyes (multiple ommatidia)
- ommatidia are hexagonal with 6-8 light sensitive cells
- segmented bodies (tagmata, functional segments)
, Arthropoda: Chelicerata Correct Answers - 6 pairs of
appendages: 4 pairs of walking legs; 1 pair of pedipalps, 1 pair
of chelicerae
Arthropoda: Chelicerata synapomorphies Correct Answers -
"clawed"
- first pair of appendages developed as chelicerae (fang-like
jaws)
Other features:
- antena lost
- 2 tagmata
Arthropoda: Chelicerata: Arachnida Correct Answers - "spider"
- Spiders, scorpions, ticks, mites, harvestmen ("Daddy
longlegs")
- over 80,000 species, half are spiders
- 2 tagmata, breath with a "book lung", some spin silk (spiders)
Arthropoda: Chelicerata: Merostomata Correct Answers -
"thigh mouth"
- horseshoe "crabs", but aren't true crabs
- shallow marine
- carapace (shell) surrounding head
- only 5 species
- book gills
- Telson ("tail")
-
Arthropoda: Chelicerata: Pycnogonida Correct Answers -
"clustered gonads"
- "sea spiders" but aren't true sea spiders
Solutions
3 Layers of Triploblastic tissue Correct Answers 1. Ectoderm:
outermost layer (lining body)
2. Mesoderm: middle tissue layer (not mesoglea)
3. Endoderm: innermost tissue layer (lining gut)
Annelida Correct Answers - "little ring"
- protostome bilaterian animals; includes segmented worms
- Earliest fossils ~520 million years old
- ~15,000 living species
- marine, freshwater, terrestrial
Synapomorphies:
- Metameric segmentation
- Setae (bristles for movement)
Other features:
- Hydrostatic (fluid-filled) skeleton
- Complete gut (mouth and anus)
Annelida: Hirundinidae Correct Answers - leeches
- most terrestrial
- monoecious, but utilize in cross-fertilization
- setae absent
- clitellum, but internal
- some are either temporary or permanent ectoparasites
- anterior and posterior suckers for attachment
- can store large amount of blood
- secrete numbing and anticoagulant chemicals (hirudin)
- penetrate host's skin with proboscis or jaws, then suck blood
,Annelida: Lumbricidae Correct Answers - includes earthworms
(~3,000 species)
- freshwater and terrestrial species
- have setae, but NO parapodia
- monoecious, but use cross-fertilization
- clitellum - secretory organ, secretes mucus to form a cocoon
for fertilized eggs
- ecologically important - enrich, mix, and aerate the soil
- ingest their own weight in soil every 24 hrs
- pass 10-18 tons of soil annually
Annelida: Polychaetes Correct Answers - paraphyletic group of
mostly marine annelids
- ~10,000 species
- Setae grow from parapodia
- well differentiate head with sense organs
- some are sedentary to sessile suspension feeders
- "tube worms", live in calcaerous tubes
- food collected by tentacles
- some are scavengers
- some are motile predators with jaws
Aristotle's Lantern Correct Answers mouth part for chewing
and breaking up prey items
Arthropoda synapomorphies Correct Answers - chitinous
exoskeleton with articulated appendages
- compound eyes (multiple ommatidia)
- ommatidia are hexagonal with 6-8 light sensitive cells
- segmented bodies (tagmata, functional segments)
, Arthropoda: Chelicerata Correct Answers - 6 pairs of
appendages: 4 pairs of walking legs; 1 pair of pedipalps, 1 pair
of chelicerae
Arthropoda: Chelicerata synapomorphies Correct Answers -
"clawed"
- first pair of appendages developed as chelicerae (fang-like
jaws)
Other features:
- antena lost
- 2 tagmata
Arthropoda: Chelicerata: Arachnida Correct Answers - "spider"
- Spiders, scorpions, ticks, mites, harvestmen ("Daddy
longlegs")
- over 80,000 species, half are spiders
- 2 tagmata, breath with a "book lung", some spin silk (spiders)
Arthropoda: Chelicerata: Merostomata Correct Answers -
"thigh mouth"
- horseshoe "crabs", but aren't true crabs
- shallow marine
- carapace (shell) surrounding head
- only 5 species
- book gills
- Telson ("tail")
-
Arthropoda: Chelicerata: Pycnogonida Correct Answers -
"clustered gonads"
- "sea spiders" but aren't true sea spiders
