Download 3 Notes (Animalia I)

BIOLOGY 110
Lecture 2 (Sept. 17 2013)
J. Greg Doheny
NOTES: Kingdom Animalia I (Chapter 33)
Quiz Questions:
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Does the medusa or polyp form dominate the Scyphozoan life cycle?
Is the medusa form of the Hydrozoans diploid or haploid?
Which Phyla and sub-phyla do squids belong to?
Which Phyla and sub-phyla do slugs belong to?
What is the literal translation of ‘arthropod?’
What is the literal translation of ‘cephalopod?’
Which body structure did the syphon in the squid evolve from?
Which Phyla do the earthworms belong to?
Which Phyla do spiders belong to?
Which Phyla do centipedes belong to?
Which insect order do moths belong to?
Which Phylum do Leeches belong to?
Which insect order do mosquitos belong to?
What do you call the immature form of an insect that undergoes incomplete metamorphosis?
Give the common name for at least one crustacean.
Name one feature that distinguishes crustaceans from other arthropods.
Name one thing that is inside the ‘arms’ of a starfish.
How do humans normally contract trichinosis? (Trichinella spiralis)
NOTES:
Using MORPHOLOGICAL data, the animals are divided into Phyla as seen in Figure 32.10 (see textbook).
Using MOLECULAR data, they are divided as shown in Figure 32.11. The main difference is that the
PROTOSTOMIA are further divided into the LOPHOTROCHOZOA and ECDYSOZOA. Lophotrochozoa and
Ecdysozoa have (or used to have) hard shells or cuticles on the outside.
Phyla we’ll discuss:
Porifera (sponges)
Cnidaria
Lophotrochozoa
Platyhelminthes
Rotifera
Ectoprocta
Brachiopoda
Mollusca
Annelida
Ecdysozoa
Nematoda
Arthropoda
Deuterostomia
Echinodermata
Chordata (next lecture)
NO SYMMETRY
Phylum Porifera: (sponges). No symmetry. No true tissues. Reproduction is ‘sequential
hermaphroditism.’ Filter feeders. Suck water in through pores, into the spongocoel, waste out through
osculum. Inside spongocoel is lined with choanocytes (ciliated collar cells), which eat through
phagocytosis.
RADIAL SYMMETRY
Phylum Cnidaria: (Hydras, Jellies) Diploblastic. Radial Symmetry. Carnivores. Reproduce both sexually
and vegetatively. Polyp vs. Medusa form. One hole (mouth/anus combined). Other end sticks to rocks
etc. Sessile form (polyp) has tentacles and mouth facing upwards, aboral end sticks to rock etc. If
comes off, tentacles face downwards (medusa form) and either floats or swims. Diploid (asexual) when
in polyp form, haplid (sexual) in medusa form. Tentacles have cnidocytes (stinger cells). Some are
specialized into nematocysts (like ‘taser guns’). Venomous. Four clades:
a) Hydrozoans: polyp form dominates. Look like plants. (example: Obelia) Starvation leads to
sexual form.
b) Scyphozoan: Mushroom shaped, medusa form dominates.
c) Cubozoans: Medusa form dominates. Highly venomous. Square shape.
d) Anthozoan: Polyp form only. Forms calcified (calcium carbonate) exoskeleton. Skeletons form
coral reefs.
BILATERA (bilateral symmetry): Lophotrochozoa, and Ecdysozoa (known for shedding exoskeleton),
and Deuterostomia.
Lophotrochozoa
Phylum Platyhelminthes: (flatworms). Free living (ponds) and parasitic (inside higher animals) forms.
Triploblastic, Achoelomates. Mouth but no anus. Mouth is located on middle of ventral side.
Subgroup I: Catenulida (reproduce asexually, by budding ). Example: Planarian.
Subgroup II: Rhabditophora (reproduce sexually).
Protonephridia (network of microscopic tubules) connect inside to water environment (osmotic
potential). Has ‘eye spots’ sensitive to changes in light (movement of shadows).
a) Parasitic type I: Trematodes. Also known as ‘Blood Flukes.’ (example: Schistosoma mansoni)
Sexual and asexual forms. Live in ponds, use freshwater snails as intermediate host, and
humans (animals) as definitive hosts. Cause schistosomiasis (bladder cancer).
b) Parasitic type II: Tapeworms. Ingested in undercooked pork or beef with cysts containing eggs.
Latch onto intestine with Scolex (head with hooks and suckers) and grows to large size (10
meters). Re-enter blood. Ribbon-like body composed of proglottids produces eggs, secreted in
feces. Feces contaminates water or soil, animals eat.
Phylum Rotifera: Sexual and parthenogenic reproduction. Has ciliated mouth and alimentary canal.
Phylum Ectoprocta: (bryozoans): Look similar to hydras. Produce coral reefs with calcified exoskeleton.
Has U-shaped alimentary canal. Mouth and anus near same place.
Phylum Brachiopoda: (‘lamp shells’) Have two shells like bivalve mollusks, but shell valves are on dorsal
and ventral side, not left/right. Tentacles.
Phylum Mollusca: (snails, slugs, oysters, clams, octopuses, squids) diverse group of coelomates that look
different, but have same original body plan. All have a foot (for motility), a visceral mass (contains
organs), a mantle (tough tissue that covers the visceral mass) that secretes the exoskeleton (shell)
material (some mollusks have lost their ability to make a shell), a mantle cavity (sometimes used to
store water or air), and a radula (toothed tongue used for eating). Shell (if present) forms from
reinforcement of the exoskeleton by calcium carbonate. Have permanent sexes (sexual reproduction),
and a ciliated larval stage called a trochophore. Seven or eight clades are known (still debating about
how many!). We’ll discuss four of them.
a) Chitons: oval body with eight dorsal plates.
b) Gastropods: (snails, slugs, abalone, limpets). Algae or suspension feeders. Some are carnivores
(ie-the Cone Snail. Secretes nerve paralyzer, radula is modified to cut through shells of other
organisms.)
c) Bivalves: (Clams, oysters, mussels, scallops.) Bivalve ‘two shells.’ Radula has been lost, so they
are suspension feeders. Cilia sweep food particles from the gills to the mouth.
d) Cephalopods: (literally ‘head-foot’) Octopus, Squid, Cuttlefish, Nautilus. Carnivores with
tentacles (often containing hooks), eyes, brains. Foot has been modified to form the siphon
(squirts water for propulsion). Nautilus is only one that hasn’t lost its ability to make a shell.
Largest squids (ie-Architeuthis dux) can be 5 meters long!
Phylum Annelida: (‘little rings’). Soft, segmented worms, including earthworms and leeches.
Coelomates. Segmented worms. Two types: a) Polychaetes (‘many legs’) and b) Oligochaetes (‘few
legs’). In polychaetes, each segment has two parapodia (feet) attached. Each foot has many chaetae
(hairs made of chitin). In oligochaetes, only a few legs/hairs are present, and are very small. Both have
mouth, anus and alimentary canal. Have a closed circulatory system (not open to outside.) Are
hermaphrodites, can mate with each other, or reproduce by fragmentation (break in half and re-grow
the other half).
Ecdysozoa (shed cuticle, or molt)
Phylum Nematoda: (Roundworms). Pseudochoelomates, thin posterior end. Tough cuticle. Sexual
reproduction. Some are parasites. Ie-Trichinella spiralis causes trichinosis. Form cysts (full of eggs) in
undercooked meats (especially wild meats like bear, moose etc.). Adults mate in intestine, female
burrows through to lymphatic ducts, travel to muscle fibers and make more cysts.
Phylum Arthropoda: (arthropods. Arthro=’articulated’ or jointed. Pod=’food’ Arthropods=’jointed
foot.’) Have segmented body and large legs. Usually six legs, but some have been modified to form
claws, antennae, mouth parts etc. Four major subgroups.
a) Chelicerates: (spiders, scorpions, ticks, horseshoe crabs, sea spiders). Have chelicera (fangs)
mouth and two pedipalps (used for feeling and mating). Have Cephalothorax (head and thorax
combined) and Abdomen (unlike some arthropods that have a complete head, thorax and
abdomen). Heart. Book Lungs. Subgroup: Arachnids (scorpions, spiders, ticks). Usually only
four ‘true legs.’ Others are developed into pedipalps, claws etc.
b) Myriapods: Centipedes and millipedes. Have long antennae and mouth mandibles.
c) Hexapods: (‘six legs’) ‘INSECTS.’ Some have developed flight (wings). Usually have two pairs of
wings, but sometimes one pair has developed into a shell or a pair of halteres (for balance).
Have segmented head, thorax and abdomen, but head segments are fused. Have compound
eyes and mouth mandibles. Some have open circulatory system, tracheal network (chitin tubes)
that carry oxygen to body from pores (no lungs). Can be divided by complete metamorphosis
(larval stage enters a cocoon and emerges as a completed adult) vs. incomplete metamorphosis
(goes through a series of smaller versions of the insect [nymphs] that molt). 30 different insect
orders, we’ll discuss eight.
i)
Archaeognatha: (bristle tails), live in bark of trees.
ii)
Thysanura: (silver fish)
iii)
Coleoptera: (beetles). 2 pairs of wings, one is a protective shell for the membranous
wings.
iv)
Diptera: (Flies and mosquitos), mouth (proboscis) is adapted for sucking. Two pairs of
wings, one pair adapted to halteres.
v)
Hymenoptera: Social insects (bees, wasps, ants), 2 pairs of wings, one pair halteres.
vi)
Lepidoptera: Moths. Proboscis is for sucking nectar.
vii)
Hemiptera: incomplete metamorphosis (nymphs). 2 pairs of wings, one is leathery
cover.
viii)
Orthoptera: Grasshoppers, crickets. Incomplete metamorphosis. Have wings but can’t
fly. Large hind legs adapted for jumping.
d) Crustaceans: Crabs, lobsters, crayfish, shrimps, barnacles. Exoskeleton is hardened with calcium
carbonate. Only arthropods with two sets of antennae. Only arthropods with appendages
(legs) on the abdomen.
i)
Isopods: land crustaceans (pill bugs).
ii)
Decapods: (lobsters, crayfish, shrimp, crabs.)
iii)
Copepods: small, planktonic crustaceans (ie-Krill).
iv)
Barnacles: have appendages inside the shell.
Deuterostomes: Echinodermata and Chordata.
Phylum Echinodermata: ‘Spiny skin’ (starfish, sea stars, sea urchins, sea cuccumbers). Have a water
vascular system, pores called madreporites open to water outside. Have ‘tube feet,’ central mouth and
stomach. Arms of starfish contain digestive glands (four arms) and gonads (the fifth arm). Four
subdivisions.
a) Asteroidea: sea stars, sea daisy (lacks arms)
b) Ophiuroidea: brittle stars (longer arms)
c) Echinoidea: sea urchins and sand dollars. Have five ‘arms’ of tube feet collapsed into a spherical
body.
d) Holothuroidea: Sea cucumber. Have five ‘arms’ of tube feet collapsed onto a pickle-shaped
body.
PRACTICE QUESTIONS:
Consider the following phyla:
a)
b)
c)
d)
e)
f)
g)
Porifera
Cnidaria
Platyhelminthes
Rotifera
Ectoprocta
Brachiopoda
Mollusca
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Which are capable of reproducing through sequential hermaphroditism?
Which are capable of reproducing through budding?
Which contains the snails?
Which contains the insects?
Which contain the parasitic ‘blood flukes?’
Which have a water-based vascular system?
Which have a dorsal tube filled with nerves?
Which Phylum contains the Lampshells?
Which Phylum contains the Leeches?
Which contains the Hymenopteras?
Which are capable of reproducing through fragmentation?
Which are capable of sexual reproduction?
Which contains the order Lepidoptera?
Which are asymmetrical?
Which have radial symmetry?
Which are the ‘flatworms?’
Which have bilateral symmetry?
Which alternate between a polyp and medusa form?
Which form coral reefs?
Match the terms to the definitions:
a) Aboral
b) Anthozoan
c) Compound
d) Chelicerae
e) Choanocyte
f) Hymenoptera
g) Lepidoptera
h) Madreporite
i) Mandibles
j) Medusa
h)
i)
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n)
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p)
q)
r)
s)
Annelida
Ecdysozoa
Nematoda
Arthropoda
Echinodermata
Chordata
Nematocyst
Nymph
Orthoptera
Osculum
Polyp
Proglottid
Scolex
Spongocoel
Syphon
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Large opening in a sponge, leading out from the digestive cavity.
Type of eyes that insects have.
An order of social insects, including bees and wasps.
Cnidarian that only exists in the polyp form, and forms coral reefs.
Segment of a tapeworm’s body.
Opening in the skin of an Asteroidea, leading to its water vascular system.
The immature form of an insect that results from incomplete metamorphosis.
Tiny arms surrounding the mouths of Myriapods.
The head of a tapeworm.
An order containing the moths.
‘Fangs’ used by spiders.
Part of an octopus or squid used for propulsion.
The stinging cell of a Cnidarian.
The end of a polyp (Cnidarian) that attaches to rocks or the ocean floor etc.
The sessile form of a Cnidarian
The interior compartment of a sponge.
The free living form of a Cnidarian
Ciliated ‘collar cell’ in a sponge.