Animal Biology Exam 2

MAF sponge type

Microciona aggregation factor

HAF sponge type

Halichondria aggregation factor

FAF sponge type

Ficulina aggregation factor

Phylum Porifera (5000-10,000 species)

• Class Demospongiae

• Class Calcarea

• Class Hexactinellida

Phylum Placozoa 6

• Trichoplax adhaerens

• Multicellular

• Lack tissues

• Highly mobile and flexible

• May be basal metazoans

• Between 3 and 100 species

Asconoid

simple and continuous

Syconoid

moderate folding

Leuconoid

intricate subdivisions

Steps for the water flow in sponges

Water → Ostium of porocyte → Sponocoel → Osculum

Phylum Porifera Class Demospongiae 4

• Largest class of sponges

• Primarily leuconoid construction

• Lack CaCO3 in their skeleton

• All freshwater sponges

Phylum Porifera Class Calcarea 2

• Spicules composed entirely of CaCO3

• Asconoid, Syconoid and Leuconoid construction all present

Phylum Porifera Class Hexactinellida

• 6 rayed siliceous spicules

• Syconoid or leuconoid

• No pinacoderm

What’s a sponge’s synapomorphy?

Choanocytes

Choanocytes 3

• Flagellated cell lining the spongocoel

• Generate currents for feeding/waste removal/reproduction

• Innermost layer of cells

Pinacocytes

Line epidermis (pinacoderm)

Porocytes

Perforate epidermis and are sites of ostia

Solenocytes

Secrete calcareous or siliceous spicules

Spongocytes

• Produce spongin (made of collagen → metazoan synapomorphy)

• Shared ancestral traits is sympleomorphy

What is collagen the synapomorphy of?

Metazoans

Spongocoel

• Lined by choanocytes

• Perforated by porocytes

• Not a true coelom

• Water filled cavity

Mesohyl

• Not a cavity but a mass of nonliving “tissue”

• Contains living cells between pinacoderm and the spongocoel

Archaeocytes

Stem cells

Sponge functions

• Movement

• Immune system

• Carnivory: long spicules, critters get impaled, sponge has cells that grow over top of little crustacean

• They don’t have a traditional nervous system

What do sponges have instead of a traditional nervous system?

• Have true nerves but not CNS

• Nerve net with two nerve networks

• Slow: many non polar nerve cells signals travel any direction

• Fast: less branched, bipolar, greater diameter

• Larger nerves signal faster: space for signal to move along axon. Quicker for big group to get out of big door than small

• Neuroid cells

Neuroid cells

Gene expression similar to synapses sending signals, digestive cells with expression similar to synapses receiving signals

Sponge reproduction

• Hermaphrodites

• Sexual reproduction - internal fertilization (choanocytes capture and transport sperm to the eggs)

• Non feeding larvae

• Swim for less than 1 day

• Asexual reproduction - gemmule production. Take stem cells, package them up, thrown into water, nest until spring. Happens with stress.

Phylum Cnidaria (subphylum + classes)

• Subphylum Medusozoa

-Class Scyphozoa

-Class Cubozoa

-Class Hydrozoa

• Non medusozoans

-Class Anthozoa

Synapomorphies of Phylum Cnidaria

• Nematocytes (stinging cells, cnidae)

• Planula larva

How do nematocytes work?

• Chemical/physical stimulus to cilia triggers firing

• Trigger if something touches at the top

• Spines and barbs rupture the operculum after change in osmotic pressure

• Single shot/nematocyst

• Specialized for stinging, penetrating or secreting toxins

• Paralyze prey with stinging and stick to them and pull back in.

Class Scyphozoa (ph cnidaria)

• True jellyfish

• 125 spp

• Named for thick, gelatinous layer of nonliving material between tissue layers: mesoglea

What similar structures did sponges have that class Scyphozoa has?

Mesohyl

Scyphozoa medusa: digestion and reproduction (ph cnidaria)

• Food goes in the mouth → pouches → seals for storage and digestion → secreted through mouth (no anus)

• Branching canals needed for digestions and excreting waste

• Gonads lining gastro pouches

• Usually one gender

Scyphozoa medusa: rhophalia (ph cnidaria) 3

• Eye (light + dark)

• Navigating by tilt

• Nerve signal to squeeze certain ways

Scyphozoa life cycles (ph cnidaria)

• Sexual with gonads

• Asexual strobilation - scyphistomas polyps

• Ramets clones because came from the same polyp

• Sexual recombination in adults

Class Cubozoa (ph cnidaria) (7 things)

• Box jellyfish

• Complex eyes with lenses

• Small: a few cm long

• Highly toxic nematocytes

• Primarily consume fish

• Can be fatal to humans

• Only 20 species, primarily in the Pacific

Box jellies (Class Cubozoa (ph cnidaria))

• At surface they can look into air. Can look into water. Use lenses to see different liquids.

• Lense eyes (color, movement, shapes, mazes)

Class Hydrozoa (ph Cnidaria) (5 things)

• Polyp phase dominates life cycle

• Medusae are much smaller than “true” jellies

• Nematocysts restricted to epidermis

• Around 3000 species

• Orders Hydroida and Siphonophora

Class Hydrozoa Order Siphanophora

• Gonozoids - reproduction

• Gastrozoids - digestion

Class Hydrozoa Life Cycles

• Differentiated polyps to have different functions (food, reproduction, defending). But some genetic individual.

Class Hydrozoa Hydrodia Medusoid stage

• Velum

• Moves faster than squeezing bell and opening closes up and is smaller so water goes through faster and farther (like hose on brother)

Class Anthozoa (ph Cnidaria, non mezazoan) 7

• 6000 species (largest class of cnidarians)

• All marine and polypoid

• Mesentary: increase surface area as they get bigger. Bring in food as much as possible. Helps them keep nutrients. Any food they don’t eat has to be puked up.

• No mesoderm (not true coelom)

• Has body cavity

• Pseudocoelomate

• Stinging cells = nematocysts

Class Anthozoa Behaviors 6

• Stinging cells = nematocysts

• Stomphia swim response

• Acrorhagi as weaponry in Cnidarian warfare

• Anemone make big colonial groups

• Fight for space on a rock

• Different jobs in the colony (defense, reproduction, scouts)

Cnidarian digestion and waste removal

• Cnidarians are carnivores

• Digestion initially extracellular in GVC. Completed intracellularly in vacuoles

• Lack of an anus means waste is expelled through the mouth

Cnidarian reproduction

-Medusoid form in Scyphozoa and Hydrozoa

-Anthozoans develop into planula larvae from sperm and eggs released during spawning events

Satiate predators: not all eggs will die

Phylum Ctenophore 8

• 150 species, all marine

• Comb rows = plates of fused cilia. Helps them move.

• Colloblasts

• Nerve nets similar to Cnidarias

• Superficial similarity to jellyfish but have the mesoderm (triploblastic) and biradial symmetry

• Digestion and waste removal

• Anal pores

• Gelatinous but small

Colloblasts

• Sticky granules, stick to things rather than sting

• Ctenophores

What’s the synapomorphy of phylum Ctenophora?

Colloblasts

Ctenophore Reproduction

• Simultaneous hermaphrodites

• External fertilization

• Cydippid larvae even in groups that lose tentacles later in ontogeny

• But cydippid “larvae” turn out not to be larvae at all

Ctenophore behavior 4

• Nemeopsis (prey)

• Beroe (predator)

• Prey preferences

• Devastate fisheries

Which fluid is denser, water or air?

Water

Which fluid is more viscous, water or air? (viscous is fluid resistance to flow)

Water

What physical measurement other than density and viscosity is needed for calculating Re?

Velocity

Which organism would have the lowest Reynolds number?

a) Whale swimming

b) Eagle flying

c) Sperm swimming

d) Human walking

c) sperm swimming

Which of the following has the lowest Reynolds number?'

a) Human swimming in tarter sauce

b) Human swimming in olive oil

c) Human swimming in tar

Human swimming in tar

What is the Reynold’s number?

• increasing speed, pipe diameter, density of fluid

• decreasing viscosity of fluid

• Low: slow/heavy

• High: fast/humans

• Humans are fast but can simulate low Reynolds number

• Relative size fluid is viscous (for animals we think it’s easy for)

Ratio of inertial forces to viscous forces

p = density

l = characteristic length

v = velocity of fluid relative to the organism

u = dynamic viscosity of the fluid

Non-Slip condition 8

• Fluid mechanism stating that a fluid in contact with a solid surface moves at exactly the same velocity as that surface

• How dust and grime accumulate on a fast moving fan. Not moving, stuck on first layer.

• Takes space to get from 0-100

• You move as fast as obstructing current as you go up in space

• No fluid movement at ground level. Takes multiple plates to get up to water at current.

• Important for little critters. Food is up so not getting to them. Want to get passed boundary layer where not moving

• Anemones get tall/skinny to reach food and waste goes into current

• Lophophores stick up into air with feather like structure

What is a hydrostatic skeleton and how does it work?

• Skeleton that relies on fluid pressure

• A fluid filled cavity (often called a coelom) surrounded by muscles that alternate between contraction and relaxation of different muscle sets to allow the organism to change its shape and move.

• Common muscle fiber arrangements. There are different types of muscles that squeeze

• Collagen fibers

• Bunch of animals use them

Collagen fibers

• A metazoan synapomorphy

• Key to allowing bending and not kinking

• Cross fiber at angle helps with stretching and getting longer or fatter without kinking

• 2 antagonistic sets of muscles. Can’t shrink and such by itself, you have to antagonize it

• Water allowing it to happen

• Sphincter/radial controls water intake and outtake. Expand and contract to open hole. Ciliary action is how they get water in. Sphincter and radial are always opposite. Sphincter relaxed lets water in

• Transition A - It wants more volume. Contract radial, relax sphincter and use ciliary action to let water in. Relax circular muscles to let it expand

• Transition B - Keeping some volume of water. Relax radial muscles, contract Sphincter. Contract circular muscles. Relax longitudinal.

• Transition C - Relax Sphincter. Contract radial. Contract longitudinal and circular muscles

• Transition D (from the end to the start) - Keep sphincter open, keep radial contracted. Use ciliary action to pull water in. Slightly contract circular and relax longitudinal.

Why would an anemone want to stretch out to become tall + skinny 6

• At surface of rock there’s no flow (no slip). Further up, faster the flow. Little flow for diffusion when near rock

• Out of boundary: increase access of food and more oxygen

• Frills increase surface area

• Reproduction: carries gametes further

• Swim/float further

• Increases waste removal

Why would an anemone want to get short and fat?

• Avoid getting eaten

• Maybe too strong velocity and you’d get ripped off the rock

How does a hydrostatic skeleton permit an earthworm to crawl? What role does metamerism (segmentation) play?

• Fluid pressure/muscle contractions

• Septa: allow one segment to change shape without changing the other

• To get short/fat: contract longitudinal (shorter), relax circular (fatter)

How does a hydrostatic skeleton permit a sea urchin or sea star to crawl?

• Collagen prevents kinking

• Tube foot can change shape without affecting the other foot

• With no more fluid to get longer it’ll relax the longitudinal muscles

• Mostly don’t release water but an open one allow water to be pushed

How does a hydrostatic skeleton of a soft shell crab allow it to crawl?

• Protozoans

• Ecdysozoa

• Occurs after a molt

• The skeleton is a complex water balloon shape using pressure in body to create force for walking and such

• Use it for parts of life cycle but still counts exoskeleton and hydrostatic skeletoon

Lophotrochozoa

Lopho: alofore feeding structures

Tropho: larval form trophophore

• Since flatworms don’t have feeding structures they need that larval stage

Phylum Acoelomorpha 8

• Small (untrue) flatworms

• Bilaterally symmetrical and superficially resembling flatworms

• Phylogenetic placement contentious, but generally assumed as sister to remaining bilateral

• 350 spp typically marine and benthic

• Triploblastic

• Acolomate

• Reduced complement of Hox genes

• Unique type of cleavage. Duet spiral cleavage.

Phylum Platyhelminthes 9

• Class turbellaria

• Class Cestoda

• Class Tremetoda

• Triploblastic - mesodum

• Acoelomate

• Bilaterally symmetrical

• Cephalization

• Organs + organ systems

• No synapomorphies

Class Turbellaria (ph Platyhelminthes) 5

• 3000 sp

• Most are free living

• General less than 1cm (up to 30cm)

• Locomotion using pedalwaves

• Duo-glands required

Dougland system

• Helps flatworms attach and unattach

• One of them is sticky and one of them is unsticky

• Used for locomotion

Regulation in Planaria

1. Train planaria to find a foot source

2. Decapitate their head above the pharyx (red arrow) removing their brain

3. Allow head to regrow

4. Test planaria ability to find food

5. Result: just as good as animals that kept their head

6. Conclusion: memories can be stored and retrieved from outside of the head

Excretion in Turbellaria

Beating of cilia

Class Cestoda (ph Platyhelminthes) 7

• No mouth

• Endoparasitic

• Scolex used for attachment

• Proglottids for reproduction

• 5000 spp

• Tape worms

• Hundreds of thousands of eggs per day per cestode

Class Trematoda (ph Platyhelminthes)

• 8000 sp

• Entirely parasitic

• Most are digenean “two births”

• Requires multiple intermediate hosts (snail and fish to human)

• Some of the most complex life cycles of all metazoans

Class Trematoda (ph Platyhelminthes) Lancet Liver Flukes

• Hypnotists to the invertebrate stars

• Ants as as intermediate hosts are directed to clamp down on the tips of grass blades to increase likelihood of consumption by grazers (final hosts)

• Temperature dependance in the switch

• Just one fluke controls the brain but tends to die in the next host. Single organism sacrifices itself for clonemates to survive

The Lophophorate Phyla. What’s a lophophore?

• A circumoral body region characterized by a circular or U shaped ridge around the mouth bearing 1-2 rows of hollow, ciliated tentacles

• The internal space is a coelomic cavity and the anus lies outside of the tentacles.

What’s a lopho for?

• Gas exchange (and waste removal)

• Food collection

Shared characteristics of Lophophorates (symplesiomorphies) SBSU

• Sessile

• Benthic

• Suspension feeders

• U-shaped gut

Traditional view of Lophophorates

Current view of Lophophorates

Phylum Brachiopoda

• Class inarticulata

• Class articulata

• Bivalved shell secreted by mantle tissue

• Valves are dorsal and ventral (cf with bivalve molluscs)

• Entirely marine

• 350 extant spp

• Individual free living bivalves that aren’t molluscs

Phylum Phoronida

• 15-20 spp

• Benthic, tube-building, suspension feeding worms

• 10-12cm long

• Highly modified brachiopods

• Water flow through phoronid lophophore

• 3 part body plan

• Feathery at top

Metamorphosis in phoronida (takes 15 minutes)

Phylum Bryozoans

• “moss animals”

• 5000 spp

• Colonies produced by asexual reproduction

• Basically floating mouths

• “overwinter” when it gets cold. Similarto gammules in phyla profiera (resting stage). Avoid bad environmental conditions

• Class Phylactolaemata (freshwater)

• Class Gymnoloemata

• Class Stenolaemata

• How splits influence

• Outgroups

• Differences that are synapomorphies

• Collagen - multi = metazoans

• Triploblastic/comb synapomorpy of ctenophore

• Not all sponges are triploblastic but ctenophore is