Protostomes

Through gut

Two holes - 1 for taking in food, 1 for expelling waste

Advantages:

1. allows for continuous eating (dont have to poop out old food before eating new food)

2. prevents reingestion of waste

3. specialization of digestive structures

Nephrozoa

Through gut animals (all animals other than the porifera and cnidaria)

1. Through gut

2. Bilateral symmetry

3. Coelom

Coelum

Fluid filled pouch between gut and ectoderm

Forms early in development

To house and organize internal organs for COMPLEXITY

Nephrozoan development

Start as a blastula (hollow ball 1 cell thick)

Triples in thickness

hole is punched through blastula -> called gastrula

Hole punched through other side to form digestive tract

Protostomes

mouth first development

Spiralia

1. Platyhelminthes (flatworms)

2. Mollusca (molluscs)

3. Annelida (segmented worms)

Flatworms

Secondary loss of the through gut in some cases

No respiratory system, circulatory system

Flat bodies to exchange gas with water

Has flame cells: can pee

- waste + water, excretes through skin or bladder

- allow to get thicker

Brain: nervous system allow to adjust their activity to their environments

- cephalization

- simple, but enough to avoid predators and chase prey

Cephalization

concentration of sense organs and nerve cells at the front of an animal's body (head)

Penis fencing

where two flatworms fight each other (during sex) over who will carry the baby -- each one doesn't want to carry it because they would have to find extra materials to feed it

Annelids

segmented worms - earthworms

Segments separated by internal walls - septa

Some segments specialized

Feeding:

-Crop (storage)

- Gizard (grinder)

- Intestine (digestion)

- Anus (pass waste)

Respiration: some have gills, or through skin (has cuticle to prevent drying out

Internal transport: closed circulatory system (blood in vessels)

- 2 main blood vessels (dorsal, ventral)

-Ring vessels that pump

Excretion: 2 kinds of waste

- anus -> solid

- cellular metabolism -> nephridia

Response: well developed nervous system

- ventral nerve chord - small ganglia

- sensory tentacles, chemical receptors + eyes

Movement + reproduction

- some budding

- separate sexes, some hermaphrodites

- external fertilization

- clitellum - when eggs ready, secretes mucus ring into which eggs/sperm released

Mollusca (molluscs)

Sister to the annelids

1. Radula (tongue, but covered in teeth)

2. Foot (muscular structure for movement)

3. gills (exchange oxygen and CO2 w/ water)

4. Mantle (soft tissue that encloses molluscs reproductive, breathing structure. secretes mollusc shell)

Types:

- Chitons (polyplacophora)

- Cephalopods

Chitons (Polyplacophora)

Small molluscs w/ segmented shells

Feed off of algae, anything that they can scrape off rocks with radula

Cephalopods

Main adaptations:

1. Foot -> complex feeding structure

- Long arms grab food

- short Tentacles bring food to mouth

2. Mantle -> hollow jet propulsion system

-Fill with water, eject through Siphon

Some have kept their shells, others repurposed as beak

Eyes: Complex camera style eyes with NO blind spot

Nervous system: Highly complex

-Cephalized, but less than humans

- 1 central ganglion, many smaller ganglia in limbs

Colour changing: covered in chromatophores

Gastropods

snails and slugs

Torsion - bodies twist around, leaving anus over the head

Body structure: highly cephalized, variety of sensory organs on head

- Eyes from simple cup eyes to complex camera style eyes

Reproduction: Mostly hermaphroditic - competitive mating like flatworms

- shoots other with "love dart"

Bivalves

mollusks that have two shells held together by hinges and strong muscles

Foot adapted to anchor animal

Filter feeders

Anatomy:

Reduced nervous systems

Draw water into mantle through INCURRENT siphon, out through EXCURRENT siphon

Open circulatory system

Movement: free swimming larvae, sessile as adults

Ecdysozoa

Nematoda (roundworms) and arthropods

Most successful group of animals ever exist

Nematoda

Roundworms - extremely common, relatively simple

Causing variety of parasitic diseases

Body plan: Soft body, through gut, simple PSEUDOCOELOM, PIERCING MOUTHPARTS

Arthropods

Tardigrades, vervet worms, true arthropods

1. Exoskeleton (movement)

2. Moulting (Shed exoskeleton to continue to grow)

3. Limb segmentation (Sacrificed flexibility for power)

4. Body segmentation (gathering related segments into tagmata)

5. Open circulation (blood mixes with other bodily fluids -> hemolymph. the cavity it sloshes in is the homecoel)

Vision: very simple to very complex

- pit eyes (light, direction)

-compound eyes - detailed images

Chelicerata

2 tagmata (prosoma - movement, feeding. Opisthosoma - life support, reproduction

Spiders, scorpions, horshoe crabs, others

Piercing mouthparts - may be hollow to inject venom, digestive enzymes

Very limited ability to chew food

Pedipalps: limbs near mouth for feeding, sensation defense, or mating

Mandibulata

myriapods (centipedes, millipedes), pancrustacea (crustaceans, insects)

Mandibles: pair of mouthparts that open, close like scissors

Myriapods

centipedes and millipedes

Start short, add a segment after every moult

Centipedes: fast moving predators

-legs splayed out to sides

- front pair of legs modified into venom injecting structures called toxinognaths

Millipedes: herbivores, legs underneath, slower

Pancrustacea

3 tagmata (head, thorax, abdomen)

Malacostraca (sterotypical crustaceans)

- colonized land on multiple occasions, but largely aquatic

Parasites

- branciura - tongue eating isopods

Filter feeders

- barnacles

Insects

Insects

Most successful group of animals to ever exist

3 tagmata of all crustaceans (head, thorax, abdomen)

Mandibles

6 legs

Air breathing

Wings

First animals to fly

Respiration: Tracheal system

- air enters through holes in skin (spiracles)

- travels through tiny tubes in body

- every cell gets own air supply

- not efficient - limits max body size

Paleoptera

Lacking ability to flex wings over back at rest

Dragonflies, relatives

Holometabola

Born- tiny, wingless version of adult

Get bigger w/ each moult, growing wings in final stage (imago)

Eumetabola

Start live at worm-like larva

Undergo metamorphosis, during which it encloses itself in a pupa

successful because of niche partitioning