BIOL 2 Test 4

Phylum Mollusca

Squid, Snails, Slugs

* Soft bodied animals
* Produce a valve (shell) usually
* Have cephalization
* Bilateral symmetry, coelomate, no segmentation

Structural Characteristics of Phylum Mollusca

* Head-Foot Region
* Visceral Hump
* Mantle

Head-Foot Region

* Small brain (octopus and squid are exception)
* Foot is a muscular structure, mostly involved in locomotion

Visceral Hump

* Contains most important organs
* Usually covered by shell

Mantle

* Thin layer of tissue
* Produces the valve (or shell)
* Protects the body from debris
* Could produce pearls

Phylum Mollusca Classes

* Class Bivalvia
* Class Gastropoda
* Class Cephalopoda

Class Bivalvia

* 2 shells (valves) that fit together with no opening
* Lack cephalization
* Filter feeders
* Sessile
* All are edible

Class Gastropoda

Snails and Slugs

Snails

* One valve with one opening
* Mostly herbivores but some are predators
* Cone shell are predators
* Can be left handed or right handed
* Torsion

Torsion

Developmental change that brings the anus to the front

Slugs

* Modified valve, no openings
* Top of the body, behind the head, and inside the mantle
* Terrestrial or marine
* Mostly herbivores

Class Cephalopoda

Head-Foot Animals

Octopus, Squid, Nautilus

Class Cephalopoda Characteristics

* Have a well developed brain
* Remember a little, can problem solve
* Well developed eye
* Ink glands
* Chromatophores
* Closed circulatory system
* Blood is contained within vessels

Chromatophores

Pigmented cells

Change color or tone

Squid

* Move very fast
* Scavengers
* Use modified foot and mantle into a siphon (force water through)
* Economically important
* Valve called a pen

Nautilus

* Very fast
* Predators
* Chamber outer shell (full of air)

Octopus

* Crawl using arms
* Jet propulsion only when threatened
* Predators
* No shell

Umbo

Oldest part of a shell

Phylum Annelida

* Segmented worms
* Coelomate, cephalization, bilateral, segmented
* Earthworms, Leeches, Polychaetas

Phylum Annelida Segmentation

* Body is divided into somites
* In each somite are major organ system
* Nephridia
* Closed circulatory system

Nephridia

Excretory organs in each somite

Closed Circulatory System

2 main vessels and aortic arches (hearts)

Phylum Annelida Classification Characteristics

Setae

Clittelum

Parapodia

Setae

* Hair-like projections, not appendages
* Usually involved in movement or anchoring the body to burrow

Clitellum

* Secretes mucous
* Involved in reproduction

Parapodia

* Appendages
* Involved in movement (locomotion)

Phylum Annelida Classes

Class Oligochaeta

Class Hirudimea

Class Polychaeta

Class Oligochaeta

Earthworms

* Short setae, clitellum starting at maturity, no parapodia
* All terrestrial
* Major decomposers
* Oxygenate the soil

Decomposers

Breakdown dead organic decaying matter in soil

Digestive Tract of Class Oligochaeta

Mouth → Pharynx → Esophagus → Crop → Gizzard → Intestines → anus

Pharynx

Muscular structure

Crop

Storage organ

Gizzard

Grinding organ

Class Oligochaeta Reproduction

* Monecious
* Each worm has testes and ovaries, make sperm and egg at same time
* Seminal Vesicles
* Seminal Receptacles
* Copulation

Seminal Vesicles

Holds the worms sperm

Seminal Receptacles

Holds the sperm from the other worm

Copulation

* Side by side with another worm, mucous dries out, the worms are stuck together so they can exchange sperm
* Worms pull apart and mucous clumps on each worm to form a cocoon
* Each worm secretes their eggs and other worms sperm into cocoon
* Fertilization takes place in cocoon (external fertilization)

Class Hirodimea

Leeches

* Mostly ectoparasites or predators
* Blood Meal
* Not usually a vector for disease
* Medicinal leeches
* Secrete an anticoagulant to keep blood from clotting

Class Polychaeta

Polychaetas

* Nereis
* Sea mouse
* Tubeworms
* All filter feeders

Nereis

Clamworm

Tubeworm

* Live in a burrow
* Burrow into sediment
* Bore a hole in a rock
* Make their own tube

Phylum Echinodermata

* Acoelomate, no cephalization, no segmentation
* Pentaradial Symmetry
* Lack most systems that other creatures have

Pentaradial Symmetry

* 5 ways can be divided
* Unique feature
* Variation of radial symmetry

What Phylum Echinodermata Have

* Have a digestive system
* Have simple reproductive system
* Have water vascular system

Oral Side of Starfish

Side mouth is on (bottom)

Aboral Side of Starfish

Opposite of the oral side

Spine

Dots on starfish aboral side

Madreporite

Opening to water vascular system

Osmoregulation

* Adjustment to salinity changes
* Echinoderms cannot do this

Phylum Echinodermata Classes

Class Asteroidea

Class Ophiuroidea

Class Echinoidia

Class Holothuroidea

Class Asteroidea

Starfish

* All predators (or scavengers)
* Move using tube feet

Class Ophiuroidea

Brittle Stars

* Scavengers (or predators)
* No tube feet
* Arms free to move, crawl
* Negatively phototropic

Class Echinoidia

Sanddollar

Sea Urchin

Sanddollar

* Shallow water
* Predators
* Plates fused, no arms
* No tube feet
* Move by spines

Sea Urchins

* All herbivores
* Fused plates, arms not free
* Have tube feet, move using combination of spine and long tube feet

Class Holothuroidea

Sea Cucumbers

* Soft, no hard parts
* Not colorful
* Have tube feet for movement and attachment
* Have tenacles
* Filter feeders
* Eviscerate

Eviscerate

Turn inside out and release their organs. Can regenerate the organs

Regenerate

Almost all Echinoderms can ______

Test

Endoskeleton of plates

Phylum Arthropoda

* Most advanced invertebrates
* Coelomate, cephalization, bilateral, segmented
* Accounts for 2/3 of all animal species

Tagma

In Phylum Arthropoda, somites are fused into larger segments

Phylum Arthropoda Behavior

* Complex
* Mostly innate (genetic)
* Hormones (phenomes)

Phylum Arthropoda Exoskeleton

* Made out of chitin
* Outside skeleton (shell)
* Protection
* Something for muscles to push and create complex movement
* Appendages are jointed to allow complex movement

Ecdysis

* Arthropod prepares to shed exoskeleton
* Molting (sheds exoskeleton)
* Makes a new exoskeleton

Appendages

There are more types of ______ in Phylum Arthropod than any other phylum

Metamorphosis

Body structure (design) changes with age

Complete Metamorphosis

Egg → Larvae → Pupa → Adult

EX: Moth, Fly, Beetle

Maggot

Fly larvae is called a ______

Grub

Beetle larvae is called a ______

Incomplete Metamorphosis

Egg → Nymph (stages) → Adult

EX: Grasshopper

Adult Polymorphism

* More than one body type or an adult
* Social insects
* EX: Honeybee

Queen Honeybee

Sexually mature female

Worker Honeybee

Sexually immature female

Drone Honeybee

Sexually mature male, breed with the queen

Subphylum Myriapoda

* 2 types
* Head and trunk
* Seem wormlike
* Centipede
* Millipede

Centipede

* 100 legged worm
* 1 pair legs per segment
* Very fast
* Venomous

Millipede

* Million-legged worm
* 2 pair legs per segment
* Slow
* Herbivore
* Harmless

Subphylum Hexapoda

* Largest class of animals
* Have 3 tagma
* Head, thorax, abdomen
* 2 pairs of wings

Subphylum Crustacea

Have branching appendages

EX: Acorn barnacles, Pillbugs/Rolypoly/Sowbugs, Decapods

Acorn Barnacles

* Shelled arthropods


* Sessile (attach to hard surface)


* Damage man-made objects (fouling)

Pillbugs/Rolypoly/Sowbugs

Harmless, terrestrial

Decapods

Crayfish, Lobster, Shrimp, Crabs

* 5 pairs of walking legs
* Economically important as food
* 1st pair legs modified as pinchers

Subphylum Chelicerata

* Lack mandibles (lower jaws)
* All have an appendage called a chelicerae
* 2 examples
* Horseshoe crab
* Class Arachnida

Chelicerae

Sucking appendage, could be attached to fangs

Horseshoe Crab

Not a true crab

Class Arachnida

* Mostly like warm climates
* EX: Ticks, Fleas, Chiggers, Harvestmen, Scorpions, Spiders

Tick

* Ectoparasite
* Lyme disease
* Rocky Mt. Spotted Fever

Scorpion

Predators

Venomous

Spiders

* Cephalothorax and Abdomen (2 tagma)
* Predators (bite their prey)
* 2 Venomous Types
* Black Widow
* Brown Recluse

Black Widow

* Female is venomous
* Neurotoxic
* Painful but not fatal

Brown Recluse

* Hemotoxin (kills tissue)
* Could be fatal

Phylum Cordata

* Includes all vertebrates
* Backbone of bone and cartilage

4 Hallmarks of Chordates

1. Postanal Tail
2. Dorsal Nerve Cord
3. Notocord
4. Pharyngeal Gill Slits

Postanal Tail

Some chordates the tail disappears (humans)

Dorsal Nerve Cord

Connects the brain to the rest of the nervous system

Notocord

* Embryonic “backbone”
* Axis of the body
* Eventually protect the nerve cord

Pharyngeal Gill Slits

Slits in the side of head where gills will eventually form in aquatic vertebrates

Subphylum Vertebrata

* Backbone as an adult of bone or cartilage


* Cranium

Cranium

Thicker endoskeleton around the brain for protection