Part 1.

Phylum: Arthropoda/ Subphylum Mandibulata  

Class: Crustacea

Cray Fish


Above photo is an internal dissection of a crayfish

External Anatomy:


Internal Anatomy:


Difference between male and female: In the males, there are two tiny protuberances that look like extra legs. Females do not have these.

Gills and Mechanisms of Gas Exchange: Oxygen goes in the blood, which is called hemolymph in a crayfish, and carbon dioxide goes out. Efficient breathing , one needs to maximize the surface area where the gas exchange occurs.


IMG_5995 2


External Anatomy:


Gills and Mechanisms of Gas Exchange: The gills of the shrimp are located on the outer branches of the pleopods. They have as large of a surface area as possible so that enough oxygen goes through when water passes over it. The oxygen diffuses through a thin membrane and enters into the bloodstream of the shrimp. They also use a respiratory pigment called hemocyanin, which is a copper-based that helps transport oxygen throughout the body

Sensory System: A compound eye made up of optical units called ommatidia. Each eye is divided horizontally in three regions, the dorsal hemisphere, the mid-band and the ventral hemisphere which all explore the space. Shrimp that live in deeper waters have their filters shifted to transmit shorter wavelengths (green-blue light) as longer wavelengths are attenuated by the water. This makes them able to distinguish smaller differences of the short wavelength light in the ocean. The nerves branching from the nerve cord help the shrimp gather information from its sensory organs. A shrimp’s sensory organs are numerous: olfactory receptors to help it detect pheromones, fibers lining its legs to let it assess its environment through touch, even a sensory dorsal organ that somehow complements other organs’ actions.



IMG_5993 2.jpg


Above Photo: A flat worm attached to a crab shell

External Anatomy:


Gills and Mechanisms of Gas Exchange: The gills on the outside of their body have the ability to extract oxygen from the water. The crab uses the counter current flow to allow the maximum amount of oxygen in their body and release the maximum amount of deoxidized water through the capillaries that are found inside of the gills.

Sensory System: Crabs have sense organs such as Setae, sensory hairs found on the exoskeleton and antennae, two pairs of sensory organs used to gather information regarding a hermit crabs surroundings. Antenna – the longer outer pair often referred to as “feelers” used to touch and feel what is in the crabs path. Antennule – the inner “bent” pair which enable the crab to taste and smell (this is the pair that you touch gently with food when beginning to hand feed your crab with The Hermit Crab Patch Feeder Spoon).

Horseshoe Crab



Gills and Mechanisms of Gas Exchange:
Gas exchange in horseshoe crabs happens between the blood and the sea water through their book gills. They absorb oxygen from the water.

Sensory System: Compound eyes made up of units of 8 to 14 retinular cells grouped around a rhabdome. They are able to detect movement, but there are too few ommatidia in their eyes for image formation Male crabs use their eyes to locate females. Females use their eyes to avoid other nesting females

Similarities between marine crustaceans:

  • They have soft bodies with an exoskelton
  • They are aquatic
  • Shrimp and crayfish have uropods and telson
  • Crayfish, crabs, and shrimp all have antennae, carapace, and a mouth
  • Crayfish, crabs, and shrimp all have a form of an eye and legs

Differences between marine crustaceans:

  • Shrimps have abdominal segments
  • Crayfish live in freshwater
  • Shrimp have lamellar gills
  • Crayfish have antennules and maxillipeds

Daphnia Internal/External Structure



Live Barnacles looked at during class


External Anatomy:


Feeding Behavior of Barnacles: Based on factors such as water flow direction, flow velocity, type and location of substratum, predators, systematics, and more. Different feeding behaviors can be a result on the abundance of food in that particular region. They have long thin feeding limbs in habitats with little wave action and thick feeding limbs in wave exposed habitats. They can be suspension feeders and capture plankton and smaller food particles. The water velocity effects the feeding limbs, which effects how much food is collected.

Decapod Anntenal Gland: The anntenal gland rests in the basal

antennal segment of the cephalothoraxIt is composed of four macroscopic substructures arranged in series. In a way, it is like a single giant nephron:a coelomosac, derived from the vestigial coelom of the animal, and intimately associated with the gland labyrinth, filters. Hemolymph delivered by the antennal artery.

Nauplius Larvae Slide:
Shrimp: Some species of shrimp have several mating partners over the course of their lives. Reproduce through sexual reproduction.
Crabs: Sexual reproduction. Male and female need to mate to fertilize the eggs. During mating, the male crab carries the female on his back for up to two weeks, after which the female stores the male’s sperm in sacs on her abdomen. Females then lay their eggs.

Lobsters: Females Lobsters mate during the soft-shell phase after molting. Before molting, the female approaches a male and releases her scent in a stream of urine. The two spar briefly, then the female places her claws on his head to let him know she is ready to molt and mate.


Part 2.

Class: Myriapoda

Myriapods (Preserved)

Diplopoda- Millipedes


Features: “Double-foot”. Elongated, segmented bodies with two leg pairs per segment. Short antennae. Compact body, making it easier to plow through soil. Spiracels to help them breathe. Their primary food source isDecaying organic material. They cope with threats by curling into a ball and secreting toxic or unpalatable substances through their exoskeletons

Chilopoda- Centipedes

Features-  Typically around 2 inches long. Same segmented body as millipedes, with a rounded head capped by two long antennae. One pair of legs per body segment. The last pair of legs is also specialized and is longer than the rest, allowing the centipede to catch and hold its prey while it injects venom. The centipede’s legs stick out from its body on both sides, making it easy to distinguish from the millipede, which has all its legs underneath it.

Commons Names of Insect Order

  •   Odonata- Dragonflies and Damselflies
  •  Isopter- Termites
  •  Orthoptera- Grasshoppers, Crickets, and Locusts
  • Hemiptera- True Bugs, Cicadas, Leafhoppers
  • Coleoptera- Beetles and Weevils
  •  Diptera- Flies and Mosquitoes
  •  Siphonaptera- Flea
  •  Lepidoptera- Butterflies and Moths
  • Hymenoptera-  Wasps, Bees, Ants

Preserved Insects

Odonata- Dragonflies and Damselflies


Dragonfly Nymph/ Image Mag: 4x

 Dragonfly Wing Tip/ Image Mag 4x


Orthoptera- Grasshoppers, Crickets, and Locusts


External Anatomy:

IMG_6382 2

Internal Anatomy:



Hemiptera- True Bugs, Cicadas, Leafhoppers

Coleoptera- Beetles and Weevils


Mouthparts- Mandibulate mouthparts designed for biting and chewing

Feeding- Herbivores, scavengers or predators, and some adult beetles do not feed at all

Digestion- The digestive system consists of alimentary canal (gut) and salivary glands, and is responsible for all steps in food processing: digestion, absorption, and feces delivery and elimination

Diptera- Flies and Mosquitoes

Mosquito/ Image Mag: 4x


Mouthparts- Distal end of the head. Mouth is modified and combined into a sucking proboscis. Some species have non-functional adult mouthparts

Feeding- Feed on plant or animal juices or other insects. Some are bloodsuckers.

Digestion- The digestive system consists of alimentary canal (gut) and salivary glands, and is responsible for all steps in food processing: digestion, absorption, and feces delivery and elimination

Siphonaptera- Flea


Lepidoptera- Butterflies and Moths


Mouthparts- Jaws only present in the caterpillar stage mainly consist of the sucking kind reduced mouthparts and therefore do not feed in the adult state maxillary galeae and is adapted for sucking nectar. The shape and dimensions of the proboscis have evolved to give different species a wider and therefore more advantageous diet. Two feeding guilds.

Feeding-  Each tube of the feeding guilds are inwardly concave, thus forming a central tube up which moisture is sucked. Suction is effected through the contraction and expansion of a sac in the head. The species nectarivorous obtain the majority of their nutritional requirements from floral nectar and those of the frugivorous guild who feed primarily on juices of rotting fruit or fermenting tree sap. Certain noctuid species have developed piercing mouthparts; the proboscis has sclerotised scales on the tip with which to pierce and suck blood or fruit juices.

Digestion- The digestive system consists of alimentary canal (gut) and salivary glands, and is responsible for all steps in food processing: digestion, absorption, and feces delivery and elimination

Hymenoptera-  Wasps, Bees, Ants


Open Circulatory System in Insects

“Blood” is confined to vessels during only a portion of its circuit through the body. The remainder of its journey takes place within the body cavity (called the hemocoel). For this reason, insect “blood” is called hemolymph

Trachael System in Insects

Exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. Tracheae open to the outside through small holes called spiracles. Spiracles open into large tracheal tubes. These, in turn, lead to ever-finer branches. The branches penetrate to every part of the body

Major Features of Hexapod Malpighian Tubules

Any of the excretory organs that lie in the abdominal body cavity and empty into the junction between mid-gut and hind-gut. In species having few malpighian tubules, they are long and coiled. In species with numerous (up to 150) tubules, they are short.

Holometabolous and Hemimetabolous Development in Insects

Holometabolous- A complete metamorphism, four life stages – as an embryo or egg, a larva, a pupa and an imago or adultsynapomorphic trait of all insects in the super order Endopterygota

Hemimetabolous– Incomplete metamorphosis and paurometabolism. It is the mode of development of certain insects that includes three distinct stages: the egg, nymph, and the adult stage, or imago. These groups go through gradual changes; there is no pupal stage. The nymph often somewhat resembles the adult stage but lacks wings and functional reproductive organs.

Part 3.

Subphylum: Chelicerata

Common Names of Insect Order:

  •  Merostomat- Sea Scorpions, Horseshoe Crabs
  • Arachnida- Spiders
  • Acari- Mites, Ticks
  • Araneae- Spiders
  •  Scorpiones- Scorpions
  • Amblypgi- Whip spiders, tailless whip scorpions

Horseshoe Crab


Acari- Mites, Ticks

Ixodes Dammini Female/ Image Mag: 4x


Ixodes Dammini Male/ Image Mag: 4x


Deer Tick Nymph/ Image Mag: 4x                     Deer Tick Adult/ Image Mag: 4x


Mite Anatomy                                                  Tick Anatomy


Preserves Spider

Hunting Spider                                 Unknown:                      Black Widow

External Anatomy:


Hairs, Bristles, and Trichobothria used for Mechanoreception:

The bristles respond to touch and trichobothria responds to air currents and sound. Air current receptors are involved in alarm behavior (filiform hairs on the cerci of crickets and cockroaches) as well as prey detection (trichoboth-ria of spiders); touch receptors (bristles) report direct mechanical contact, but are also involved in regulation of body position (hair plates in the neck region of bees.

External Anatomy of Scorpion


External Anatomy of Amblypigid


Respiratory Structures


There are at least five different respiratory systems in spiders, depending on taxonomic group
and whom you’re talking to.
1) A single pair of booklungs, as with the cellar or daddy-long-leg spiders, Pholcidae.
2) Two pair of booklungs, suborder Mesothelae, and all or most of infraorder Mygalomorphae
(including tarantulas).
3) A pair of booklungs and a pair of tubular trachea, as in the orbweavers and wolf spiders, and
probably most species of spiders.
4) A pair of tubular trachea and a pair of sieve trachea (or two pair of tubular trachea if you’re
one of those who doesn’t believe the difference between tubular and sieve trachea is enough to
distinguish them from each other), as in the small spider family, Caponiidae.
5) One pair of sieve trachea only, as in the small spider family Symphytognathidae.
Book Gills are covered in a membrane that allows oxygen to enter, but repels water. The first of the six pairs is called the operculum. The operculum covers and protects the other five pairs of gills.
Terrestrial Adaptions
Spin sticky webs which they use to capture insects. Their venom paralyzes the prey. Spider venom also works as a digestive enzyme, which dissolves the insides of the prey, allowing spiders to drink the nutrients. They have locomotive adaptations, their eight legs made up of seven segments each, spiders can move quickly and adeptly. Some spiders also have camouflage colors as an adaptions.
Horseshoe crab’s vision is an adaptation and they have 7 eyes on top of their bodies. The final light sensing organ is located along the length of their tail, scientists think that they help the arthropods to synchronize their activity pattern with the lunar cycle. Their carapace used for protection of their soft bodies. Horseshoe crab legs help bring food into their mouth. They also have a primitive immune response that detects endotoxins.

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