Echinoderms and Arthropods Review

What does the word echinoderm mean?

Spiny skin.

What does it mean to be benthic?

To be bottom dwelling.

Why are echinoderms only found in marine environments?

Because they are unable to osmoregulate.

During development, the blastopore of an echinoderm develops into what structure? What do we call these animals as a result?

Develops into an anus, we call them deuterostomes.

Give three words or phrases to describe the symmetry of an adult echinoderm.

Circle, uneven, odd.

What is the advantage of ts type of symmetry found in the adults?

Allows them to be able to sense predators from all directions.

What type of symmetry do echinoderm larvae have?

Bilateral symmetry.

What do we call the two surfaces of an echinoderm? How can you recognize each?

Oral, and aboral, the oral side has the mouth.

Echinoderms have what type of skeleton?

Endoskeleton.

What do we call the plates that make up the skeleton of echinoderms? How are they different from bones?

Ossicles, different because they project upward through the skin.

Tiny pincer-like appendages surrounding the spines are called what? What are they used for?

Pedicellariae, used for protection, and cleaning.

What three structures do echinoderms have in place of a brain?

Central nerve, nerve ring, and nerve Net.

What structures allow echinoderms to see light? Where are these structures located?

Eyespots, located at the end of each arm.

What are the four functions of the water-vascular system?

Locomotion, food gathering, respiration, and excretion.

Describe the water-vascular system.

A fluid-filled system, made up of interconnected canals, thousands of feet that function due to water pressure.

Through what structure does the water enter and leave the water-vascular system?

Madreporite.

Once water enters the water-vascular system, describe the path it takes to reach the tube feet.

Water travels into the stone canal, ring canal around the mouth, Tied Mann’s bodies, and finally Radial canals.

What is the function of Tiedemann’s bodies?

Capture, rupture any bacterial cells that made it that far.

Where are the tube feet located on a sea star?

How is gas exchange and waste excretion accomplished without excretory or respiratory systems?

Through diffusion.

List the major organs of the digestive system of a sea star.

Pyloric caeca, intestine, and the anus.

Describe how most echinoderms reproduce.

Free spawning, eggs and sperm are released into the water.

What is a Bipinnaria?

Fertilized eggs, that develop into a bilateral free swimming larva.

What does the word Echinoidea mean?

Spine-like.

List the four types of echinoids.

Sea urchins, sea biscuits, sand dollars, and heart urchins.

The fused, rigid endoskeleton of an echinoid is called what?

A test.

If you break open a test, what will you find inside?

Many hard, white loose teeth everywhere.

The complex jaw-like mechanism of an echinoid is called what?

Aristotle’s Lantern.

What is the name of the most venomous sea urchin? Where are they found? What allows it to sting?

Flower Urchin, Indo-West Pacific, the pedicellariae.

Why is it dangerous to step on a long-spined sea urchin?

They can break off inside you.

How are Diadema Sea Urchins ecologically beneficial?

It feeds on algal turf, without it the turf could destroy coral reefs.

What does Holothuroidea mean?

Water Polyp.

What do sea cucumbers do when they are threatened? What is it called?

They expel most of their internal organs to confuse predators, eviscerato

The numerous white strings expelled by a sea cucumber are called what? What danger do they pose to humans?

Cuvierian tubules, it can cause blindness.

List two main types of echinoderms in class Ophiuroidea.

Brittle stars, and basket stars.

What does Ophiuroidea mean?

Snake tail.

Where can we find brittle stars?

Little or no light areas with hard surfaces.

List two main types of echinoderms in Crinoidea. How are they different from other echinoderms?

Sea lilies, and feather stars, they are both sessile, but feather stars can detach and become free swimming.

What does Crinoidea mean?

Lily-like.

Outbreaks of what venomous sea star pose one of the most significant threats to the Great Barrier Reef?

Crown-of-thorns-sea star.

One of the largest and fastest sea stars in the world is found in the northeast Pacific from Alaska to Southern California. What is it called?

Sunflower Seastar.

What is different about how a sunflower star eats?

Is able to open its mouth really wide, and make its body bigger to take in its prey.

What sea star is common in the marine aquarium trade and named after a popular desert?

Chocolate Chip sea star.

What benefit are sand dollars and see cucumbers to a deep ocean ecosystem?

They burrow in the sand which provides more oxygen at deeper depths.

How do farmers use echinoderms?

The skeleton is used as a source of lime where limestone is unavailable.

Sea urchins have long been a model organism for what branch of science?

Embryology

How do sea otters help kelp forests? Why is this important?

Otters eat sea urchins, which helps keep the balance of the sea urchins not destroying forests of kelp.

Pentameral

The body plan where the adult form exhibits five-fold radial symmetry, with the body divisible into five similar regions around a central axis, despite their larval stage being bilaterally symmetrical.

Papulae

Small, ciliated projections of the body wall that serve in respiration and waste removal, facilitating gas exchange and excretion through diffusion across their surfaces. 

The word arthropod means what?

Jointed Foot.

What do we call the external body parts that protrude from an organism’s body, such as legs, mouthparts, and antennae?

Appendages.

What is the advantage of jointed appendages?

More flexible, specialized for functions.

The specialization of regions of the body for specific functions is called what?

Tagmatization.

Arthropod exoskeletons are made primarily of what carbohydrate polysaccharide?

Chitin.

What are the main functions of the exoskeleton?

Protection, attachment for muscles, locomotion, and prevention of water loss.

Name the two layers that make up the exoskeleton.

Epicuticle (outside layer), and the procuticle (inside layer).

Arthropods must shed their exoskeleton periodically, what are the two names for this process?

Molting and ecdysis.

Explain the molting process.

Enzymes are secreted from the outer layer, enzymes digest the old procuticle and separate the exoskeleton fro the rest of the body inside.

How is insect molting different from that of spiders and some crustaceans?

Spiders and crustaceans can sometimes molt an indefinite amount.

Name the three major body segments of insects.

Head, thorax, and abdomen.

What segment is formed when the head fuses with the thorax?

Cephalothorax.

What are the two main types of feeding appendages in arthropods?

Chelicerae and mandible jaws.

How are ocelli different from compound eyes?

Ocelli are way less complex, and can only sense light and dark.

For each of the three major groups of arthropods, list their respiratory organs.

Crustaceans: Gills

Spiders: Book Lungs

Terrestrial insects: Trachea, spiracles.

Describe the circulatory system of arthropods.

Open circulatory system heart at the top of body, squeezes blood out of internal body spaces.

Arachnids and insects use what organ for excretion? Besides getting rid of wastes, what else does this organ do?

Malpighian tubules, also used to conserve water.

How do crustaceans regulate their salt balance?

They use their antennal glands.

What are the 4 different stages of complete metamorphosis?

Egg, Larva, Pupa, Adult.

What percentage of insects go through complete metamorphosis? Why is this number so high?

90%, larval stage it eats different foods, and lives in different environments from adults reducing competition for food.

What are the 3 different stages of incomplete metamorphosis?

Egg, Nymph, Adult.

What organisms are in Subphylum Chelicerata?

Horseshoe crab, spiders, ticks, mites, and scorpions.

What organisms are in Subphylum Crustacea?

Lobsters, crabs, crawfish, shrimp, copepods, barnacles, sand fleas, and pill bugs.

What organisms are in Subphylum Hexapoda?

Insects, (ants, bees butterflies, etc.)

What organisms are in Subphylum class Myriapoda?

Centipedes, and Millipedes.

Name the six pairs of cephalothoracic appendages on chelicerates.

Chelicerae, pedipalps, walking legs.

What structures help arachnids to be predators?

Fangs, claws, and venom glands.

What do arachnids have to do before they can eat their food?

Release a digestive enzyme that liquefies the tissues of the prey.

List the ways in which spiders can capture their prey.

Chase down and inject with poison.

Make webs to catch and tangle prey.

Make trapdoors to catch prey.

How is a spider web produced?

They produce the silk with silk glands and it comes out through the spinnerette.

What are the 2 most dangerously venomous spiders to people and where do they live?

Brazilian Wandering Spider (Central and South America) and the Sydney Funnel webs Spider from Australia.

What are the 2 types of spiders in the United States that can give severe or even fatal bites?

Black Widow, and the Brown Recluse.

How are harvestmen different from spiders?

Only have one main body section, can’t build webs, lack venom, omnivores, only two eyes.

What unique feature differentiates mites and ticks from other arachnids?

The head, thorax, and abdomen are all fused.

What parasitic mite burrows and lays eggs inside the skin causing relentless itching and an angry rash?

Sarcoptes Scabiei.

Name the world’s top two disease vectors.

Mosquitoes and Ticks

What tow diseases can be carried by ticks? What types of ticks carry these diseases?

Lyme disease (deer ticks) , and Rocky Mountain Spotted Fever. (dog and wood ticks)

What arthropod is called a ‘living fossil’?

Horseshoe Crabs.

What groups of arthropods have been nicknamed “insects of the sea?”

Subphylum Crustacea.

Compare and contrast crustaceans to terrestrial arthropods?

Insects: Six legs.

Both: Exoskeleton, jointed appendages, head thorax, and abdomen,

Crustaceans: two pairs of antennae.

What do we call large marine crustaceans with five pairs of walking legs?

Decapods.

What species has the largest leg span of any arthropod?

The Japanese Spider Crab.

What rainbow-colored species has two club-shaped appendages that it punches out to break the shells of mollusks.

The Peacock Mantis Shrimp.

What two species of crustaceans live on land?

Pill bugs, and sand hoppers.

What does the class name Hexapoda refer to?

The presence of six legs.

Describe the types and locations of appendages on insects.

Jaws, 1 pair of antennae, 3 pairs of jointed legs on thorax, some with 1 or 2 pairs of wings.

The study of insects is called what?

Entomology.

List reasons why insects are so successful.

Ability to fly, sturdy exoskeleton, shorter lifespan, communication.

A chemical released by one organism that affects the behavior of other organisms of the same species through smell or taste is called what?

Pheromones.

List and describe the three types of color defense of insects.

Mimicry: imitation of a noxious species (having a bad taste, odor, or poisonous properties).

Aposematic: coloration is a warning coloration to advertise noxious qualities.

Camouflage: it is what it is.

What does it mean for an insect to be social?

To work together as a colony.