Exam III STUDY GUIDE BIO

What characteristics is common to all organisms in the phylum Nematoda?

All possess a nonliving secreted cuticle.

What is ecdysis?

Process of molting the cuticle

What are the three layers of the cuticle?

Cortex, matrix layer, basal layer

What are the two primary structures that function in chemoreception and where are they located?

Carotid bodies and Aortic bodies located in the neck and chest.

Why are all nematodes round?

Because the body contains muscles contracting against the pseudocoelomic fluid and generating an equal outward force

What type of digestive system do nematodes possess?

A complete digestive system

What are Renettes and what system do they function in?

A granular system in aquatic species and consist of ventral gland cells posterior to pharynx. Each gland absorbs waste form pseudocoelom and empties them through an excretory poor.

What is the difference in aquatic versus parasitic nematode excretory systems?

Aquatic species has granular system while parasitic nematodes have a tubular excretory system.

What is dimorphism and how does it appear in nematodes?

It happens when males are smaller than females. Gonads are long and cold and live freely in pseudocoelom, and the female system has pair of convoluted ovaries.

What purpose do the spicules serve in reproduction?

They extend from the cloaca and inserted into female genital pore to aid in copulation

List and explain the adaptations that parasites have.

High reproductive potential, lifecycles that increase likelihood of transmission from one host to another, enzyme resistant cuticle and eggs, Encysted larvae.

Ascaris lumbricoides?

Giant intestinal roundworm of humans, live in small intestines of humans, produce large numbers of eggs that exit with feces.

Enterobius vermicularis?

Human pinworm, most common roundworm parasite in the United States, established in lower region of large intestine, at night gravid females migrate out of the rectum to perianal area.

Trichinella spiralis?

Pork worm, live in Mucosa and small intestine of humans and other carnivores/omnivores, humans are infected by consuming improperly, cooked pork products.

Wuchereria bancrofti?

Filarial worms, prominent in tropical countries, elongate, thread, like nematodes that live in lymphatic systems.

What are the functions of the exoskeleton?

Provides structural support, protection, Impermeable surfaces for the prevention of water loss, and systems of levers for muscle attachment and movement.

What are the two layers of the exoskeleton and what do they do?

Epicuticle- Impermeable to water and serves as a barrier to microorganisms and pesticides. Procuticle- composed of chitin and acts as a barrier against water loss and foreign matter.

What are the four primary stages of ecdysis

1. Enzymes begin digesting old pro cuticle and separate the hypodermis and exoskeleton.

2. New procuticle and epicuticle are secreted.

3. Old exoskeleton split open along predetermined ecdysial lines (when animal stretches during air or water intake).

4. Calcium carbonate deposits and/or sclerotization harden the new exoskeleton.

What are the prosoma and the opisthosoma and what do they contain?

Prosoma (cephalothorax)- sensory, feeding, and locomotor tagma (usually bears eyes).

Opisthosoma - contains digestive, reproductive, excretory, and respiratory organs.

What are chelicerae and pedipalps?

Chelicerae- Pincerlike or chelate, often used in feeding, may be specialized as hollow fangs.

Pedipalps- Usually sensory, may be used in feeding, locomotion, or reproduction.

What are coxal glands and Malpighian tubules?

Coxal Glands- sacs that are bathed in blood of body sinuses, nitrogenous wastes enter sac then to excretory pores.

Malpighian Tubules- Absorb waste materials from blood and empty to gut tract.

What type of lungs do arachnids posses?

Some posses book lungs (air enters body and moves over series of lamella that look like book pages)S

Describe the stinging region of scorpions?

Sting region has a bulbul base that contains venom-producing glands, Hollow, sharp, barbed point, and smooth muscles that eject venom during stinging.

Describe the functions and the structure of spider silk?

Chemical structure is different. among species but usually a repeating sequence of glycine and alanine. Amino acids assemble into beta sheets that form crystalline structure. It functions include: prey capture, web construction, and offspring protection.

What is the medicinal relevance of mites and ticks?

Mites causes local inflammation and intense itching at site of bite. Ticks significantly cause many human diseases.

What are the two main differences in crustaceans and arthropods?

Crustaceans haver two pairs of antennae and posses biramous appendages.

The general functions of crayfish appendages are what?

They function as sensing, feeding, locomotion, and reproduction. 1st+2nd pair are for sensing, 3rd+4th+5th are for feeding, 6th-8th are also for sensory and food-handeling, 9th-13th are for locomotion, while the last pair are for reproduction.

How does gas exchange occur in crayfish?

Gills attach to bases of some appendages and are present in gill chamber, Water is driven through gills → oxygen and carbon dioxide are exchanged, Respiratory pigment (hemocyanin carries oxygen in blood plasma).

What are statocysts and why are they important?

They provide information regarding movement, orientation, and vibrations.

What features of crayfish are controlled by the endocrine system?

Ecdysis, sex determination, and color change.

Why are androgenic glands important in crayfish?

They promote development of testes and male characteristics (monopods- male reproductive structures).

What is the function of antennal or green glands?

Excretory products form by filtration of blood and dilute urine is made then excreted.

How do organisms in the group insecta facilitate gas exchange?

Spiracles are present in the abdomen which serves as gas exchange. Also goes through the highly branched system of respiratory surfaces called tracheae.

Describe synchronous and asynchronous flight and provide examples of insects that use each?

Synchronous is called Direct flight (muscles act directly on bases of wings to contract and produce downward thrust) (Ex: Butterflies, Dragonflies, Grasshoppers)

Asynchronous is called Indirect flight (Muscles change the shape of the exoskeleton for both upward and downward wing strokes) (Ex: Flies and Wasps)

What are the three main regions of insect digestive tracks and what are their functions?

Foregut, Midgut, and Hindgut

Foregut function?

Modified into a muscular pharynx

Midgut function?

Provides the surfaces for digestion and absorption

Hindgut function?

Primary involved with the reabsorption of water.

How do insects regulate their body temperature?

They are considered ectotherms which use outside sources to regulate temperature.

What spectrum can insects detect?

The UV spectrum

What functions of insects does the endocrine system control?

Cuticle sclerotization, Osmoregulation, Egg Maturation, Metabolism, Heart Rate.

What is the difference in indirect and direct fertilization?

Indirect fertilization - Male deposits spermatophore that the female later picks up.

Direct fertilization - Internal sperm transfer that increases chance of successful fertilization.

Ametabolous metamorphosis?

primary differences in adult and larva are body size and sexual maturity

hemimetabolous metamorphosis?

species specific number of molts between egg and adult stages

holometabolous metamorphosis?

immature are called larvae because they are very different from adult in body form, behavior, and habitat

What type of symmetry do Echinoderms possess?

Most adult echinoderms have radial symmetry. (Pentaradial symmetry- body parts arranged in multiples of fives or in fives)

Echinoderms skeleton?

Skeleton consist of a series of calcium carbonate plates (ossicles), and often modified into articulated spines.

What is a water vascular system and how does it work?

Series of Water filled canals and extensions called tube feet, ring canal that surround the mouth which also serves as an inlet to replace lost water, also contain polian vesicles.

What are the two stomach regions that starfish possess and how do they work?

Cardiac stomach - receives ingested food, pyloric stomach- gives rise to ducks that connect to secretory and absorptive structures.

How does regeneration work and what is it used for in starfish?

All are capable of regenerating, body parts, damaged or lost because of predation, process of regeneration takes a year or longer, wound healing begins by quickly, ceiling, body cavities. Regeneration follows this initial healing process.

How are sea urchin skeletons organized

Skeleton is made up of 10 closely fitting plates, openings for tube feet on underside of skeleton, spines, extending from skeleton are on most of the surface.

How does gas exchange work in sea urchins?

Large coelom and coelomic fluids are the primary circulatory medium. Gas exchange primarily by diffusion, where small gills around mouth are lined by cells for gas exchange and tube feet also exchange gases