New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Chapter 1 notes

by: Wolfjedi

Chapter 1 notes Bio 335

University of Phoenix
GPA 2.0
View Full Document for 0 Karma

View Full Document


Unlock These Notes for FREE

Enter your email below and we will instantly email you these Notes for Entomology

(Limited time offer)

Unlock Notes

Already have a StudySoup account? Login here

Unlock FREE Class Notes

Enter your email below to receive Entomology notes

Everyone needs better class notes. Enter your email and we will send you notes for this class for free.

Unlock FREE notes

About this Document

Arthropod overview
Class Notes
entomology notes, week 1, Arthropoda




Popular in Entomology

Popular in Biology

This 8 page Class Notes was uploaded by Wolfjedi on Saturday September 24, 2016. The Class Notes belongs to Bio 335 at University of Phoenix taught by in Fall 2016. Since its upload, it has received 14 views. For similar materials see Entomology in Biology at University of Phoenix.

Similar to Bio 335 at University of Phoenix


Reviews for Chapter 1 notes


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 09/24/16
Fundamentals of Entomology Chapter 1 notes I Arthropods differ from many other invertebrates by having the following characteristics: a Bilateral symmetry b An exoskeleton with chitin c Externally segmented bodies and embryologically one pair of appendages per segment d Appendages modified for feeding e A hemocoel instead of a coelom f No cilia g A ventral nerve cord and dorsal brain II Arthropods are an ancient group of animals that first appeared from the precambrian to the cambrian divisions of Earth's history. a Two major lines have survived to this day and are classified as subphyla i Mandibulata; those that have well developed mandibles ii Chelicrata; those that utilize chelicerae II Arthropods represent an extremely successful group of animals. a Among the earliest terrestrial animals, although originally marine. Segmentation and Tagmosis I The ancestors of arthropods were bilaterally symmetrical and had their major sensory structures located at the anterior end of the body to perceive the forward environment. a Body probably consisted of 20 or 21 metameres, or segments. b Segmentation did not represent complete divisions of the body, only muscle organization within exoskeleton. c Ailmentary canal had two openings i Anus ii Mouth b Present day arthropods evolved from this archetype. II Arthropod bodies are specialized into functional regions or tagma, a process termed tagmosis. a Type 1; The anterior six segments evolved into the head (sensory, feeding, and coordination centers), and the remaining segments, or trunk, retained their role including locomotion (centipedes and millipedes). b Type 2; the anterior 8 (spiders) to 4 segments (crayfish) became modified into a cephalothorax or prosoma (sensory, feeding, coordination, and locomotor center), and the remaining segments became the abdomen or opisthosoma and commonly lost most of their appendages and role in movement. c Type 3; found in insects and many crustaceans, resulted in three body regions, the head (sensory, feeding, and coordination center), the thorax (locomotion), and the abdomen. i Localization of the locomotor area into the thorax or cephalothorax reduced undulation tendencies, such as those in centipedes, because the propulsion force of long legs is applied to a small area. Exoskeleton I The outer surface of terrestrial animals must protect the body and slow down either water uptake or loss from the body. a Often accomplished by the production of slime or mucoprotein that covers the body surface. b In arthropods, the covering has been modified into a solid structure, the many-layered exoskeleton, or integument. i Covers and protects the entire external surface ii Is invaginagated into the body to line the tracheal system, the anterior and posterior sections of the digestive system, portions of the reproductive system, and to provide internal braces and the muscle attachment bases. b Integument consists of; i Basement membrane, a layer of epidermal cells ii An externally secreted structure, the cuticle 1 Contains up to one-half the dry weight of an insect 2 Major compound is chitin, a polymer of N-acetyl-D-glucosamine and closely related cellulose. a Has a tannish color and is flexible b Results from the addition of certain hardening material to form a chitin- protein complex of microfibers in the cuticle. i In insects and arachnids = quinones cross-link the chitin-protein microfibers into a plasticlike sclerotin, a material that is both strong and light. 1 Termed sclerotization ii In crustacea and diplopoda = add calcium 1 Termed calcification II The outermost, multilayered, yet extremely thin epicuticle, consisting of lipids and polyphenols, provides waterproofing and also protection for the epidermal cells when the new cuticle is deposited during molting. a Inside this is the hardened exocuticle, the layer produced by sclerotization, and the innermost flexible and recyclable endocuticle. II Finalized suit of armor is the result of localized areas becoming specialized in the presence and thickness or absence of these layers. a Areas with thick exocuticle = sclerites i May be braced further by creases or sulci. b Flexible regions between sclerites permit movement i Consist primarily of endocuticle and are referred to as membrane. b Pore canals extend through the procuticle and aid in the deposition of portions of the epicuticle. c Dermal gland ducts also extend from the cellular layer to the external environment through the integument. II Deposition of an exoskeleton results in modifications to the sensory systems a Most develop as a part of the integument b Extend through integument into hairlike projections, the setae. i Most are solid and innervated at their base to detect tactile movement ii Some are hollow and detect chemicals entering them through lateral pores iii Others include; 1 Tympanic organs (hearing) 2 Temperature-sensitive organs 3 Photoreceptors (light). b Others form platelike pressure pads. II Benefits of integument a Protection from chemicals i Except strong acids and bases b Retardation of water movement both out of and into the body c High protection from physical damage and abrasion d Can form concealing colors and shapes for avoiding detection by predators e A barrier to pathogens and many predators f Reservoir for some waste products g Structure for attaching a musculature system with good leverage. h Cuticle also resists the harmful effects of ultraviolet rays. II Disadvantages a Need for special modifications for gaseous exchange and sensory pickup b Restriction on growth and maximal size i Only a limited amount of protoplasm can be added until it becomes restrictive b Shedding or molting exposes the individual to physical and chemical forces from which it was previously protected i Water loss becomes critical during this period ii New exoskeleton must be larger than the old one or process would be self-defeating II Arthropods are small compared to most vertebrates a Advantages i Individuals require less energy and time to complete development ii Less energy is needed to sustain life as both individuals and as populations iii Easier to find protection from predators and other environmental extremes iv Greater number of ecological habitats are available for exploitation v Muscular action is more efficient vi Solar heat can be used to heat the body vii Random dispersal by wind is accomplished with great ease viii Gravity has less effect b Liabilities i Predation ii Being hit or trapped in rain droplets iii Being captured iv Potential for water loss is greater Species numbers I Arthropods have great adaptability and have radiated into many aquatic and most terrestrial habitats. a Trilobites, followed by crustacea, illustrate the dominant role of this phylum in the marine environment. b Insecta and arachnida have done the same in the terrestrial realm. c More than 80 percent of known animal species are arthropods i Five major subgroupings or classes Arthropod Classes I Arachnida a Spiders, mites, ticks, scorpions, pseudoscorpions, harvestmen, whipscorpions, and sunspiders. b Posess chelicerae and pedipalpi i Chelicerae; believed to be appendages of the third body segment, usually modified into predatory organs. 1 Have 2 or 3 segments 2 Most have an opposable "thumb" whereby the prey may be grasped and torn apart. 3 Exceptions; many parasitic mites, ticks, and spiders ii Pedipalpi 1 Variously modified and multisegmented. 2 In scorpions and pseudoscorpions, pedipalpi are chelate and are greatly enlarged for capturing prey. 3 Become copulatory organs in male spiders a Are sensory structures and form the base of a preoral cavity in most spiders. b Lack antennae c Have 4 pairs of legs as adults, a cephalothorax, and an abdomen d Except for the mites and ticks, specialization only occurs for a carnivorous diet e Most are terrestrial II Silk is produced by many arachnids and has many uses. a Silken chambers are spun over eggs and form protective retreats for many mites, pseudoscorpions, and spiders. b Young spiders, soon after hatching, draw out silken strands that are captured by the wind and transport them from one habitat to another. i Called ballooning b Males spin sperm webs i Sperm is deposited onto them and subsequently withdrawn by the copulatory pedipalpi. b Draglines are spun by most spiders and often prevent injury when spiders fall from a precarious site. c Silk is used to capture prey d Silk comes from abdominal spinnerets and is formed into a snare (web) for entangling unsuspecting invertebrates II Most arachnids are carnivorous, exceptions may be seen in ticks and many mites. a Hard-bodied ticks hatch in great numbers and attach themselves to a host by their mouthparts. i They eat, molt into a nymphal stage, eat, molt into adult stage, eat. ii Some species can transmit diseases to humans, wildlife, and domesticated animals. 1 Rocky Mountain spotted fever 2 Lyme Disease b Many mites are also parasitic during some stage of their life cycle. i Most are located on the hosts outer covering 1 Chiggers 2 Skin mites (demodex) a Inhabit pores and skin b Affect humans, pets, and livestock ii Most are not parasitic, but feed on plants and other arthropods. 1 Phytophagous mites penetrate plant tissues and use their chelicerae to withdraw such liquids as sap, interstitial fluids, or lysed cells. 2 Detrimental to crops and shrubs a Feeding and disease transmission. ii Mites that feed on other mites, insects, and arthropod eggs and are beneficial to humans. 1 More than 20 million cases of asthma are estimated to be caused by exposure to these mites. II Small arachnids obtain oxygen through their exoskeleton and/or minute tracheal tubes. a Large species, such as scorpions have book lungs to increase the surface area for gaseous exchange, yet minimize water loss by maintaining this expansion internally. i Internal sacs with many leaflike membranes b A few species are aquatic and utilize gills II In most arachnids, sperm is transferred inside a spermatophore a Spermatophore; an often-sclerotized "suitcase". II Development takes two paths after fertilization. a Many, such as spiders and scorpions, hatch from eggs resembling the adult, and the successive molts produce only minor changes. b In others, such as the mites, more drastic changes take place as the young pass through successive larval (three pairs of legs) and nymphal (four pairs of legs) stages. i In both, life cycles vary, but duration is normally a function of size and temperature. 1 Many mites expire after a few months, but a large tarantula may survive for more than 20 years in the tropics. II In addition to the bites and stings of mites and ticks, those by other arachnids may be painful and are sometimes dangerous to humans. a Spiders possess poison glands that empty through a duct into the terminal segment of the chelicera. i Normally used to kill prey, but can also be harmful to humans and other vertebrates. b Some scorpions also have toxins harmful to humans i Injected by the sting located at the terminal end of the abdomen II Arachnids are subdivided into orders on the basis of modifications of the chelicerae and pedipalpi and the presence or absence of abdominal segmentation, as well as the presence of specialized adaptations such as stings. Crustacea I Crustacea had an ancient origin, showing up at the beginning of the Cambrian division. II Approximately 42,000 species III Mandibulate, possessing as their major structures appendages called mandibles. IV During some stage in their life history, their appendages are branched or biramous. V Two pairs of antennae, often used in swimming by some minute species VI Two pairs of maxillae that aid in feeding. VII Tagmosis is extreme but is usually comprised of either a head, thorax, and abdomen or a cephalothorax and abdomen a Some species have little or no divisions of their body into body regions II Harden their exoskeleton by the addition of calcium salts III Majority are marine, some freshwater, few terrestrial a Oxygen often must be obtained from water where it is in relatively low concentrationn i Small individuals take in oxygen through their body surface ii Large individuals have gills, expansions from their legs, which constantly circulate water across the surface area of the gills to aid in oxygen uptake. II Majority of crustaceans hatch from eggs in a shape very unlike the adult and pass through a series of larval stages. a Simplest is the nauplius. i Consists of an unsegmented body, three pairs of appendages, and a single median eye. ii Species that initiate life with this stage usually progress to the adult through a series of progressive steps separated by molts. 1 Segments and appendages are added at a "budding zone" near the posterior end of the body until the predetermined adult number is reached. a Anamorphic development ii Three swimming appendages of the original nauplius eventually become two pairs of antennae and the mandibles of the adult. b Some of the more advanced Crustacea hatch as a specialized larvae and bypass the nauplius through comparatively large changes at each molt. i Ex. Crabs have a zoea larva in which many of the abdominal segments are already present at hatching and the mouthparts are functional. II Food varies according to the size of the individual a Larval stages and small adults = other plankton such as diatoms b Larger crustaceans = usually carnivores or scavengers, although a few are parasites. Chilopoda I Centipedes have a long body divided into a head and a multisegmented trunk. J a Head has a pair of moderately long antennae, a pair of mandibles, and two pairs of maxillae b With the exception of two terminal segments, the remaining segments each have a single pair of legs. i Some species have short legs ii Other species have elongated appendages for running in more open spaces iii First pair of legs behind the head is modified into poison claws or toxicognaths used in capturing invertebrates on which the centipedes feed. b Eggs are deposited either singly or in groups i If they are oviposited in groups, the female usually guards the eggs. ii Primitive species hatch with few segments and add segments during successive molts 1 Anamorphic development 2 Max number of leg-bearing segments is 15 ii More advanced centipedes are born with the same number of segments as the adult 1 Epimorphic development 2 Include species with the greatest number of segments (up to 190) and appendages 3 Molting results only in a size increase a Max size is approximately 275mm recorded for one species in South America. ii Centipedes usually hide during the daytime but are active at night. 1 Food consists of other arthropods, earthworms, and slugs. Diplopoda I The millipedes represent another group that has a body differentiated into a head and trunk. a Head contains a single pair of short antennae, a pair of mandibles, followed by a single pair of fused maxillae, the gnathochilarium. b Most trunk segments are actually diplosegments i Fused dorsally but not ventrally so that each segment appears to have two pairs of appendages ii Genital pore is located anteriorly b Eggs are deposited in groups of 25 to 250 in soil or moist humus. i Larvae possess only three pairs of legs at hatching but diplosegments are added by anamorphosis in groups of three or more at a molt until the predetermined number of segments is reached. b Maximum number of legs known is 375 pairs, but most have fewer than 50. c Longest millipede is 300mm d Life cycle is anywhere from 1 to 7 years. e Molting occurs in earthen chambers in which water loss is minimized and in which protection from predators is maximized. f Exoskeleton is hardened by incorporating calcium carbonate. g Most are found in rotting logs, leaf litter, humus, and under stones i Feed mainly on decaying vegetative material and fungi. b Slow moving due to number of legs. c Most secrete noxious fluid from specialized glands located along the length of the body i Repels predators Insecta I Taxonomists do not always agree to what an insect is. a Several orders are enigmatic but these have been included as insects because they are at least closely related to them. II Defined as arthropods that, as adults, have three body regions or tagma, three pairs of thoracic legs, and a pair of antennae, and they feed by mandibles. a Consist of 19 or 20 segments b Only invertebrates to possess wongs II Most are terrestrial III Development is epimorphic, except in the order Protura, and no new segments are added after hatching from the egg. a Changes vary from minor (incomplete metamorphosis) to drastic (complete metamorphosis) b Most complete development within a year or less, but require up to 17 years to mature. II Why have insectan species become so successful? a Their small size b Modification and exploitation of appendages into the many types of mouthparts and locomotion-food gathering legs.. c Extensive development of complete metamorphosis in which the immatures and adults have evolved to feed on different foods and, hence, ephemeral sources can be exploited with little competition among individuals of the same species. d Rapid life cycles e The many different species-isolating mechanisms involving genital, hormonal, and behavioral modifications. f Seasonal variations wherein one generation can vary from another. g Possession of wings during the adult reproductive stage, particularly the type that can be folded when not in use.


Buy Material

Are you sure you want to buy this material for

0 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Kyle Maynard Purdue

"When you're taking detailed notes and trying to help everyone else out in the class, it really helps you learn and understand the I made $280 on my first study guide!"

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.