BIO 245 - Week 4-5 - Exam 2

Higher ____ ratios

Surface area and volume

Surfaces are

Interface between animal and environment

All are driven by surface area

Gas exchange, water loss, and temperature exchange

What is a huge threat to an insect?

Water loss

Insects are?

Ectotherms

Integument

Outer covering of an insect

• Exoskeleton

• Internal supports and muscle attachment

What is a part of the integument

Wings

Integument lines what?

Tracheal tubes (breathing), foregut, and hindgut

What are the benefits of the integument

All of the above

What are the downsides of the integument

All of the above

What are the major components of an insect’s exoskeleton?

Chitin and Proteins

Chitin

Long chain polysaccharide

Proteins

Used for tanning or sclerotization

Integument =

Epidermis and cuticle

Cuticle =

Epi + Exo + endocuticles

Epicuticle =

Includes wax layer, cement layer

Exocuticle =

Chitin in protein matrix; flexible

How can cuticle be both rigid and flexible?: Exocuticle

Chitin linked with protein chains making it rigid

How can cuticle be both rigid and flexible?: Endocuticle

Less protein and remains flexible

How can cuticle be both rigid and flexible?: Rigid regions of the cuticle have a?

Substantial exocuticle layer

How can cuticle be both rigid and flexible?: Flexible regions have?

Little exocuticle

The cuticle is also?

Waterproof

The layer that includes the waterproof wax layer is the?

Epicuticle

Why is a waterproof cuticle developed?

Allows insects to live on dry land and prevent desiccation (water loss)

Sclerites

Rigid plates of exoskeleton

Membrane

Soft, flexible sections between sclerites

Tergum

Dorsal section of sclerite

Pleuron

Lateral section sclerite

Sternum

Ventral sclerite section

The head: Function

All of the above

Compound eyes

Image-forming

Ocelli

•“Simple eyes”

•0-3

•Light/dark-sensing

The head: Antennae

Chemosensation (smell and taste) and Mechanosensation (touch)

Antennae: Scape and Pedicel

“True” segment, musculature

Antennae: Flagellum

one segment but many individual flagellomeres (similar to tarsus/tarsomeres) no muscles 

The thorax is known for?

Locomotion

The thorax has?

Most major muscle groups

The thorax has what?

Wings and legs

Structure of the thorax always has?

Three sections

Where do the wings attach?

Meso and meta -notum

Thorax: Structure leg section

One per section

Tergum (dorsal section) of thorax is the?

Notum

How do you piece the structure of the thorax?

Pro-, meso-, and meta- (notum)

Legs have what parts?

Distal  Proximal

tarsus – tibia – femur – trochanter – coxa

Leg segments are modified for?

Specific functions

Wing structure is diverse

Has been modified for different functions

What are the functions of the abdomen

Digestive tract; reproductive organs; osmoregulation; mating; oviposition; sensory structures (cerci)

The Abdomen: Segments are

Often reduced or fused (can be important for ID)

The Abdomen: Sclerites (plates)

On top & bottom of each segment

•Tergites on top,
sternites below

The Abdomen: Cerci

At end of abdomen

What is cerci at the abdomen?

•Antenna-like sensory structures

•Mechanosensory (touch)

•Absent in many groups

•Sometimes modified for
other functions, e.g. earwigs (Dermaptera)

Metameres

Repeating parts

Tagmosis (Tagmata)

Merging segments into functional units

What are the basic elements of EXTERNAL body parts

• Jointed appendages

• Sclerites, separated by regions of membrane

What are the basic elements of INTERNAL body parts

• Paired nerve ganglia

• Muscles

• Coelomic Spaces

Internal anatomy major systems: Gas exchange

Respiration

Internal anatomy major systems: Food and waste

Digestive and excretion

Internal anatomy major systems: Transport

Circulation

Internal anatomy major systems: Sensory or coordination

Nervous

Internal anatomy major systems: Hormonal regulation, esp. development

Endocrine

Internal anatomy major systems: Passing genetic material to next generation

Reproductive

Respiratory system: Gas exchange

O₂, CO₂, and water vapor

Respiratory system: Does not rely on?

Circulatory system

Respiratory system: Relies on

Diffusion

•Slow

•(Limits maximum size)

Respiratory system: Therefore, tubes must deliver

Air to every cell of the body

Respiratory system: Spiracles

Openings on sides of body

Respiratory system: Trachea, Tracheal system

• Tubes throughout body

• Part of the epidermis - lined with cuticle (must shed)

Respiratory system: Does not rely on?

Circulatory system

Respiratory system: Diffusion and Ventilation

All of the above

Digestive system: Complete gut

From mouth to anus

•Allows specialization of different sections

Digestive system: Diets are extremely varied

Guts will vary

Digestive system: Section one

Foregut

Digestive system: Section two

Midgut

Digestive system: Section three

Hindgut

Digestive system: Foregut and hindgut lined with?

Cuticle (must shed)

Foregut

Food intake, storage and predigestion (lined with cuticle)

Foregut: Crop

Expandable; stores predigested food

Foregut: Proventriculus

Grinds or strains food (for solid food diet)

Midgut

Digestion and nutrient absorption (not lined with cuticle)

Midgut: Ventricles

Digestion and nutrient absorption

Midgut: Gastric caecum

Extra surface area in midgut

Hindgut

Mostly involved in excretion: absorption of water, salts, other substances from feces and urine (lined with cuticle)

Malpighian Tubules

All of the above

Circulatory system: Open

• No blood vessels

• Open to body cavity

Circulatory system: Hemolymph

Not involved in gas exchange

Circulatory system: Dorsal vessel runs

Length of the body

Circulatory system: In abdomen

Dorsal vessel is a muscular heart

•Separated by valves to ensure one-way flow of hemolymph

•Contracts in a wave back-to-front

Circulatory system: Anterior of

The heart, dorsal vessel is a simple tube (aorta)

Circulatory system: Also involved in

Defense

Circulatory system: Seals

Wounds via clotting

Circulatory system: Encapsulation

Of Circulatory system:

Circulatory system: In some groups

Contains distasteful or toxic compounds

Nervous system: This bundle of nerves is called?

Ganglia

Nervous System - Head

“Brain” is fused segmental ganglia

Nervous System - Head: Subesophageal ganglion

Fused ganglia from mouthpart segments

Nervous System: Where is most behavior controlled?

Segmental ganglia

Nervous System: Is?

Decentralized

Nervous System: Brain stimulates or inhibits ganglia

•Brain coordinates ganglia, rather than brain signaling body directly

•Headless insects can survive for days, if the neck is sealed!

Endocrine system

Hormone production, storage, release, and regulation

Endocrine system: Hormones regulate physiology

All of the above