Lesson 2B Internal Form and Function

Question 1

What are the three parts of the digestive tract?

Answer 1

Foregut: food is ground up by proventricular teeth before moving to midgut.

Midgut: epithelial cells secrete digestive e3nzyme . most of digestion occurs here.

Hindgut: peristalsis conveys undigested food waste to the rectum. rectal papillae extract moisture in some insects.

Question 2

What special structures are found at the junction of the midgut and the hind gut and what is their function?

Answer 2

Malpighian Tubules ; absorb waste that is released into the blood as a result of cells metabolizing nutrients.

Question 3

How does the respiratory system in insects work to get oxygen to their tissues

Answer 3

Air enters through Spiracles on the thorax and abdomen.

Spiracles lead to Trachea, which run along body.

Trachea ramify into smaller and smaller tracheoles

Tracheoles to tissues (gas exchange)

pg 460

Question 4

What is the organ that function as “heart” in insects and where is it located in the body cavity?

Answer 4

Dorsal Vessel; starts on top of the alimentary canal and goes to from the head to the abdomen.

Question 5

What is the general name for the insect body cavity?

Answer 5

Hemocoel; a hermetically sealed cavity in lieu of blood vessels.

Question 6

What is the term used to describe when an insect produce offspring without mating?

Answer 6

Parthenogenesis

pg 461

Question 7

What are the life stages in an insect that undergo incomplete metamorphosis

Answer 7

Egg; Naiads; Adult

Mayflies EphemeropteraI

pg 462

Question 8

What life stages are present in an insect that goes through complete metamorphosis?

Answer 8

Egg; Larvae; Pupa; Adult

examples: Flies Diptera; Beetles Coleoptera

Question 9

What advantages does an insect achieve in undergoing the different stages of the complete metamorphosis?

Answer 9

The primary advantage of complete metamorphosis is that larval and adult insects do not have to compete for the same food source because they are anatomically different.

Question 10

Draw a diagram and describe the insect molting process at the cellular level up to the sclerotization or hardening of the new exoskeleton of the freshly emerged insect.

Answer 10

1. Exoskeleton separated from underlying epidermal cells by an enzyme.
2. lower layer of old exoskeleton is digested by enzyme.
3. enzyme reabsorbed into new epicuticle.
4. epidermal cells undergoing rounds of active cell division. This results to a larger surface area to facilitate growth for the next metamorphic stage.
5. Formation of new exoskeleton (soft until exoskelton is shed)
6. insect cracks exuviae
7. insect exits exuviae
8. insect expands exoskeleton to full size where it is hardened.
   https: //canvas.ubc.ca/courses/52107/files/12200458?wrap=1