Invertebrates 5

Question 1

What group encompasses Nematoda, Tardigrada, Onychophora, Arthropoda?

Answer 1

Ecdysozoa

Question 1

Facts about arthropods?

Answer 1

-Live in all environments and consume a variety of foods
-Segmented with regions fused to form tagmata
-Most diverse eukaryotic group

Question 2

Define Tagmata

Answer 2

Distinct region of an organism such as the head, thorax or abdomen

Question 3

what are the four major groups of arthropods?

Answer 3

1. Crustaceans
2. Myriapods
3. Insects
4. Chelicerates

Question 4

Segmented body plan of Arthropods

Answer 4

1. Segments fuse to form tagma
2. Diversity of arthropods is based on the variation in number and function of body segments

Question 5

Jointed Appendages

Answer 5

Appendage: projecting part of an organism
-Biramous(branched) or Uniramous(unbranched)
- Each body segment is associated with a single pair of appendages, appendages can form parts such as antenna, mouthparts or reproductive organs

Question 6

Highly developped sense organs

Answer 6

• Highly cephalized (concentration of sense organs at the anterior end of the organism)
  -Elaborate sensory organs including: compound eye, antennae, sensitive hairs

Question 7

Rigid Exoskeleton

Answer 7

-Non living
-Encloses and protects the entire body including organs and digestive/respiratory tract
-Made up of protein and chitin
-Secreted by the epidermis
-Crustaceans contains calcium

Question 8

3 Advantages of a rigid exoskeleton

Answer 8

1. Physical support and protection from predation, desiccation, or parasite entry
2. Provides the opportunity for organisms to change morphology between larval and adult stage(metamorphosis(cocoon to butterfly))
   3.Exoskeleton is the location of pigments, they allow for camouflage, warning colorations and mating signals

Question 9

5 Disadavantages of a rigid exoskeleton

Answer 9

1. Inflexible and heavy
   2.Continuous growth in size is not possible because as the animal grows the exoskeleton becomes to tight as it does not grow, the exoskeleton must be shed(moulting)
2. The moulting process is very energy costly
3. Crustaceans require a water body that contains a certain amount of calcium for their exoskeleton
4. Respiration through the skin is not possible due to exoskeletons therefore animals must create specialised structures such as spiracles(pores) & trache(tubes) to respire

Question 10

Discontinuous Growth

Answer 10

Mass grows continuously but size grows in a step wise function (after every moulting process)

Question 11

Do insects undergo moulting as adults?

Answer 11

No, instead they metamorphosize into adults

Question 12

Complete Metamorphosis? How many stages? What is each stage?

Answer 12

-Four stages
1. Egg
2.Larva
3.Pupa(resting stage)
4. Adult

Question 13

What types of arthropods undergo metamorphosis?

Answer 13

-Butterflies
-Bees
-Moths
-Beetles

Question 14

Incomplete metamorphosis? How many stages? What is each stage?

Answer 14

-3 stages
1. Egg
2. Nymph
3. Adult

Question 15

Incomplete vs complete metamorphosis

Answer 15

Complete:
- Habitat change
-Abrupt changes
-resting stage
-4 stages
Incomplete:
-No habitat change
-Gradual changes
-No resting stage
-3 stages

Question 16

Arthropods that do incomplete metamorphosis?

Answer 16

-Grasshoppers
-Crickets
-Termites

Question 17

What did Wigglesworths experiment prove?

Answer 17

The substance that controls moulting is produced in the brain and diffused slowly to the body

Question 18

What are hormones?

Answer 18

Chemical messengers secreted by endocrine cells and distributed by blood to target cell which initiates a response in the body

Question 19

What is integration between nervous and endocrine systems?

Answer 19

Environmental stimulus activates sensor cells which produces a neural signal that stimulates the central nervous system to produce a hormone. This hormone is secreted into the bloodstream and elicits a response in the effector cell that then sends another response to the sensor cell to create a feedback loop.

Question 20

Name the 3 hormones important for moulting in arthropods?

Answer 20

1. PTTH
2. Ecdysone
3. Juvenile Hormone

Question 21

PTTH

Answer 21

-Produced and stored by the brain
-Production is influenced by environmental cues
-Controls the activity of the prothoracic gland which secretes ecdysone

Question 22

Ecdysone

Answer 22

-Produced by the prothoracic gland
-Secreted into the blood and transported to target cells
-Target cell are in the epidermis
-Response = moulting(ecdysis)
-Tells brain to stop producing PTTH

Question 23

Juvenile Hormone

Answer 23

-Secreted into the general circulation by non neural endocrine cells
-Controls metamorphosis

Question 24

High concentration of Juvenile Hormone

Answer 24

Insects remain larval and do not become pupa

Question 25

Low concentration of juvenile hormone

Answer 25

Insect is triggered to moult by ecdysone to pupa

Question 26

Respiratory system in Insects

Answer 26

-First invertebrates to colonize land
-Have tracheal tubes with openings to the exterior that carry O2 to the body cells

Question 27

Respiratory system in Crustaceans

Answer 27

-Have gills
-Small molecules of oxygen can be pulled into the bloodstream as they pass over the gill surface

Question 28

Respiratory system in Chelicerates

Answer 28

-tracheal tubes
-book gills(found in the abdominal cavity)
-Book lungs(used for atmospheric gas exchange)

Question 29

Circulatory system in Arthropods

Answer 29

-Open system(hemolymph(blood) fills the body cavity)
-Coelom is reduced due to the exoskeleton and divided into small areas filled with blood that soak the organs in blood

Question 30

Advantage of an open circulatory system

Answer 30

-Requires less energy to distribute blood than compared to a closed system

Question 31

Musculo-skeletal system in arthropods

Answer 31

Paired muscles operate their joint exoskeleton

Question 32

Endocrine Pathway

Answer 32

Stimulus, tells the endocrine cell to produce a hormone, this hormone then binds to a specific cell causing the cell to change activity. Once the cell changes its activity it will release a response to stop the endocrine cell from producing the hormone.