BIOL 101 Lecture Notes - Lecture 14: Hydrolysis, Multinucleate, Relaxed Muscle

52 views6 pages
13 Jan 2016
Department
Course
Professor
Arthropods I – Lecture 14 Notes
Biol 111 – Organismal Biology
Arthropods:
Protostome group: Ecdysozoans
E.g. Priapulid worms, horsehair worms, loricifera,
tardigrades, onychophora
Most diverse/largest eukaryotic group
Very abundant (10^8 individuals alive at any given time)
Reduced segmentation
Body regions
Abdomen, thorax, head
Jointed appendages
Specialized functions
Rigid exoskeleton
Ecdysozoan; moulting animal
Arthropod Diversity:
Crustaceans, diplurans, arachnids, etc.
Insects:
Dytiscus: predaceous diving beetle
Adults collect air under wings & use this to breathe
underwater
Honey bee has complex social life
Worker bees dance to communicate location of
new food source
Exoskeleton:
Non-living
Secreted by epidermis
Covers all external surfaces, digestive tract & tracheae
Composed of layers
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in
Chitin, protein + CaCO3 (in crustaceans)
Advantages of Exoskeleton:
Physical support
Place for muscle attachment
Physical protection
From abrasion, predation, parasite entry
From dessication
Location of pigments (camou>age, warning coloration,
mating)
Jointed appendages & exoskeleton allow faster
locomotion
Opportunity to change morphology between larval &
adult stages
Disadvantages of Exoskeleton:
In>exible & heavy (if thick & protective)
Continuous growth in size if not possible
Must be periodically shed (moulted)
Requires energy to form & shed
Prevents use of cilia as e@ectors
Respiration through skin not possible
Spiracles (pores) & tracheae (tubes)
Discontinuous Growth:
Mass grows continuously, but size changes in stepwise
fashion
Clams do not experience moulting invents
Skeletons:
1. Hydrostatic skeleton
Ex. Cnidarians, “worms,” shell-less mollusks
2. Exoskeleton
Ex. Shelled mollusks, arthropods
3. Endoskeleton
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class
Class+
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
1 Booster Class