Lesson 23a Flashcards
What type of symmetry do Arthropods exhibit?
Bilateral symmetry
What’s so fancy about Arthropods appendages?
They are jointed appendages!
Define Arthropods exoskeleton, and explain 6 things about it…
It’s a hardened outer covering of the body
1. Provides protection
2. Provides points of attachment for muscles that move appendages
3. Can be thick and inflexible, or thin and flexible
4. Cannot be penetrated by water
5. Exoskeletons do not expand, so animals must molt when they outgrow their exoskeleton
6. Exoskeletons are heavy
What is an Arthropods nervous system, if they have one?
They have a ventral (meaning under) nervous system
1. Two ganglia for a brain 2. Nerve cord runs from the ganglia to the posterior of the animal on its ventral side (Runs from the ganglia to the back of the animal on its stomach) 3. Many sensory organs including: eyes, olfactory receptors, and antennae
What is an Arthropod’s circulatory system, if they have one?
They have an open circulatory system: hemolymph (blood like fluid?) flows over the various cells of the body through a heart with short arteries emptying into surrounding tissues and organs
Explain about Arthropods segmented bodies…
Their segmented bodies are composed of a: head, thorax, and abdomen
1. Thorax is the region between head and abdomen
2. Abdomen is the posterior segment
3. A fused head and thorax is called a cephalothorax
How many orders is class Insecta divided into?
30 different orders
What are 5 characteristics of class Insecta?
- 3 body segments
- 6 walking legs
- Wings at some stage of their life cycle
- Pair of antennae
- Pair of compound eyes
Explain the head segment of Arthropods in class Insecta…
Head with sensory organs
a) Compound eyes: allow the animal to see in many directions at once
b) Simple eyes: detect the presence of light
c) Pair of antennae: organs that touch, smell, and sometimes hear
d) Mouthparts
(1) Labrum and labium form the upper and lower lips
(2) Mandibles are used to crush and tear apart food
(3) Maxillae are used to chew food
Explain the thorax segment of Arthropods in class Insecta…
a) Three segments: prothorax, mesothorax, metathorax
b) Six legs: a pair of legs on each segment
c) Four wings: a pair on the mesothorax, and a pair on the metathorax
Explain the abdomen segment of Arthropods in class Insecta…
a) Most insects have 10 segments; some have 12
b) Spiracles are small pores on each segment allowing air to enter the body
c) Genitalia
(1) Ovipositor: organ that allows females to deposit eggs
(2) Aedeagus: organ that allows males to secrete sperm
Explain Arthropods in class Insecta digestive system…
They have a closed digestive system
a) Foregut: stores and grinds up food
b) Midgut: nutrients are absorbed through digestion
c) Hindgut: absorbs any remaining water before elimination through the anus
How do Arthropods from class Insecta breath?
Via a tracheal breathing system is an elaborate system of tubes that runs through the insect
a) Air enters through spiracles on the body and passes to the trachea
b) Air is then passed into smaller and smaller tubes that provides oxygen to the tissues and removes carbon dioxide waste
Explain Arthropods from class Insecta circulatory system, if they have one…
They have an open circulatory system
a) Used for moving cellular waste products out and delivering food to tissues for energy (not for oxygen!)
b) Long, tube-like heart for pumping blood
How do Arthropods from class Insecta reproduce?
Via sexual reproduction: insects have either male or female reproductive organs
-Females store sperm deposited by males, and eggs are fertilized as they are laid
