1: Arthropods: Arachnids

Question 1

Terrestrial cherlicerates are more commonly known as what?

Answer 1

Arachnids

Question 2

Describe repro and parental care in Scorpions

Answer 2

• Indirect internal fertilisation
• Females give birth to live young (unusual in arachnids) & broods young

Question 3

How are the chelicerae modified in Spiders?

Answer 3

Modified into fangs → neurotoxins

Question 4

Give 2 key features of chelicerae

Answer 4

Appendages near the mouth, often modified into pincers or fangs

Question 5

Describe the Spinneret

Answer 5

• Structure found in abdomen of spiders used to spin silk
• Silk protein = fibroin

Question 6

What sort of excretory system do spiders use?

Answer 6

Malpighian tubules

Question 7

Describe mating in Spiders

Answer 7

Internal, indirect fertilisation
1. Male produces a pouch made from silk, he releases sperm into the pouch
2. Sucks this up using pedipalp
3. Penetrates female using pedipalp
- Sometimes during mating the pedipalp can be snapped off!
- Females usually larger than males
- Male sometimes eaten by female after mating (lol)

Question 8

Give an example of extreme sexual dimorphism in spiders

Answer 8

Nephila sp (orb weaving) spider
- Huge size disparity
- Good for females to be large to produce more eggs
- Males smaller, more agile and can escape more easily

Question 9

Describe mites and give some examples

Answer 9

• Can be free living and/or parasitic

Examples:
Ear mites
Dust mites → humans
Varroa → honey bees
- Mites feed on larval form & adults
- Weaken bees
- Transmit diseases

Question 10

Describe ticks

Answer 10

Ectoparasites that feed on blood
can transmit diseases e.g Lyme disease (spirochete)