Arthropod Diversity Flashcards Preview

Year 1 Biology Ellie M > Arthropod Diversity > Flashcards

Flashcards in Arthropod Diversity Deck (15)
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1
Q

Arthropod anatomy

A
  • Externally and internally segmented
  • Jointed appendages
  • Well developed exoskeleton
  • Tagmosis - head and trunk
  • Headshield (carapace) often present
  • Complex association of compound eyes
  • Open circulatory system: haemocoel
  • Dorsal heart and pericardium (membrane enclosing the heart)
  • Ventral nerve cord
2
Q

Segmentation of arthropods

A

Body divided into repeating units

Limbs similarly subdivided

3
Q

Arthropod exoskeleton

A
  • Made of chitin

- Harder in some areas than others where there is a need for rigidity or elasticity

4
Q

Advantages of exoskeleton

A

Protection and prevents desiccation

5
Q

Disadvantages of exoskeleton

A

Limits to size, and moulting makes arthropods very vulnerable

6
Q

Features of Arthropod moulting

A
  • Regular shedding of external cuticle
  • Facilitates the need to grow
  • Arthropods delicate at this time
  • Initially epidermis separates from cuticle
  • A fluid is then secreted between the epidermis and the cuticle, and the epidermis grows
  • A new cuticle begins to be secreted by the epidermis
  • Enzymes are then secreted in the moulting fluid, causing the shedding of the old cuticle
7
Q

Arthropod legs

A
  • Either biramous (dividing into 2 branches) or uniramous

- They serve a large range of functions

8
Q

Arthropod Hox genes

A

Transcription factors involved with anterior-posterior patterning, primarily
Play a role in segment identity
Third maxilliped in lobsters made from a mixture of the expression of UBX and Abd-A

9
Q

Internal Arthropod anatomy

A
  • J-shaped gut
  • Ventral nerve cord
  • Dorsal heart pericardium complex
10
Q

Arthropod eyes

A
  • Compound eyes are made up of many individual photoreceptors which are receiving light and creating an image
  • Camera eyes found in jumping spiders. They possess a cornea which focuses light onto receptors
11
Q

Onchyophorans

A
  • ‘Claw-bearers’ / velvet worms
  • Terrestrial worms with soft cuticle
  • Stubby animated worms with telescopic claws
  • Set of oral papillae (small round protuberance) that secrete slime for predation and mandibles
12
Q

Tardigrades

A
  • Moss piglet or water bearers
  • Marine and terrestrial
  • Stubby, claw-bearing legs, usually 4 pairs
  • Triadate pharynx (splits into 3)
  • Eutelic (fixed number of adult cells)
  • Stylet apparatus (spines to pierce tissues)
13
Q

Trilobites

A
  • 530-250 million years ago
  • Had calcimine cuticle so preserve easily
  • They had spines to protect them from predators
  • Possessed well-developed eyes
14
Q

Anomalocarids

A
  • Top predators in the Cambrian period
  • Around 1 meter long
  • Specimens had delicate spines with bristles along them, designed for suspension feeding
  • Others had mouths
15
Q

Opabinia

A

Eyes on stalks

Single appendage on trunk with claw