Diversity of Life 2 Lab 8 - Part 2

Crustacea, Echinodermata, Chordata

When does Naplius larva stage occur in crustaceans?

First larval stage

2 characters and associated states that identify immature crustacean

1. Eye structure - 1 eye

2. Head - 3 segments

How is the carapace adaptive in Ostracods?

• Large brood chamber, camouflage, protection, streamlined design

• Helps with interstitial habitat: very small to fit in between sand grains

2 character states for Lobster claws

Crushing vs manipulating

Crab eye character state

Stalk eyes

What is the adaptive advantage of the eye character state for a crab that possesses it?

360 degree vision

Compare the character states of the abdomen of a crab vs a lobster

Crab: small and tucked away, used primarily for reproduction

Lobster: visible muscular tail

What additional appendage is exhibited by shrimps?

stalk eyes and claws

Like insects, crustaceans do what in order to grow?

Molt

What do aquatic isopods, sowbugs, and pillbugs do when they feel threatened?

“Curl up” aka conglobation

What traits do aquatic isopods, sowbugs, and pillbugs possess that make the term “bug” incorrect?

Possess gills and must live in moist environment

Have 14 legs vs 6 (hemiptera)

What are barnacles thoracopods adapted for?

Feather-like cirri used as a “feeding net”; trap and sweep method

What are 2 characters that identify Daphnia as crustacean

1. Chitinous carapace

2. Biramous antennae

How are the tube feet of the feather star put to good use despite them being planktonic?

Locomotion; also part of the water vascular system

Species in class Crinoidea will always have a multiple of ___ arms.

5

Since they do not use their tube feet for locomotion, why do Brittle Stars have tube feet?

Adhesion, respiration, sensory perception, collecting food

What is the major anatomical difference between sea and brittle stars?

Brittle stars have slender arms and the organs are all in the central disc. Sea stars’ organs extend into their arms

Aristotle’s Lantern and its uses

Mouth with teeth that are self-sharpening

What is the common name for the sea cucumber that refers to their life history?

“Earthworm of the sea”

What are sea cucumbers 2 defense mechanisms?

1. toxin production

2. squeeze into small spaces

How are the tube feet of sea cucumbers modified or adaptive?

Buccal tentacles used to sort through sediment

On what basis are Tunicates considered a sister group to all vertebrates?

Post-anal tail and a hollow dorsal nerve chord