Invertebrates (2)

Question 1

What are the most successful groups of animals and what percent do they make up?

Answer 1

Insects. Nearly 75% of all identified animal species are insects; there may be as many as 30 million insect species.

Question 2

What are the body parts of an insect?

Answer 2

The body of an insect typically includes:

-a head,
-thorax,
-abdomen,
-three sets of legs, and
-wings (in most).

Question 3

What makes insects the most successful group of animals?

Answer 3

The extraordinary success of insects is due to:-

-body segmentation
-an exoskeleton
-jointed appendages
-flight
-a waterproof cuticle
-a complex life cycle with short generations and large numbers of offspring

Question 4

What do 80% of insects’ life cycles often include?

Answer 4

Metamorphosis. Larva transforms from a pupa into an adult.

Question 5

What is the other process insects undergo as a life cycle?

Answer 5

Other insect species undergo incomplete metamorphosis, (transition from larva to adult is achieved through multiple molts, but without forming a pupa)

Question 6

What role does an insect’s appearance play in their success and where did these traits result from?

Answer 6

Specialized appendages and protective color patterns have also played a major role in this group’s success.

These traits frequently result from evolutionary changes in the timing and location of homeotic gene expression.

Question 7

What are the morphological features of echinoderms?

Answer 7

Echinoderms(phylum Echinodermata) are:

-a diverse group including sea stars sand dollars, and sea urchins
-slow-moving or sessile
-all marine
-radially symmetrical as adults
-deuterostomes

Question 8

What kind of skeleton do echinoderms have and what are they made of?

Answer 8

Echinoderms have an endoskeleton of hard calcium-containing plates under a thin skin.

Question 9

What kind of vascular system do echinoderms have and what other unique abilities do they have?

Answer 9

A water vascular system based on a network of water-filled canals that branch into extensions called tube feet, and the ability to regenerate lost arms.

Question 10

What are the characteristics of phylum chordata?

Answer 10

Chordates (phylum Chordata) are defined by:

• Dorsal, hollow nerve cord
  -A flexible, supportive, longitudinal rod the notochord
  -pharyngeal slits
  A muscular post-anal tail.

Question 11

How are tunicates and lancelets characterized?

Answer 11

Tunicates and lancelets:

-do not have a backbone and
-use their pharyngeal slits for suspension feeding

Question 12

What are the simplest chordates?

Answer 12

The simplest chordates are lancelets and tunicates, marine invertebrates.

Question 13

Explain the features of an adult tunicate and larva tunicate.

Answer 13

Adult tunicates are stationary and attached, while the tunicate larva is a tadpole-like organism.

Question 14

How are invertebrates valuable to us?

Answer 14

1. Freshwater mussels filter and improve water quality in natural ecosystems and reduce the cost of water treatment for human uses.
2. Reef-dwelling cone snails produce a powerful painkiller in their venom.
3. Most flowering plants are pollinated by animals, chiefly insects.