24 Questions
What major event in Earth's history is associated with the diversification of insects?
The appearance of the first land plants
Which group of animals is characterized by the calcification of an internal skeleton?
echinoderms
What is the primary method of movement used by the animal you observed in salt water?
Periodic jet of water
What is the approximate time period when insects underwent a significant diversification?
450 million years ago
Which of the following groups is NOT characterized by the calcification of an internal skeleton?
urochordates
What is the environment in which the animal was observed using a periodic jet of water?
Salt water
What characteristic of animals arose after the cnidarians?
Three embryonic layers
What is the most correct description of the ancestor of the animal clade?
A choanoflagellate
What is the main reason why J.B.S. Haldane said that the Creator has an inordinate fondness for beetles?
Because most species of animals are beetles
Which of the following is not a characteristic that arose after the cnidarians?
Two embryonic layers
What is the characteristic that distinguishes animals from other multicellular organisms?
Development of a dorsal hollow nerve cord
Which of the following is a possible ancestor of the animal clade?
A choanoflagellate
What characteristic is likely to identify an animal as a Cephalopod?
Having tentacles and an external shell
What problem is posed by the rigid exoskeleton of some ecdysozoans?
It cannot grow as the animal's body grows
What is a characteristic of chordates that distinguishes them from other animals?
The development of a dorsal hollow nerve cord
Which of the following is NOT a characteristic of ecdysozoans?
Having a dorsal hollow nerve cord
What is a possible advantage of having a rigid exoskeleton?
It provides protection and support
What is a characteristic of animals that have a lophophore?
They are able to filter feed
What is the characteristic feature of the organism that has a thick, chitinous cuticle, molts, has six jointed appendages, and a body that is divided into a head, thorax and abdomen?
Jointed appendages
Which of the following organisms is not a member of the lophotrochozoan lineage?
Vertebrates
What is the characteristic feature of a choanoflagellate?
Flagellated cell
Which of the following organisms has a body that is divided into a head, thorax, and abdomen?
Hexapod
What is the characteristic feature of a nematode?
Molting
Which of the following is an example of a lophotrochozoan?
Mollusks
Study Notes
Evolution of Insects and Chordates
- The diversification of insects about 450 million years ago corresponded with the appearance of the first land plants.
- The calcification of an internal skeleton is characteristic of echinoderms.
Characteristics of Animals
- In the history of animals, bilateral symmetry and three embryonic layers arose after the cnidarians.
- The ancestor of the animal clade was probably a choanoflagellate.
Beetles and Insects
- Most species of animals are beetles, which is why J.B.S. Haldane quipped "the Creator has an inordinate fondness for beetles."
- A rigid exoskeleton in some ecdysozoans has protective and supportive advantages but poses the problem of not being able to grow as the animal's body grows.
Chordates
- A major change in the evolutionary lineage leading to the chordates was the development of a dorsal hollow nerve cord.
- The ancestor of the chordates was probably a ciliated protist.
Test your knowledge on the evolution and development of animals, including the characteristics that arose after cnidarians and the formation of internal skeletons. Assess your understanding of embryonic layers and dorsal hollow nerve cords.
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