Question 1

Which of the following is a defining characteristic of all animals in Kingdom Animalia?

Accepted Answer

They are multicellular, heterotrophic eukaryotes that obtain nutrition through ingestion.

Question 2

During early embryonic development in animals, what is the correct sequence of stages?

Accepted Answer

Zygote → Blastula → Gastrula

Question 3

Which germ layer gives rise to the muscles and most organs in triploblastic animals?

Accepted Answer

Mesoderm

Question 4

What is the main function of the body cavity (coelom) in animals?

Accepted Answer

It cushions organs, acts as a hydrostatic skeleton, and allows organs to grow and move independently.

Question 5

Which of the following statements about animal symmetry is correct?

Accepted Answer

Bilateral symmetry allows for the development of a head and tail (anterior and posterior) region.

Question 6

Which of the following best describes the difference between protostome and deuterostome development?

Accepted Answer

In protostomes, the blastopore becomes the mouth; in deuterostomes, it becomes the anus.

Question 7

Which of the following is a real-world example of the importance of Hox genes in animal evolution?

Accepted Answer

The diversification of animal body plans during the Cambrian explosion.

Question 8

Which of the following is NOT a function of collagen in animals?

Accepted Answer

It forms the primary component of animal cell walls.

Question 9

At what stage of development can you first distinguish between diploblastic and triploblastic embryos?

Accepted Answer

Gastrulation

Question 10

Which of the following clades includes animals that undergo ecdysis (molting of an exoskeleton)?

Accepted Answer

Ecdysozoa

Question 11

Which of the following is a correct statement about the evolutionary history of animals?

Accepted Answer

The Cambrian explosion led to a dramatic increase in animal diversity and the appearance of most major animal phyla.

Question 12

Which of the following is true about the fate of the blastopore in animal development?

Accepted Answer

In deuterostomes, the blastopore becomes the anus.

Question 13

Which of the following is a feature unique to animals and not found in plants or fungi?

Accepted Answer

Specialized nervous and muscle tissues

Question 14

Which of the following best explains why mammals diversified after the Cretaceous (K-T) extinction?

Accepted Answer

The extinction of large dinosaurs opened ecological niches for mammals to exploit.

Question 15

Which of the following is a correct pairing of animal clade and characteristic?

Accepted Answer

Lophotrochozoa – trochophore larva or lophophore feeding structure

Question 16

Which of the following is a real-world example of a coelomate animal?

Accepted Answer

A cat (Felis catus)

Question 17

Which of the following best describes the difference between a true coelom and a pseudocoelom?

Accepted Answer

A true coelom is completely lined with mesoderm, while a pseudocoelom is only partially lined with mesoderm.

Question 18

Which of the following is a plausible explanation for the rapid diversification of animal body plans during the Cambrian explosion?

Accepted Answer

The evolution of the Hox gene complex allowed for greater developmental flexibility.

Question 19

Which of the following statements about animal phylogeny is supported by both morphological and molecular evidence?

Accepted Answer

All animals share a single common ancestor.

Question 20

Which of the following best describes the ploidy of most animal cells during the dominant stage of their life cycle?

Accepted Answer

Diploid ($2n$)

Introduction to Animal Diversity: Structure, Evolution, and Classification

Study Guide - Practice Questions