Question 1

Which of the following traits differentiates animals from plants and fungi?

Accepted Answer

Animals contain collagen, a protein not found in plants or fungi, which is a key differentiator.

Question 2

An adult animal that possesses bilateral symmetry is most certainly also

Accepted Answer

Bilateral symmetry is a characteristic of animals that have gone through bilateral symmetry as a developmental process in which they have three embryonic tissue layers (ectoderm, mesoderm, and endoderm), hence they are triploblastic. Being a deuterostome or eucoelomate or highly cephalized is not a certain characteristic of having bilateral symmetry.

Question 3

Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that only animals derive their nutrition by

Accepted Answer

Animals ingest their food, meaning they take in solid or liquid food into their bodies orally. Fungi, on the other hand, absorb nutrients from the environment, such as dead or decaying matter, through their cell walls. Option A is incorrect as not all animals prey on other animals for nutrition. Option C is incorrect as many animals consume dead prey, such as scavengers. Option D is incorrect as both animals and fungi use enzymes to digest their food.

Question 4

What is the correct sequence (from most ancient to most recent)of milestones in the evolution of animals?

Accepted Answer

Choanoflagellates are the closest living relatives of animals, and they diverged from the animal lineage about 700 million years ago. The Ediacaran biota were a group of soft-bodied animals that lived during the Ediacaran period, which lasted from about 635 million years ago to 541 million years ago. The Cambrian explosion was a period of rapid diversification of animal life that began about 541 million years ago. The successful invasion of land by animals occurred about 475 million years ago. The origin of flight occurred about 200 million years ago.

Question 5

In individual insects of some species, whole chromosomes that carry larval genes are eliminated from the genomes of somatic cells at the time of metamorphosis. A consequence of this occurrence is that

Accepted Answer

Cloning a larva from the somatic cells of an adult insect, in species where whole chromosomes carrying larval genes are eliminated during metamorphosis, would be impossible because the necessary genetic information for larval development is no longer present in the somatic cells of the adult.

Question 6

Soon after the coelom begins to form, a researcher injects a dye into the coelom of a deuterostome embryo. Initially, the dye should be able to flow directly into the

Accepted Answer

In deuterostome development, the coelom forms from outpocketings of the archenteron. Therefore, the dye injected into the coelom should flow into the archenteron.

Question 7

Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?

Accepted Answer

The Ediacaran fauna is known for lacking hard parts, so finding evidence of such structures would be highly unexpected.

Question 8

The larvae of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following most directly favours the evolution of the latter, more radical, kind of metamorphosis?

Accepted Answer

Changes in the homeobox genes governing early development can lead to more drastic changes in the morphology of the larvae and adults. This can allow for the evolution of larvae that look completely different from adults and occupy different ecological niches.

Question 9

Which of the following is (are)unique to animals?

Accepted Answer

Nervous conduction and muscular movement are unique to animals and are not found in other kingdoms. Choice A is incorrect because cells with mitochondria are found in both animals and plants. Choice B is incorrect because chitin is found in fungi and some arthropods. Choice D is incorrect because many fungi and some protists are also heterotrophic.

Question 10

Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that

Accepted Answer

The answer of Arthropods invaded land about 100 million years...

Question 11

Fossil evidence indicates that the following events occurred in what sequence, from earliest to most recent? 1. Protostomes invade terrestrial environments.
2. Cambrian explosion occurs.
3. Deuterostomes invade terrestrial environments.
4. Vertebrates become top predators in the seas.

Accepted Answer

The Cambrian explosion (2) occurred before the rise of vertebrates as top predators in the seas (4) and before the invasion of terrestrial environments by deuterostomes (3) and protostomes (1). The correct sequence is 2 → 4 → 1 → 3. Choice C is the only one that follows this order.

Question 12

The Hox genes came to regulate each of the following in what sequence, from earliest to most recent? 1. identity and position of paired appendages in protostome embryos
2. anterior-posterior orientation of segments in protostome embryos
3. positioning of tentacles in cnidarians
4. anterior-posterior orientation in vertebrate embryos

Accepted Answer

The Hox genes first regulated the positioning of tentacles in cnidarians, an early and fundamental role in the development of body plans. They then evolved to determine the anterior-posterior orientation of segments in protostome embryos, followed by specifying the identity and position of paired appendages in these embryos. Finally, they took on the role of determining the anterior-posterior orientation in vertebrate embryos, reflecting their expanding role in the development of increasingly complex organisms.

Question 13

The last common ancestor of all animals was probably a

Accepted Answer

The last common ancestor of all animals was likely a flagellated protist, as it is believed that animals evolved from single-celled protists with flagella that were able to move and ingest food. Other options such as unicellular chytrids, yeast, multicellular algae, and fungi are unlikely to be the last common ancestor of all animals as they are not closely related to animals and have distinct differences in their cellular structure and mode of nutrition.

Question 14

Whatever its ultimate cause(s), the Cambrian explosion is a prime example of

Accepted Answer

The Cambrian explosion refers to a short period of time where there was an explosive diversification of life forms during the Cambrian period. This is a clear example of adaptive radiation, where a single ancestral species gives rise to many different species in a relatively short time. The other options, mass extinction and evolutionary stasis, do not accurately describe the Cambrian explosion.

Question 15

When you consider the evolutionary history of animals, what are some plausible explanations for the diversification and extinction of some animal species?

Accepted Answer

Both A and B are plausible explanations for the diversification and extinction of animal species. New adaptations can lead to new predator-prey interactions and changes in form and function, while certain animals may adapt better to environmental changes, leading to divergence in populations and potential extinction of certain species.

Question 16

What is the probable sequence in which the following clades of animals originated, from earliest to most recent? 1. tetrapods
2. vertebrates
3. deuterostomes
4. amniotes
5. bilaterians

Accepted Answer

The correct sequence from earliest to most recent based on evolutionary history is: Bilaterians (the earliest animals with bilateral symmetry), Deuterostomes (a group within the bilaterians that includes vertebrates, echinoderms, and others), Vertebrates (animals with backbones), Tetrapods (vertebrates with four limbs), and Amniotes (tetrapods with an amniotic egg). This sequence reflects the broad pattern of animal evolution from simple to more complex body plans and adaptations.

Question 17

What do animals as diverse as corals and monkeys have in common?

Accepted Answer

Both corals and monkeys have Hox genes, which are responsible for determining the basic body plan and segmentation in all animals with bilateral symmetry.

Question 18

Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships?

Accepted Answer

The rise of predator-prey relationships during the Cambrian explosion is most directly linked to the increased incidence of hard parts in the fossil record. Organisms developed hard parts, such as shells and exoskeletons, as protective mechanisms against predation, marking a significant evolutionary response to the new predatory pressures of the time.

Question 19

A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes is absolutely conserved, which of the following would be the best choice on which to base the phylogeny?

Accepted Answer

The answer of A researcher is trying to construct a...

Question 20

Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion?

Accepted Answer

Gene duplication could have provided a source of new genetic material for evolutionary innovation during the Cambrian explosion, allowing for the diversification of life forms seen during this period.

Quiz 32: An Overview of Animal Diversity