Deck 11: Animal Diversifi Cation

Question 1

The two most important evolutionary innovations in vertebrates, which resulted in their eventual domination among the large animals, were:

A) air-breathing lungs and a more efficient heart.
B) opposable thumbs.
C) jaws and amniotic eggs.
D) the ability to walk or fly.
E) air-breathing lungs and endothermy.

Answer 1

All vertebrates have a backbone and a head at one end which has a skull to hold the brain and sensory organs. The earliest vertebrates were lampreys which are jawless parasites. It wasn't until jawed, finned fish evolved that these vertebrates were able to chase down their prey and hold on to it with their jaws. Jaws also allowed these fish to rip apart larger prey and chew it before swallowing it. This led to a wide diversification in vertebrates.
The next major changes in vertebrates came when they made the transition onto land. Some of the changes were mere adaptations of existing body structures. Swim bladders became lungs. Lobed fins became limbs; and the backbone became notched to support the weight on land. However, a major change had to occur to vertebrate eggs. These were normally laid in the water and fertilized externally. The eggs would dry out on land. This led to the evolution of amniotic eggs which have a shell and water-tight membrane to protect the embryo inside.
The correct Answerto this question is c) jaws and amniotic eggs.
Adaptations such as lungs that can breathe air, a heart that is more efficient, walking, flying, and the ability to regulate internal temperature (endothermy) were all important improvements in the evolution of vertebrates. However, these were not the critical new adaptations that drove these animals to diversity rapidly. Therefore, the answers to a), b), d) and e).

Question 2

Which of these animals is a tetrapod that does not produce amniotic eggs?

A) salamander
B) human
C) monkey
D) elephant
E) python

Answer 2

Tetrapods are animals that have four feet. Technically, even though some do not appear to have four feet, all vertebrates that live on land on tetrapods. A snake, for example, has the bone remnants of limbs.
Terrestrial vertebrates are classified as either non-amniotes or amniotes. Non-amniotes, such as amphibians, are those that reproduce in water and do not have amniotic eggs. Amniotes, such as mammals and reptiles, produce amniotic eggs.
The correct Answerto this question is a) salamander. A salamander is an amphibian, which does not produce amniotic eggs because it reproduces in the water.
Humans are mammals which produce amniotic eggs. The Answerto b) is incorrect.
Monkeys are mammals which produce amniotic eggs. The Answerto c) is incorrect.
Elephants are mammals which produce amniotic eggs. The Answerto d) is incorrect.
Pythons are reptiles which produce amniotic eggs. The Answerto e ) is incorrect.

Question 3

Why is the amniotic egg considered a key evolutionary innovation?

A) It prohibits external fertilization, thereby facilitating the evolutionary innovation of internal fertilization.
B) It has an unbreakable shell.
C) It greatly increases the likelihood of survival of the eggs in a terrestrial environment.
D) It enables eggs to float in an aquatic medium.
E) It extends the time of embryonic development.

Answer 3

Fish laid their eggs in the water and fertilized them externally. The eggs would dry out if they were laid this way on land. So, a major change had to occur to vertebrate eggs in order for vertebrates to move onto land. This led to the evolution of amniotic eggs which have a shell and water-tight membrane to protect the embryo inside from drying out. Amniotic eggs allowed vertebrates to expand their habitat and move away from water.
The correct Answerto this question is c) It greatly increases the likelihood of survival of the eggs in a terrestrial environment.
Internal fertilization would have to have evolved before amniotic eggs or the eggs would not have laid with embryos inside. The Answerto a) is incorrect.
Amniotic eggs do not have unbreakable shells, which is one of the major dangers to the developing embryo. The Answerto b) is incorrect.
Terrestrial animals do not have to lay their eggs near an aquatic medium. The Answerto d) is incorrect.
Amniotic eggs do not change the developmental time for the embryo. The Answerto e) is incorrect.

Question 4

Which came first, the chicken or the egg?

A) The chicken, because the amniotic egg did not evolve until the first chicken appeared.
B) The egg, because the amniotic egg evolved well before the first birds.
C) The chicken, because, during speciation, the adult stage always precedes the juvenile stage.
D) The egg, because the chicken is not a real species.
E) It is impossible to determine, because eggs leave no fossils.

Question 5

Which of the following is not a reptile?

A) sparrow
B) snake
C) frog
D) turtle
E) dinosaur

Question 6

Which of the following is not a characteristic of all animals?

A) They are able to move at some point in their life.
B) They get their energy by eating other organisms.
C) They are multicellular.
D) They are reproducing sexually at some point in their life cycle.
E) All of the above are characteristics of all animals.

Question 7

Marsupials and which of the following groups combine to make a monophyletic group?

A) birds
B) carnivores
C) primates 43
D) monotremes
E) placental mammals

Question 8

The lineage that first separated from the common ancestor of all animals, and retains many of those primitive features to this day, includes which of the following modern organisms?

A) the grasshopper
B) the jellyfish
C) the sponge
D) the earthworm
E) the sea turtle

Question 9

According to the fossil record, the first humans appeared approximately ______ years ago.

A) 6 million
B) 6,000
C) 190 million
D) 100,000
E) 1 million Short-Answer Questions

Question 10

Which of the following extant species is the most evolutionarily successful?

A) the house mouse (Mus domesticus)
B) the housefly (Musca domestica)
C) the Western gorilla (Gorilla gorilla)
D) Irukandji, the toxic jellyfish (Carukia barnesi )
E) All of the above species are equally successful because they are not extinct.

Question 11

The cheetah is an amazingly fast cat that hunts its prey on the African savannas, sprinting for short distances at speeds approaching 70 miles per hour. The sloth in the Amazon rain forests of South America is a very slow creature that hangs from a tree by all four limbs and eats vegetation. How can this difference-that the cheetah can sprint at high speeds, while the sloth moves almost in slow motion-be explained in evolutionary terms? What modifications might occur to the cheetah's ability to run if it were to occupy the same niche as the sloth, assuming the cheetah had no natural enemies there?

Question 12

Sponges are sessile, meaning that they:

A) reproduce asexually.
B) are parasitic and depend on their host for a constant supply of nutrients.
C) have exoskeletons that they must shed as they grow.
D) live within shells they find on the ocean floor.
E) live attached to a solid structure and do not move around.

Question 13

Explain why an ectotherm, such as a snake, requires only an occasional meal, while an endotherm, such as a mouse, requires more frequent meals to survive?

Question 14

In cnidarians, cnidocysts are primarily used for:

A) creation of water flow across the body wall.
B) formation of free-living medusas.
C) secretion of digestive enzymes.
D) prey capture and defense.
E) muscular contraction during movement.

Question 15

A caring pet owner brings her boa constrictor to the veterinarian because it has been more sluggish than normal and seems to be ill. The veterinarian is concerned when she sees that the owner has placed a thick sweater, specially knitted, on the snake. Why might the sweater worry the veterinarian?

Question 16

The mollusk's mantle is used primarily for:

A) feeding.
B) gas exchange.
C) producing the shell.
D) excretion.
E) reproduction.

Question 17

You have a friend who confuses a terrestrial slug with a segmented worm (annelid). Describe some of the characteristics of the slug that you could point out to him that are not found in any annelids.

Question 18

Which of the following insect groups has the most species currently named by scientists?

A) bees, wasps, and ants
B) beetles
C) grasshoppers and crickets
D) flies
E) butterflies and moths

Question 19

Which is the only animal phylum to have more than a million described species?

A) chordates
B) arthropods
C) flatworms
D) nematodes
E) mollusks

Question 20

The phylum Arthropoda includes all of the following kinds of animals except:

A) snails.
B) crabs.
C) crayfish.
D) butterflies.
E) scorpions.

Question 21

Which of the following traits is unique to arthropods?

A) a ventral nerve cord
B) an exoskeleton
C) segmentation
D) a large ratio of brain size to body size
E) wheeled appendages

Question 22

Which of the following are chordates?

A) fishes
B) humans
C) frogs
D) All of the above are chordates.
E) Only a) and c) are chordates.