Exam 34: The Origin and Evolution of Vertebrates

What is believed to be the most significant result of the evolution of the amniotic egg?

Guppies are a common aquarium fish. They have internal fertilisation, and females give birth to young that can swim immediately. Which of the following statements is correct?

A trend first observed in the evolution of the earliest tetrapods was ________.

Arrange the following taxonomic terms in order from most inclusive (most general) to least inclusive (most specific).

Vertebrates and tunicates share

Brown et al. and Morwood et al. reported in 2004 that they had found skeletal remains of a previously unknown type of hominin, now dubbed Homo floresiensis, on the Indonesian island of Flores. These hominins were small (approximately 1 metre tall) with small braincases (approximately 380 cubic centimetres) as compared with other hominins. The remains of H. floresiensis were found alongside handmade stone tools and the remains of dwarf elephants that also inhabited the island, suggesting that H. floresiensis was able both to make tools and to coordinate the hunting of animals much larger than itself. H. floresiensis is estimated to have lived at the site where the remains were found from at least 38,000 years ago to 18,000 years ago. It is speculated that H. floresiensis and H. sapiens may have lived on Flores concurrently. Suppose researchers obtained mitochondrial DNA samples from the H. floresiensis remains, amplified a 1,000-base-pair sequence via PCR, and compared it to that of several currently living H. sapiens native to Indonesia, North Africa, and North America. Also suppose H. floresiensis were found to differ from the average Indonesian H. sapiens in 28 base pairs, from the average North African H. sapiens in 51 base pairs, and from the average North American H. sapiens in 53 base pairs, while two randomly selected H. sapiens differed from each other in an average of 21 base pairs. What would you surmise from these data?

On the back of your skull you can feel a small bump, below which is an opening where the spinal cord enters the skull. The location of this opening toward the bottom of the skull is significant in evolutionary biology for what reason?

Which of the following could be considered the most recent common ancestor of living tetrapods?

Which of the following characteristics evolved independently in mammals and birds?

With which of the following statements would a biologist be most inclined to agree?

Which of these would a palaeontologist most likely do to determine if a fossil represents a reptile or a mammal?

Terry catches a ray-finned fish from the ocean and notices that attached to its flank is an equally long, snakelike organism. The attached organism has no external segmentation, no scales, a round mouth surrounded by a sucker, and two small eyes. Terry concludes it is a hagfish. Terry saved some of the tooth-like objects within the hagfish's round mouth to analyse their composition in his mentor's biochemistry research lab. Terry will find that they are composed of the same protein found in tetrapod ________.

Jaws first occurred in which extant group of fishes?

Vertebrates and tunicates share ________.

Which of the following statements about the geographic distribution of marsupials is accurate?

Why do skates and rays have flattened bodies, while sharks are torpedo-shaped?

As hominins diverged from other primates, which of the following appeared first?

Which extant chordates are postulated to be most like the earliest chordates in appearance?

At one time, Chondrichthyes were thought to have split off from other vertebrates before the evolution of bone. Now we have concluded that the Chondrichthyes split off after the evolution of bone had started. This change demonstrates ________.

Due to its system of air sacs connected to the lungs, the respiratory system of birds is arguably the most effective respiratory system of all air-breathers. Upon inhalation, air first flows into posterior air sacs, then into the lungs, and then into anterior air sacs on the way to being exhaled. Thus, there is one-way flow of air through the lungs, along thousands of tubules called parabronchi. -If the inner lining of the air sacs is neither thin nor highly vascularised, then what can be inferred about the air sacs?