Q20. A primitive trait is a trait which is similar in both t…
Q20. A primitive trait is a trait which is similar in both the ancestor and the descendant. This is the opposite of a _________ trait which is a trait that has newly emerged in the descendant and is not found in the ancestor. The grasping hands with nails found in Eocene primates of 55 million years ago represent a ______ trait when compared to the non-grasping hands with claws found in early mammals of 200 million years ago (Mya). [Note: The same word is used for both blanks] Q21. All primates have prehensile hands with long fingers, an opposable thumb and _________ (instead of claws) on their digits. All primates have touch receptors in their fingertips for getting information about the world. Q22. All primates have eyes facing in the forward plane with some degree of bony eye protection. Supported by visual information sent by each eye to each hemisphere of the brain, this provides the basis for ___________ vision (which allows primates to be good at judging distance). Q23. Matt Cartmill proposed that the earliest primates used their grasping hands and stereoscopic vision to harvest and feed on insects. All contemporary primates (including humans) still use well-developed _________ coordination to grasp and bring food to the mouth. In contrast, most mammals bring their mouth to the food (e.g. dogs, cats, horses, porpoises, etc.). Q24. All hominoids show adaptations for under branch ___________ including long muscular arms, a shoulder joint with 360 degree rotation, fully extendable elbow, 180 degree forearm rotation and an increase is side-to-side wrist motion. Humans are hominoids and have all of these adaptations. Q25. Brain tissue is energetically expensive. In the motor cortex of the human brain, the large amount of cortical tissue devoted to controlling ________movements suggests that this hand digit is very critical to the human way of life. Q26. Humans are unusual among anthropoid primates in having small ______ teeth. All other anthropoids have a ________ cutting complex but humans do not. Instead they have strong pterygoid muscles and the ability to move the jaw sideways against the upper dentition (allowing for rotary chewing). [Note that the same term is used in both blanks]. Q27. The fossil record for life on earth begins about 3.5 billion years ago during the geological interval known as the _______ Eon. Q28. The emergence of vertebrates (and the successive evolution of bony fish, amphibians and early reptiles) can be seen in the fossil record of the Paleozoic Era. This time interval ends with the largest ___________event in the history of life on this earth. Q29. Mammals with four different kinds of teeth for food processing make their first appearance about 200 million years ago in the Mesozoic Era. However it is not until the __________ Era (which begins 65 million years ago) that mammals radiate into the 28 distinctively different orders of modern mammals that are found today. Q30. The widely distributed Adapiformes (including Smilodectes) is an Eocene taxon of early ______ which have grasping hands and forward-facing eyes. This suggests that eye-hand coordination was as important in this 55 million-year-old taxon as it is among the contemporary members of the order.
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