(Q017) Your classmate, whose part-time job entails reorganizing the paleoanthropology lab on campus, asks you to take a look at a skeleton that she thinks is that of a primate. After noting the absence of a postorbital bar, nails, and an opposable thumb, what would be a valid statement to make?

Question

BlackTom AI · Accepted Answer

We begin by restating the scenario and evaluating what the observed features imply about the specimen.
Option 1: 'She should label this skeleton a plesiadapiform rather than a primate.' The absence of a postorbital bar, nails instead of claws, and a non-opposable thumb are traits more consistent with plesiadapiforms, which are stem primates and not true crown primates. This statement aligns with paleoanthropological understanding that some early skeletal forms resemble primates superficially but lack key primate features. Thus this option correctly identifies that the specimen is not a typical primate.
Option 2: 'There is no way that the skull and the hands are from the same animal.' This claim introduces an unnecessary and unfounded doubt about taphonomic or labeling possibilities. In a classroom or lab setting, there is no evidence provided that would force a conclusion that the skull and hands cannot belong to the same individual, so this is an unwarranted assertion without supporting data.
Option 3: 'The skull is probably that of an Eocene euprimate.' Euprimates are true primates that typically exhibit derived features like a postorbital bar and other primate dental and skeletal traits. The explicit note of an absent postorbital bar contradicts the characterization as an euprimate, making this option inconsistent with the observed anatomy.
Option 4: 'The skeleton is that of an Old World monkey.' Old World monkeys are crown primates and would generally possess a postorbital bar, nails, and an opposable thumb. The described absence of these primate-specific features makes this option incompatible with what is known of Old World monkeys, so it is incorrect given the evidence.
In summary, option 1 coherently integrates the diagnostic traits—absence of a postorbital bar, nails, and non-opposable thumb—with the concept of plesiadapiforms as stem primates, while the other options rely on interpretations that conflict with the observed morphology or rely on incorrect assumptions about skull–limb correspondence or primate classification.

类似问题

82. One of the most obvious, visible, physical differences between apes and monkeys is that

Is the following statement true or false? In the products of methylation-hydrolysis, every -OH group corresponds to the position of a glycosidic bond in the starting polysaccharide.

Which of the follwoing structures represents amylopectin?

Which of the following is true about an aldopentose?I. It is a monosaccharide.II. It contains a CHO groupIII. It is a disaccharide.IV. It is an oligosaccharide.

For stock A, we have 𝛽 𝑖 = 0.70. Suppose the expected market risk premium next year is 9% and the risk-free rate is 3%. What is the expected return of this stock based on the CAPM? (Please answer in % and round to 2 decimal places. If the answer is 8.057%, then in the box, write 8.06)

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单