32. Vertebrates

Primates and Homonids

Hominids

No. Ardipithecus ramidus had a small brain.

No. Australopithecus afarensis had a small brain.

No. Homo erectus had an enlarged brain, but Homo habilis appeared first.

No. The Neanderthals had enlarged brains, but Homo habilis appeared first.

Consider which of these species is the first to be definitively associated with tool use.

What was the earliest hominin to have an enlarged brain (relative to body size)?

 No. Humans do not have opposable big toes. 

 No. Culture is not well documented in all primates, and it has been reported in nonprimate mammals. 

 No. Only hominids, including modern humans, are bipedal. 

 a thumb that is relatively mobile and separate from the fingers 

Without this characteristic you would find it difficult to do many of the tasks you take for granted.

Humans and lorises share many traits that probably evolved in our early primate ancestors; one such trait is __________.

In the primate phylogenetic tree below, fill in groups (a)–(e). Of the groups, which are anthropoids and which are apes? 
a. 
b. 
c. 
d. 
e. <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/99765530cede9a12-1677717717129.jpg" style="width: 300px;">

Anthropologists are interested in locating areas in Africa where fossils 4–8 million years old might be found. Why?

As hominins diverged from other primates, which of the following appeared first?
a. reduced jawbones
b. an enlarged brain
c. the making of stone tools
d. bipedal locomotion

Characteristics of Primates

Fossils suggest that the first major trait distinguishing hominins from other primates was
a. a larger brain.
b. erect posture.
c. forward-facing eyes with depth perception.
d. tool making.

This trait is seen in some Old World monkeys too.

All species of New World monkeys are __________.

Short Video: Chimp Cracking a Nut

Homonids

The earliest members of the genus Homo
a. had a larger brain compared to other hominins.
b. probably hunted dinosaurs.
c. lived about 4 million years ago.
d. were the first hominins to be bipedal.

Which of the following correctly lists possible ancestors of humans from the oldest to the most recent?
a. Homo erectus, Australopithecus, Homo habilis
b. Australopithecus, Homo habilis, Homo erectus
c. Australopithecus, Homo erectus, Homo habilis
d. Homo ergaster, Homo erectus, Homo neanderthalensis

Draw a phylogeny of major populations of modern humans that would reject the out-of-Africa hypothesis.

Humans possess which of the following traits? Select True or False for each trait.
T/F triploblasty
T/F parthenogenesis
T/F viviparity
T/F metamorphosis

 No. Some nonhominin apes (e.g., chimpanzees) use tools. 

 An enlarged brain (relative to body size) 

 No. Early hominins (e.g., australopithecines) had small brains. 

 No. Neither apes nor hominins have tails. 

Consider how you differ from other apes.

Which of the following traits distinguishes hominins from other apes?

Primates- What is a Primate?

SCIENTIFIC THINKING By measuring the fossil remains of Homo floresiensis, scientists have estimated its weight to be around 32.5 kg and its brain volume to be roughly 420 cm3. Plot these values on the graph in Figure 19.13A. Which hominin has the most similar relationship of brain volume to body mass? Does this information support the hypothesis that H. floresiensis is a dwarf form of H. erectus, or an alternative hypothesis? Explain. <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/059a6fdb83b5f491-1677717860087.jpg" style="width: 300px;">

Primate Classification

Hominin, Hominids, Hominoid Difference

Primate Traits for Classification

Primates

Summarize the hypotheses that explain variation in human skin color as adaptations to variation in UV radiation.

Homo neanderthalensis was ancestral to Homo sapiens

 No. All living humans are more closely related to each other than to Neanderthals. 

Homo sapiens evolved from H. erectus in several parts of the world

No. Most researchers agree that Homo sapiens evolved in Africa.

Homo sapiens has many common ancestors

 No. Most evidence suggests that human evolution followed a fairly streamlined course. 

Homo sapiens settled in the New World approximately 75,000 years ago

 No. Although this is a subject of much debate, the oldest generally accepted evidence puts that date at 15,000 years ago. 

Modern humans are a monophyletic group.

Analysis of DNA from a variety of sources has led most researchers to agree that __________.

Short Video: Gibbons Brachiating

One of the misconceptions about human evolution is expressed in the question “If chimpanzees were our ancestors, then why do chimpanzees still exist?” Use Figure 19.10A to explain the answer. <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/c6bba172a98eb718-1677717815393.jpg" style="width: 300px;">

 Old World monkeys and New World monkeys 

 No. Although monkeys and apes are anthropoids, monkeys are not apes. 

 No. Chimpanzees are considered apes, but monkeys are not. 

 gibbons, orangutans, gorillas, chimpanzees, and bonobos 

All but one group of apes are larger than monkeys.

Included among the extant groups of apes are __________.

 No. Modern humans do not have prominent brow ridges. 

 No. An upright posture evolved earlier than did a large brain. 

 No. The evolution of forward-looking eyes preceded the evolution of an upright posture. 

 None of the listed responses is correct. 

 No. One of the other choices is correct. 

Large brains followed the evolution of many other human traits.

__________ arose very early in hominid evolution; __________ evolved more recently.

Great Transitions: The Origin of Humans — HHMI BioInteractive Video

Draw a phylogeny of major populations of modern humans that would reject the out-of-Africa hypothesis.<img src="https://lightcat-files.s3.amazonaws.com/problem_images/36a2c6a0ac5d7fe2-Homo.jpg" alt="" />

hominid evolution

Sahelanthropus, Ardipithecus, Homo, Australopithecus

No. Australopithecus is not the most recent.

Australopithecus, Ardipithecus, Sahelanthropus, Homo

No. Sahelanthropus is the oldest.

Homo, Sahelanthropus, Ardipithecus, Australopithecus

Homo, Ardipithecus, Australopithecus, Sahelanthropus

Sahelanthropus, Ardipithecus, Australopithecus, Homo

Your genus is represented here.

Which of the following correctly lists probable ancestors of modern humans from the earliest to the most recent?

Which of these is not a member of the anthropoids?
a. chimpanzee
b. tarsier
c. human
d. New World monkey

Hominoids, Hominids and Hominidae

Early Humans...in five minutes or less

What adaptations inherited from our primate ancestors enable humans to make and use tools?

HHMI BioInteractive: The Origin of Humans

Explain some of the reasons why the human species has been able to expand in number and distribution to a greater extent than most other animals.

Genetic diversity in living human populations is highest in Africa and decreases as a function of distance traveled by the human migration that left Africa many millennia ago. Draw a graph to show this trend. (Hint: What is the independent variable? What is the dependent variable? What kind of graph is appropriate for this kind of data? Add a label where you would expect to find a data point for the Yanomamö tribe of the Amazon rain forest in South America. Why is it important to use indigenous people for this study? <IMAGE>

Studies of DNA support which of the following?
a. Members of the group called australopiths were the first to migrate from Africa.
b. Homo sapiens originated in Africa.
c. Sahelanthropus was the earliest hominin.
d. Chimpanzees are more similar to gorillas and orangutans than to humans.

Most species of hominins are known only from Africa. Which species have been found in other parts of the world as well?
a. early Homo—H. habilis and H. ergaster
b. H. erectus, H. neanderthalensis, and H. floresiensis
c. gracile australopithecines
d. robust australopithecines

Genetic diversity in living human populations is highest in Africa and decreases as a function of distance traveled by the human migration that left Africa many millennia ago. Draw a graph to show this trend. (Hint: What is the independent variable? What is the dependent variable? What kind of graph is appropriate for this kind of data? Add a label where you would expect to find a data point for the Yanomamö tribe of the Amazon rain forest in South America. Why is it important to use indigenous people for this study? <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/be0b441f28eb246c-1677300227905.jpg" style="width: 300px;">

 No. Primates have flat nails, not the claws typical of other mammals. 

 No. Mammals other than primates have single births. 

 eutherian reproduction, opposable thumbs, and good depth perception 

 No. Many mammals other than primates have eutherian reproduction. 

 long tails used for balance, mammary glands, and opposable thumbs 

 No. Other mammals also have long tails used for balance, and some primates (such as humans) lack tails. 

 opposable thumbs, nails, and good depth perception 

Consider that the earliest primates were probably tree dwellers.

Primates are distinguished from other mammals by __________.

Lecture 82 The First Primates

Learn the toughest concepts covered in Biology1&2 with step-by-step video tutorials and practice problems by world-class tutors 