Weeks 9-10

Question 1

Definition of fossil?

Answer 1

Organic matter in an organism that has died and has slowly been replaced by inorganic compounds

Question 2

What can a fossil tell us about past life?

Answer 2

What an organism looked like, ate, when it lived, and what kind of environment it lived in

Question 3

What are the most common types of fossils available for understanding human evolution?

Answer 3

Hard parts of an organism like teeth and bones

Question 4

Definition of relative dating techniques?

Answer 4

Methods of dating that provide us with assessments of a fossil’s age relative to other fossils

Question 5

Definition of chronometric dating techniques?

Answer 5

Methods of dating that provide a specific age of a fossil based either on an analysis of a piece of the fossil itself or analysis of the rocks surrounding the fossil

Question 6

Relative dating technique example

Answer 6

Stratigraphy- the study of the layers of the earth

Question 7

Chronometric dating technique example

Answer 7

Dendrochronology- the study of tree rings

Question 8

What is the arboreal hypothesis?

Answer 8

Because early primate ancestors were arboreal, they developed a cluster of traits, such as specializing in herbivorous foods and a leaping/clinging type of locomotion

Question 9

What is the visual adaptation hypothesis?

Answer 9

The cluster of primate traits arose as a result of the visual nature of primate insect predation. Accurate 3-D vision, grasping hands and feet, and nails rather than claws would seem to be adaptations that fit well for an active, nocturnal, arboreal insect predator

Question 10

During which geological epoch (and how many million years ago) did the first true primates appear in the fossil record?

Answer 10

Eocene epoch- 53-35 mya

Question 11

During which geological epoch (and how many million years ago) did the first anthropoid primates appear in the fossil record?

Answer 11

Oligocene period- 35-23 mya

Question 12

During which geological epoch (and how many million years ago) did the first hominoids appear in the fossil record?

Answer 12

Miocene epoch- 22-5 mya

Question 13

Why is it rarely possible to clearly identify which fossils represent direct ancestors of primates living today?

Answer 13

Each of the Eocene primate lineages exhibit all the primitive traits we would expect to find in a primate ancestor, so it is difficult to determine which one it is without more fossils to show the evolution from one of those lineages to primates today

Question 14

What are hominins?

Answer 14

Hominins are humans and all their ancestors/relatives after the split with any other ape lineage

Question 15

What shared derived traits characterize the hominins? (5)

Answer 15

1. Modifications in the pelvic girdle and lower limbs that make them capable of effective bipedal locomotion,
2. Changes in the upper arm and vertebral column indicate that weight is borne by the legs,
3. Smaller canine teeth,
4. Forward-placed foramen magnum,
5. No shearing complex

Question 16

What features of the fossils suggest that A. afarensis locomotion was different from modern human locomotion (even though both walk upright)?

Answer 16

Long arms and curved phalanges suggest it used both terrestrial and arboreal environments, walking bipedally on the ground and moving with all four limbs through the trees

Question 17

What kinds of habitats did A. afarensis live in?

Answer 17

Primarily mixed savanna and woodland environments 4-3 mya; rich in grasses, shrubs, root and tuber plants, and fruiting/nonfruiting trees; temperatures varied across the year but were never as cool as those of the temperate world today; rainfall was about 20-32 in. per year with the possibility of a dry season(s)

Question 18

What was A. afarensis diet like?

Answer 18

Fruits, leaves, nuts or grains, and a variety of tubers and roots; insects, birds’ eggs, small mammals, reptiles, scavenge remains of carnivore kills

Question 19

Is it reasonable to argue that A. afarensis is a possible tool user? Why or why not?

Answer 19

Yes. It may have used sticks and grasses to forage for insects and may have used stones to crack nuts. All hominids use tools of some sort, so it is very likely that tool use is a primitive characteristic shared by a recent common ancestor of modern primates that was an ancestor of A. afarensis as well

Question 20

What are some of the different hypotheses proposed to explain how bipedal locomotion was favored by natural selection? (7)

Answer 20

1. Beneficial for carrying objects
2. Beneficial for hunting
3. Derived from a foraging pattern favoring upright reaching
4. Beneficial for long-distance walking or running
5. Beneficial for visual surveillance
6. Beneficial in thermoregulation
7. Male provisioning & female infant carrying resulted in bipedality

Question 21

Whiten et al. argue that chimpanzees have culture. What do they mean by this?

Answer 21

Groups of chimpanzees have social traditions that are not purely biological or genetic in origin but rather reflect a set of learned and socially transmitted behaviors.

Question 22

What is the evidence for chimpanzee culture?

Answer 22

Greeting gestures, tool use patterns (using stones to crack nuts; termite fishing)

Question 23

How do you think chimpanzee culture differs from human culture?

Answer 23

Humans use complex forms of culture and language, allowing us to construct fantastical ideas and images in our minds, share them with one another, and turn them into reality

Question 24

How do you think chimpanzee culture differs from the culture of the earliest hominin stone toolmakers?

Answer 24

Chimpanzees did not create tools, but simply manipulated stones, leaves, etc. to use as tools

Question 25

What was the environment like about 2 million years ago in Africa?

Answer 25

It was a time of climate change. Temperature fluctuations and changing seasonal patterns created mixed habitats of forests, grasslands, and open woodlands

Question 26

Which species are described as “robust”? (3)

Answer 26

Paranthropus- P. aethiopicus, P. boisei, P. robustus

Question 27

Which species are described as “gracile”? (3)

Answer 27

Australopithecus- A. africanus, A. sediba, A. garhi

Question 28

What are the major characteristics of these “robust” species? (5)

Answer 28

1. Megadontia- having larger postcanine teeth (molars/premolars) than would be expected for body size;
2. Cranial adaptations for pronounced chewing stuctures;
3. Pronounced zygomatic arches (cheekbones);
4. Sagittal ridge;
5. Relatively small body

Question 29

What are likely features of the common ancestor of modern humans and when would they have lived?

Answer 29

Bipedalism and the structure of the foot/toes; 3.2 mya

Question 30

What are likely features of the common ancestor of modern apes and when would they have lived?

Answer 30

Joint mobility in the arms/shoulders; 3.2 mya

Question 31

What evidence indicates Australopithecus that walked upright? Why?

Answer 31

Similar structure of the foot/toes. Once an ape stands upright there are many things they can do with their forelimbs and hands, which is why Jablonski thinks bipedalism evolved ex) feeding, carrying, play, gesture via hands/arms

Question 32

When does Homo erectus appear in the fossil record?

Answer 32

1.8 mya

Question 33

What are the distinctive characteristics of Homo erectus that are different from Australopithecus? (3)

Answer 33

Larger body, larger brain, carnivore (catches prey)