Mammals and Hominins

Question 1

Mammals are __ that have ___ and produce ___

Answer 1

amniotes; hair; milk

Question 2

Humans are ___ that have a __ brain and ___ locomotion

Answer 2

mammals; large; bipedal

Question 3

What are the major derived characters of mammals that distinguish them from other amniotes?

Answer 3

Produce milk, have hair and a fat layer under the skin

Question 4

What does hair and a fat layer under the skin do for mammals?

Answer 4

Help the body retain heat; they are endothermic

Question 5

What does the production of milk in mammary glands do for mammals?

Answer 5

provide a balanced diet rich in fats, sugars, proteins, minerals, and vitamins for their young

Question 6

What does brain size do for mammals?

Answer 6

Capability to learn

Question 7

Describe duration of parental care for mammals.

Answer 7

Long so offspring can learn important survival skills by observing their parents

Question 8

Describe mammals teeth

Answer 8

Differentiated- variety of size and shape adapted for chewing many kinds of foods

Question 9

Mammals belong to a group of amniotes known as

Answer 9

synapsids

Question 10

By the early Cretaceous (145-100 million years ago), the three major lineages of mammals had emerged. What are these lineages?

Answer 10

Those leading to monotremes (egg-laying mammals), marsupials (mammals with a pouch), and eutherians (placental mammals).

Question 11

What are the characteristics of monotremes?

Answer 11

Found only in Australia and New Guinea; Lay eggs, have hair and produce milk but lack nipples

Question 12

What are the main ways in which marsupials and eutherians differ from monotremes?

Answer 12

Have higher metabolic rates, have nipples that provide milk, and give birth to live young

Question 13

Along with the lining of the uterus, what do the extraembryonic membranes that arise from the embryo form in marsupials and eutherians?

Answer 13

Placenta- a structure in which nutrients diffuse into the embryo from the mother’s blood

Question 14

What is a marsupium, and how does the birth of marsupials differ from the birth of eutherians?

Answer 14

a pouch where the young is held after birth; they are born very early in development and completes it embryonic development while nursing in the marsupium

Question 15

The greatest diversity of marsupials is in ____, which has not been in contact with another continent for about 65 million years.

Answer 15

Australia

Question 16

In Australia, convergent evolution has resulted in a diversity of marsupials that resemble ____ in similar ecological roles in other parts of the world.

Answer 16

eutherians

Question 17

What is convergent evolution?

Answer 17

the process whereby organisms not closely related, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

Question 18

How do eutherians differ from marsupials?

Answer 18

placentas more complex; pregnancy longer; young complete development in uterus;

Question 19

molecular evidence indicates that marsupials and eutherians are more closely related to one another than either is to

Answer 19

monotremes

Question 20

What are the major derived characters of primates?

Answer 20

hands and feet for grasping; flat nails; skin ridges on fingers; large brain and short jaw; forward looking eyes; opposable thumb

Question 21

Many derive characters of primates have to do with the structure of

Answer 21

hands and feet.

Question 22

Primates fingers and toe nails

Answer 22

flat instead of claws

Question 23

Primates grasping

Answer 23

ridges on skin to better grasp

Question 24

Primates big toe and thumb

Answer 24

opposable

Question 25

Primates brain, jaw, and shape of the face

Answer 25

Large brain, short jaw, flat look face

Question 26

Primates overlapping visual fields

Answer 26

forward looking for better depth perception

Question 27

Primates parental care and social behavior

Answer 27

well developed parental care and complex social behavior

Question 28

What are the three main groups of living primates?

Answer 28

Lemurs et al
Tarsiers
Anthropoids

Question 29

Major differences between humans and non-human anthropoids include:

Answer 29

locomotion- stand upright and are bipedal

brain size and capabilities- larger brains and are capable of language, symbolic thought, artistic expression and the manufacture and use of complex tools

Jaw bone and jaw muscle- reduced

Digestive track- shorter

expression of regulatory genes- differ in expression of 19 regulatory genes

Question 30

What are hominins?

Answer 30

20 extinct species that are more closely related to humans than to chimpanzees

Question 31

What characteristics made early hominins such as Sahalanthropus tchadensis and Ardipithicus ramidus more human-like than chimpanzee-like?

Answer 31

Reduced canine teeth, relatively flat faces, being more upright and bipedal - foramen magnum- the hole at the base of the skull is located underneath skull instead of back of the skull

Question 32

what were some of the more “primitive” characteristics of the early hominins?

Answer 32

brains remained small; they body size was small overall; had relatively large teeth and jaw that projected beyond the upper part of the face

Question 33

What’s a common misperception relating to the evolution of hominins and the evolution of chimpanzees?

Answer 33

That humans evolved from chimpanzees

Question 34

What’s a common misperception relating to the evolution of Homo sapiens?

Answer 34

that evolution of humans was a direct ladder

Question 35

Two major trends that developed during the evolution of Australopiths:

Answer 35

complete bipedalism and tool use

Question 36

Approximately 2.4 million years ago, the first members of the genus Homo appeared. Name the two

Answer 36

Homo habilis and Homo rudolfensis

Question 37

Homo habilis and Homo rudolfensis had brain volumes ___ than the the Australopiths, and they had other morphological characters, such as a ___ jaws, that more closely resembled those of modern humans.

Answer 37

larger;

shorter;

Question 38

Homo habilis and Homo rudolfensis also appear to have made abundant use of

Answer 38

tools

Question 39

Homo ____ appeared in Africa, and Homo ____ appeared in Africa then Europe, Asia, and the South Pacific around
2 million years ago.

Answer 39

ergaster;

erectus

Question 40

Relative to earlier hominins, Homo erectus was ___ – 5-6 feet in height – with ___ legs and considerably ___ brains.

Answer 40

taller;
longer;
larger

Question 41

Homo erectus was so successful, ecologically, that it was able to spread from ___ throughout Europe, Asia, and the South Pacific.

Answer 41

Africa

Question 42

The out-of-Africa hypothesis suggests that hominins left Africa and colonized the rest of the Old World in two major waves, first as Homo___ in an initial wave out of Africa about 2 million years ago, and a second time as Homo ___ about 120,000 years ago.

Answer 42

erectus;

sapiens

Question 43

What were 3 premodern hominins before homo sapiens

Answer 43

Homo erectus; homo heidelbergensis; homo neanderthalensis

Question 44

Homo heidelbergensis evolved from

Answer 44

homo erectus/ homo ergaster

Question 45

Homo heidelbergensis populations migrated to __ and beyond while other populations remained in__

Answer 45

Europe; Africa

Question 46

that all modern humans are descended from premodern humans (______) in Africa alone.

Answer 46

H. erectus/H. ergaster

Question 47

___ ___ suggests gradual divergence of the premodern Homo species in their various locations in Africa, Europe, and Asia, with Homo sapiens arising in Africa around 195,000 years ago.

Answer 47

Fossil evidence

Question 48

Homo neanderthalensis evolved from

Answer 48

homo heidelbergensis

Question 49

Neanderthals were ____, ___, ____, and had a more pronounced __ ridge, but they shared many social and cultural characteristics with modern humans.

Answer 49

heavier, stronger, stockier; brow

Question 50

Homo sapiens evolved from

Answer 50

Homo heidelbergensis

Question 51

Explain the flow of evolution of humans and places it happened

Answer 51

H. ergaster/erectus (africa)-> H. erectus (europe) and H. heidelbergensis (africa)

H. heidelbergensis (africa)–> H. heidelbergensis (europe) and H. Sapiens Africa

H. heidelbergensis (europe)–> H. neanderthalensis Europe

H. Sapiens (Africa)–> H. sapiens (Europe)