Life sciences Grade 12 CAPS - PowerPoint Presentation

Slide1

Life sciences Grade 12 CAPSstructured, clear, practical - Helping teachers unlock the power of NCS

KNOWLEDGE AREA: Diversity, Change and ContinuityTOPIC 4.2:Human Evolution

Evidence of Common Ancestors for Living Hominids including Humans

Slide2

Summary of presentation

Slide3

Phylogenetic tree to show the family HominidaeBefore we look at the

phylogenetic tree we must first study the classification of humans.Humans are found in the

class mammalia.They belong to the order Primates

and thenThey are found in the sub-order AnthropoideaThis sub-order is made up of

2 families.These are family Hylobatidae, and family Hominidae.Humans fall into the family Hominidae.

Slide4

Phylogenetic tree to show the family HominidaeThen

genus HomoFinally species Homo sapiens This is all shown in the picture alongside.Here we often come across the terms hominid and

hominin.Lets look at these 2 terms.

Classification of Humans

Slide5

Phylogenetic tree to show the family HominidaeHominid

refers to the group which contains modern humans, chimpanzees, gorillas and orangutans.It also

includes all their immediate ancestors.In other words

all the organisms found in the family Hominidae.Hominin refers to

modern humans and all the extinct human species.It also includes all our immediate ancestors.Now will look at how the humans are similar and different to the African apes.

Slide6

Phylogenetic tree to show the family HominidaeThe African apes

include the gorillas, chimpanzee and bonobos.Now lets look at the phylogenetic tree.

Chimpanzee

Bonobos

Slide7

Terminology:

TERM:

Hominid

DEFINITION:

Hominid refers to the group which includes modern humans, chimpanzees, gorillas and orangutans.USE IN SENTENCE:Humans belong to the family Hominidae

Slide8

terminology

TERM:Hominin

DEFINITION:

Hominin refers to modern humans and all the extinct human speciesUSE IN SENTENCE:Australopithecus and Paranthropus

belong to the group Hominin

Slide9

Phylogenetic tree to show the family HominidaeThe phylogenetic trees on the next 2 slides gives some information on human evolution.

We will use both these trees to trace human evolution from about 6 million years ago.

Slide10

Phylogenetic tree to show the family Hominidae

Slide11

Phylogenetic tree to show the family Hominidae

Slide12

Phylogenetic tree to show the family HominidaeBetween

6 to 7 mya the first bipedal primates appeared.These organisms had the following features:Small brain size

Foramen magnum had a forward position.Small canine teeth

Then about 4mya Australopithecus appeared.They had

features of both primitive apes and modern humans.They had the head of primitive apes and from the neck down they looked like the modern humans.Therefore they are often called ape-men.

Slide13

Phylogenetic tree to show the family HominidaeThe features shared with primitive apes were

…Protruding jawsHeavy brow ridgesSlopping faces

Small brain.

Australopithecus

Slide14

Phylogenetic tree to show the family HominidaeA

new genus appeared between 4.32 and 4.51 million years ago.This was the Ardipithecus.This

genus was made up of 2 species.

They were A. ramidus and

A. kadabbaA. kadabba lived about 5.6 mya.

A.

ramidus

Slide15

Phylogenetic tree to show the family HominidaeA. ramidus

had the following features…A small brainA pointed face and poorly developed chinA grasping big toe for swinging from branch to branch of trees.

It was also adapted for bipedalism.

Then about 2 mya the australopithecines gave rise to Homo habilis (the handy man)

H. habilis was referred to as the handy man because fossil evidence showed that they used tools.H. habilis was first of the early humans.H. habilis was different from the australopithecines in the following way…

Slide16

Phylogenetic tree to show the family HominidaeLess pronounced brow ridges

More human like teethA flatter faceA more rounded head

A brain capacity of 600 to 750ml.

homo habilis

Slide17

Phylogenetic tree to show the family HominidaeIt is thought that about

1.5 mya H. habilis gave rise to Homo erectus.

H. erectus had the head of an ape

but from the neck down it looked like modern man.It was as tall as modern man

and had a larger brain size of 700 ml to 1300ml.Homo erectus

Slide18

Phylogenetic tree to show the family HominidaeThen about 150 000 to 200 000

years ago h. erectus gave rise to Homo sapiens.We will look at these in a little more detail later on.

Slide19

Lines of Evidence that Support the Idea of Common Ancestors for Living Hominid, Humans included

Two groups of the African apes share a common ancestor with humans.

These 2 groups of apes are the

chimpanzee and bonobos.We want to look at evidence that support the idea of a common ancestor.We look at 3 lines of evidence.These are …

Fossil evidenceGenetic evidenceCultural evidenceLets look at each of these in some detail.

Slide20

Lines of Evidence that Support the Idea of Common Ancestors for Living Hominid, Humans included

Fossil Evidence:From our earlier discussion we can see that many hominin fossils

have been discovered over the years.Hominin fossils belong to

at least 20 species.These fossil provide evidence for a

close evolutionary relationship between humans and the great apes.The fossils use anatomy to show this relationship.The fossils provide 2 lines of evidence.

Slide21

Lines of Evidence that Support the Idea of Common Ancestors for Living Hominid, Humans includedThese are…

Transitional fossils:This refers to the immediate fossils between a group and their ancestor. In this case the

transitional fossils have

characteristics of both the apes and humans.The great –ape characteristics are also found in the common ancestor

, butThe human characteristics occur only in the hominins.

Slide22

Lines of Evidence that Support the Idea of Common Ancestors for Living Hominid, Humans included

The Oldest fossils:These fossils have more characteristics of the great apes than the younger fossils.

These younger fossils are

more like the modern human.Over a period of time we see that the fossils become more human like than ape like

.We shall look at the similarities and differences between the great apes and humans a little later.

Slide23

Lines of Evidence that Support the Idea of Common Ancestors for Living Hominid, Humans includedGenetic Evidence:

The DNA base pairing of humans and the Great apes are

almost identical.The

human DNA sequence is most similar to the chimpanzee.

Humans and chimpanzee have 98.76% of the base pair sequence in common.Since DNA sequence is so similar it provides evidence for a close relationship between humans and chimpanzees.

Slide24

Lines of Evidence that Support the Idea of Common Ancestors for Living Hominid, Humans includedCultural Evidence

:Fragments of sticks, burned bones, stone weapons and tools etc, were used as cultural evidence for human evolution.

Chimpanzees also use tools , for example using

stones to open nuts.Young chimpanzee learn behaviour from watching their mothers

.Therefore it is believed that the common ancestor of humans and chimpanzee also used similar tools in a similar way.

Slide25

terminology:

TERM:

Transitional fossils

DEFINITION:

refers to the immediate fossils between a group and their ancestorUSE IN SENTENCE:Transitional fossils are used can be used as fossil evidence to show relationship between a group and their ancestor.

Slide26

Characteristics that Humans share with the African ApesMany of the

early mammals lived on trees.Many of the African apes are

still adapted for an arboreal life

.Humans share the following characteristics with the African apes and other primates…The upper limbsThe brain

VisionNumber of OffspringUpright posture

Slide27

Characteristics that Humans share with the African ApesThe Upper Limbs:

Primates have very long arms, which they move freely

.They are able to

move their arms freely because…The socket is

very shallow.The scapula is not attached to the vertebral column.They do not have claws, instead they have flat nails.Their

fingertips are bare

and

contain a large amount of nerve endings

.

Finally all

primates have opposable thumbs

.

Slide28

Characteristics that Humans share with the African ApesThe

long arms are used to gather fruit from the tips of tree branches.Their

bare fingertips are very sensitive

, this makes precision work possible. Therefore they are able to make and use tools.The

opposable thumbs makes the power grip and precision grip possible.Like primates humans have… opposable thumbs, flat nails instead of claws and freely moving upper limbs.

Slide29

Characteristics that Humans share with the African ApesBrain:

We find that when we compare the brain to body size, the primates have large brains compared to their body size.

This enables them to

process large amounts of information.Parts of the brain responsible for interpretation information coming from the hands

and eyes are enlarged.The olfactory organ is much reduced because primates do not depend on the sense of smell.

Slide30

Characteristics that Humans share with the African ApesVision:

Their eyes are found in the front.

They display both stereoscopic and binocular vision.

They have rods and cones to enable a more clear and colour vision.

Slide31

Characteristics that Humans share with the African ApesNumber of Offspring Produced:

Primates produce far less offspring.Parental care is

intensive.

Upright Posture:They have an upright posture, which

allows for the primates to walk on two legs.This allows for better view of the surroundings.Upper limbs are free for carrying things such as food, babies and tools.

Slide32

Terminology:

TERM:

Arboreal

DEFINTION:Refers to living in trees

USE IN SENTENCE:Chimpanzees have an arboreal life

Slide33

TERMINOLOGY:

TERM:

Stereoscopic vision

DEFINITION:Refers to see the depth and solidity of objects

USE IN SENTENCESPrimates exhibit stereoscopic vision

Slide34

Terminology:

TERM:

Binocular vision

DEFINITION:The process of looking at an object with both eyesUSE IN SENTENCE:

Humans have binocular vision

Slide35

Something for you to do:List the characteristics that humans share with the African apes.

Slide36

Solution:

Large brains compared to their body mass. Therefore a large skull.Reduced sense of smell due to a reduced olfactory center in the brainParts of the brain that process information from hands and eyes are larger.

Retina contains cones to make color vision possible.

Stereoscopic visionBinocular visionLong upper armsUpper arms – full and free movement

Slide37

Solution:Forearm can rotate because of elbow joint

No claws, nails are flatNo hair on fingertips-bare fingertipsOpposable thumbs

Upright posture.

This is a good learning tool use it to learn the similarities.

Slide38

Terminology:

TERM:Opposable thumb

DEFINITION:

The thumb is opposite the fingers USE IN SENTENCE:The opposable thumb

allows for the precision grip.

Slide39

Anatomical Differences between the African Apes and Humans

Anatomy refers to structural make up of an organism.In this section we will look at how the humans and African apes are structurally different from each other.The following anatomical differences occur between the humans and the African Apes…

Bipedalism

Brain size DentitionFlat face/Prognathism

Cranial ridgesBrow ridges

Slide40

Anatomical Differences between the African Apes and Humans There is

fossil evidence to support these anatomical differences.Now lets look at each of these in some detailBipedalism:

The African apes sit upright

and are able to walk on 2 feet.However they do this

only sometimes, while humans walk on 2 legs all the time.Animals that show bipedalism have a different arrangement of the vertebral column to the head

Slide41

Anatomical Differences between the African Apes and Humans

Therefore the position of the foramen magnum had to change.It moved from the

back of the skull to a forward position at the bottom of the skull as shown alongside.This means that in

animals that show bipedalism, the foramen magnum is in a forward position at the bottom of the skull, while

Position of Foramen Magnum

Slide42

Anatomical Differences between the African Apes and Humans The animals that show

quadrupedalism have a foramen magnum at the back of the skull.

Slide43

Anatomical Differences between the African Apes and Humans In addition

animals with bipedalism had a much wider and shorter pelvis, because the pelvic girdle had to support the weight of the body.

While quadrupeds have long, narrow pelvic girdles.

Comparison of pelvic girdle of

human and chimpanzee

Slide44

Anatomical Differences between the African Apes and Humans Finally the

spine of an organism with bipedalism is straighter than a quadrupedal

.

Comparison of the Spine

Slide45

Terminology:

TERM:

Bipedalism

DEFINITION:Refers to a type of locomotion where the animal moves on 2 hind legs in an upright position

USE IN SENTENCE:The African apes move in a bipedal fashion only sometimes.

Slide46

Anatomical Differences between the African Apes and Humans Brain Size:

Over the time the brain size of the hominin species has gradually increased.

Homo sapiens have a

brain size twice that of Homo habilis.The brain size of the first bipedal apes

was half the size of the brain of Homo habilis.The brain of the modern man is the biggest.It ranges in size from

1200ml to 1800ml

.

Slide47

Anatomical Differences between the African Apes and Humans The

advantage of the large brain size compared to their body masses over those apes that had a smaller brain compared to their body mass size is greater intelligence.But it must be noted that this

does not apply to modern humans.Since humans have a

larger brain they also have a larger skull.Dentition:Apes have

large canines that protrude.In humans the canines are much smaller and is shaped almost like an incisor.

Slide48

Anatomical Differences between the African Apes and Humans The

incisors in humans do not stick out, while in chimpanzees they stick out spatulas or spoons.The dental formula a of humans is 2.1.2.3

2.1.2.3The dental formula of the oldest primates are

2.1.3.32.1.3.3The

apes have a u-shaped jaw with parallel sides and the front is slightly rounded.The incisors are found at the front and canines

,

premolars and molars are on the side

.

Humans

have a

gently curved jaw

.

Slide49

Terminology:

TERM:

Dentition

DEFINITION:Refers to the development of teeth and the way they are arranged in the mouth

USE IN SENTENCE:The oldest primates and humans have different dentition.

Slide50

Anatomical Differences between the African Apes and Humans A flat face / Prognathism:

Modern humans have a flat face.The following features ensures that humans have a flat face…

The foreheads of

modern humans do not slope backwards while the forehead of the ape men slope backwards.

Humans have a well developed chin on their lower jaws. Human chins are square shaped, this is thought to be an adaptation for speech. Chimpanzees have rounded chins

.

Slide51

Anatomical Differences between the African Apes and Humans The

bones of the nose and jaws stick out in the ape man in other words ape men were prognathous. Modern humans are

not prognathous, this means that the

bones of the nose and jaws do not stick out.Humans have shorter palates than apes.The chimpanzee have

a parallel-sided palates.While the palates of the Australopithecus have a U-shaped palate.

Slide52

Terminology:

TERM:Prognathous

DEFINITON:

Refers to the projection of the jaws and nose that leads to a pointed face.USE IN SENTENCE:

The African apes are prognathous.

Slide53

Anatomical Differences between the African Apes and Humans Cranial ridges:

Cranial ridges are found at the back of the skull.

Cranial ridges of humans do not protrude as those of

ape men.Brow ridges:The

ape men have larger brow ridges than humans.In most cases the brow ridges in humans are absent.

Slide54

Something for you to do:

Slide55

Solution:3.2.1 A – Gorilla

B – Modern human3.2.2

Gorilla

HumanCanines well developed/form fangs

Canines not well developedSloping faceFlat faceBrow-ridge well developedBrow-ridge less developedProportionally smaller cranium/brain

Proportionally large cranium/brain

Slide56

Solution:

GorillaHuman

Proportionally wider cheek bone

Proportionally narrower cheek bone

Foramen magnum towards the back of the skullForamen magnum towards the centre of the skull/more forward

Chin not well developed

Chin well developed

No pronounced forehead

pronounced forehead

Slide57

Solution:3.2.3 B

3.2.4 Allows total awareness of the environment in sensing danger/looking for food - Enables hands to be free to use implements /carry objects or offspring/throw/protect - Exposes a large surface area for thermo- regulation /lose body heat to surroundings in hot conditions/reduce overheating therefore reduce need for water

- Display of male/female sex organs as part of courtship behaviour

Slide58

Something extra:

You can use these answers to enhance or even make your studying easier.You can use the table to learn the differences between the African Apes and modern human.

The answer to question 3.2.4 can be used to learn the advantages of bipedalism

Slide59

Something to do:

Slide60

Solution:3.1.1 (a) Pan troglodytes/chimpanzee/C

(b) Homo erectus/A (c) Homo sapiens /BOR (a)

Homo erectus/A (b) Pan troglodytes/chimpanzee/C (c)

Homo sapiens /B (3)Remember: that if scientific names are not underlined you will lose the marks!!!!

Slide61

Solution:3.1.2

DIAGRAM

A/Homo erectusDIAGRAM

B/Homo sapiensSmall cranium/brain

Large cranium/brainLess rounded cranium/skull /flatter foreheadMore rounded cranium/ skull/ foreheadPrognathus/ protruding jawsNot prognathus

No obvious chin

Pronounced chin

Slide62

Solution:

DIAGRAM A/Homo erectus

DIAGRAM B/Homo sapiens

Eyebrow ridges visibleEyebrow ridges less visibleEyes face forward

Eyes to the sideMore developedcheekbone/zygomatic archLess developed cheek bone/ zygomatic arch

Bigger lower jaw

Slightly smaller lower jaw

Learn this table too

Slide63

Something for you to do:The following essay appeared in the Nov 2013 paper 1.

4.3 Describe the structural changes to the skull that characterise the evolution of modern humans from their ape-like ancestors, and explain the significance of these changes .

Slide64

Solution:4.3

Foramen magnum - The foramen magnum was in a backward position in the ape-like beings- but in a forward/ central/ ventral position in modern humans

Significance - This represents a change from quadrupedalism in ape-like beings

- To bipedalism/(walking upright) in modern humans, leading to the following in modern humans: o Increased awareness of the environment in sensing danger/food

o Freeing of the hands to use implements/ carry objects/ weapons/ offspring o Exposure of a large surface area for thermoregulation/losing body

Slide65

Solution:Display of sex organs /breasts as part of courtship behaviour

Cranium - Modern humans have a larger cranium than the ape-like beings Modern humans have a less sloping forehead

than the ape-like beingsModern humans have a cranium that is more rounded

than the ape-like beings

Slide66

Solution:Significance - This allowed space for a larger brain

in humans than in ape-like beings, making the following possible: o Better co-ordination of movement

o Processing of a large amount of information o Processing information faster

o Development of spoken and written languages to communicate

Slide67

Solution:Jaws - Humans have smaller jaws

than the ape-like beings Humans have jaws that are non-prognathous/ flat face

compared to the jaws of ape-like beings which are prognathous/sloping face

Humans have C-shaped jaws /jaws that are gently curved compared to the U shaped jaws in the ape-like beings

Slide68

Solution:Significance

This corresponds with a change in diet from hard, raw food in the ape- like beings To softer, cooked foods in humans

Dentition/Teeth - In ape-like beings there are gaps/diastema

between incisors and canines - but no gaps between the teeth in humans - Humans have smaller teeth/incisors and canines than the ape-like beings

- Humans have flatter molars and pre-molars than the ape-like beings

Slide69

Solution:Significance

- This corresponds with the decreased need to bite and tear and an increased need to grind and chew in humans in view of the change in diet to soft, cooked food

Eyebrow ridges - Humans have eyebrow ridges that are smaller

than those of the ape-like beings Significance - There is a decreased need to strengthen the skull

of humans - due to the smaller size of the jaws

Slide70

Solution:Chin

- In humans the chin is more developed compared to the ape-like beings Significance

- Developed chin assists with speech in humans

Zygomatic arch - In humans the zygomatic arch/cheek bone is less developed than in the ape-like beings

Significance - This corresponds with the decreased need for attachment of strong muscles due to the decreased jaw size in humans

Slide71

Terminology:

Hominid: refers to the group including modern humans, chimpanzees, gorillas and orangutans.Hominin: refers to modern humans and all the extinct human species

Transitional fossils: refers to the immediate fossils between a group and their ancestorArboreal

: refers to living in treesStereoscopic vision: refers to see the depth and solidity of objects

Binocular vision: the process of looking at an object with both eyes

Slide72

Terminology:Opposable thumb

: the thumb is opposite the fingers Bipedalism: refers to a type of locomotion where the animal moves on 2 hind legs in an upright position

Dentition: refers to the development of teeth and the way they are arranged in the mouth

Prognathous: refers to the projection of the jaws and nose that leads to a pointed face.

Slide73

QUESTION 1

Characteristic/s that humans share with other primates… A. Opposable thumbs B. Binocular vision

C. Both A and B D. Neither A nor B

Slide74

QUESTION 2

Homo habilis… A. was called Handyman because he was a toolmaker. B. had a larger brain capacity than

Homo erectus. C. was the first Homo species without brow ridges.

D. was the first Homo species to leave Africa.

Slide75

QUESTION 3

An opening on the primate skulls through which the spinal cord passes… A. Foramen magnum B. Vertebral column C. Spine

D. Vertebrae

Slide76

QUESTION 4

Capable of bipedal locomotion… A. Homo erectus B. Australopithecus africanus

C. Both A and B D. Neither A nor B

Slide77

QUESTION 5

A branched diagram showing the evolutionary relationships between species… A. Cladogram B. Phylogenetic tree C. Both A and B

D. Neither A nor B

Slide78

QUESTION 6

The group consisting of modern humans, chimpanzee, gorillas and orangutans and all their ancestors is… A. Hominid B. Hominin C. Both A and B

D. Neither A nor B

Slide79

QUESTION 7

Australopithecus, Panantropus and Ardipithecus belong to… A. Hominid

B. Hominin C. Both A and B

D. Neither A nor B

Slide80

QUESTION 8

Walking on 2 legs… A. Bipedalism B. Quadurpedalism

C. Both A and B D. Neither A nor B

Slide81

QUESTION 9

A fossil that is intermediate between a group and their ancestor… A. Middle fossil B. Mean fossil C. Transitional fossil

D. None of the above

Slide82

QUESTION 10

Having a long face that sticks forward… A. Prognathous B. Non-prognathous

C. Diastema D. Flatter face

Slide83

QUESTION 11

Chimpanzee… A. Prognathous B. Non-prognathous

C. Both A and B D. Neither A nor B

Slide84

QUESTION 12

Humans… A. Prognathous B. Non-prognathous

C. Both A and B D. Neither A nor B

Slide85

QUESTION 13

Structure or parts of the body… A. Ancestor B. Anatomy C. Both A and B

D. Neither A nor B

Slide86

QUESTION 14

U-shaped jaw… A. Humans B. Australopithecus C. Both A and B

D. Neither A nor B

Slide87

QUESTION 15

Prominent brow ridges… A. Humans B. Australopithecus C. Both A and B

D. Neither A nor B

Slide88

QUESTION 16

Absence of cranial ridges… A. Humans B. Australopithecus C. Both A and B

D. Neither A nor B

Slide89

QUESTION 17

Binocular vision… A. Humans B. Australopithecus C. Both A and B

D. Neither A nor B

Slide90

QUESTION 18

Altricial development… A. Humans B. Australopithecus C. Both A and B

D. Neither A nor B

Slide91

QUESTION 19

Forward foramen magnum… A. Humans B. Australopithecus C. Both A and B

D. Neither A nor B

Slide92

QUESTION 20

Spatula shaped incisors… A. Humans B. Australopithecus C. Both A and B

D. Neither A nor B

Slide93

Solution:

C AAC

CAB

ACA

ABBBBAC

C

C

D