evolution teacher notesjemima-fieldtrip.wikispaces.com/file/view/primate+evolution.pdf · if...

Primate Evolution — Teacher Notes

VCE Biology Unit 4, Area of Study 2

Variation, Natural Selection and Evolution Teacher Notes

PPPRIMATERIMATERIMATE E E EVOLUTIONVOLUTIONVOLUTION


Primate EvolutionPrimate Evolution Teacher Notes

This program allows students to investigate the primates at Melbourne Zoo and will provide them with an opportunity to observe variation within and between species. Structural and behavioural adaptations of primates living in a number of different habitats and bioclimatic zones will be observed. The concepts of natural selection and evolution will be pre-sented, discussed and analysed in the context of explaining this variation.

Particular concepts that will be covered at the Zoo include:

• comparative anatomy, physiology and behaviour of a number of different primates;

• biogeography, taxonomy and evolutionary history of the primates;

• selection pressures and adaptations in different habitats;

• examples of divergent, convergent and parallel evolution.

Other concepts that could be discussed, in conjunction with the above, include:

• human (hominid) evolution;

• a discussion of the selection pressures and adaptations involved in evolutionary development of Homo sapiens;

• the genetic basis for natural selection;

• the relationship between phylogeny and taxonomy;

The program presented here places emphasis on students making observations of a number of different species of primates representing a broad variety of the evolutionary scope of this order of mammals. These observations can be used to make comparisons among these species and a number of generalities can be developed; e.g. habitat-based comparisons such as terrestrial versus arboreal, or biogeographic-based comparisons such as Old World versus New World monkeys. In addition, key species are used to exemplify particular concepts such as convergent evolution, speciation and adaptations to different habitats, phylogeny and taxonomy.

These notes provide information for teachers who are planning a visit to the Zoo for VCE students. Within these notes is information regarding:

• How the program meets the Study Design

• What to expect in a booked session

• How teachers can plan for the visit

• Suggested questions and answers to design School Assessed Coursework (SAC) based on the data collected

• Suggested websites to visit

Introduction

This program has been developed to meet the needs of VCE Biology Unit 4, Area of Study 2 - Variation, Natural Selec-tion and Evolution. The program provides the opportunity to collect first-hand data in order to address Outcome 2 Task 1 – an oral or written report that demonstrates evolutionary relationships using first or second hand data.

The study of evolution

The subject of evolution can be looked at from a number of viewpoints. Four different approaches that are useful for VCE students to be aware of are the historic, phylogenetic, mechanistic and ecological approaches to the study of evo-lution.

The historic approach simply looks at the evolutionary sequence of living things as revealed by the fossil record. This is not really an approach to the study of evolution but more a study of the evidence for evolution. As such, this ap-proach is an important component of any introductory study of evolution but must be considered in conjunction with the other approaches, which are process-centered.

The phylogenetic approach is concerned with determining the evolutionary relationships between species and higher taxonomic groups. This involves determining how long ago different species or higher groups came into existence and from which species or groups they evolved, using studies of the fossil record, comparative anatomy and molecular biol-ogy of similar species.

VCE Biology VCE Biology VCE Biology VCE Biology Unit 4:Unit 4:Unit 4:Unit 4: Continuity & Change Area of Study Area of Study Area of Study Area of Study 2: 2: 2: 2: Change over time


The mechanistic approach is concerned with determining the mechanisms of evolution; i.e. determining how different species and higher groups form. This approach involves the disciplines of ecology, behaviour, molecular biology and population genetics in attempting to determine how populations can become reproductively isolated and thereby poten-tially become separate species.

The ecological approach is concerned with explaining how different structural and behavioural adaptations have arisen. This involves determining potential selection pressures and attempting to explain how they have been involved in selection of the observed adaptations.

All of these approaches are important to an overall understanding of evolution and natural selection. It would be diffi-cult, if not impossible, to successfully study the evolution of a species or group of organisms via only one of these ap-proaches. For example, imagine trying to understand the processes that led to the evolution of the species Homo sapiens without a reasonable understanding of the fossil record (historic) and morphological and genetic similarities to closely related species (phylogenetic). Also important is the possible mechanisms by which the species became sepa-rated from other closely related species (mechanistic), adaptations which makes the species unique, and the possible pressures that have been involved in selecting these adaptations (ecological). Clearly, the four approaches are inter-dependent.

At the Zoo

Booked sessions

All VCE sessions are 90 minutes in duration and include time in the Discovery Centre and at enclosures around the zoo. The Zoo visit will begin with an introductory overview. This will include a discussion of the features of primates and their evolution. Students are required to collect data by observing the primate species at the Zoo. A final discus-sion will be used to review the data collected, and for students to ask questions.

We will consider the following trends in primate evolution:

• group size and social behaviour - large troupes, family groups, pairs, solitary;

• reproductive strategies - long and intensive parental care and almost exclusively single births (except tamarins and marmosets who regularly produce twins);

• locomotion - quadrupedal walking, bipedal walking, knucklewalking, brachiation;

• arboreal vs. terrestrial habit;

• communication - olfactory, visual, auditory, tactile.

These trends will be considered in terms of:

• the evolutionary history of the primates and possible phylogenetic relationships between groups;

• possible selection pressures and mechanisms resulted in the evolution of different groups;

• the adaptive significance of different structures and behaviours.

The program at the zoo is centred on the ecological approach to the study of evolution. The best use of the resources available, in the form of a number of primates in the Zoo, is to use a comparative ecological approach to the collection of information and ideas. Observations of different species are discussed in terms of the adaptations to the different habitats and biogeographic zones in which these species are found. It is important that students are made aware of the phylogenetic relationships among the groups observed, and some of the potential isolating mechanisms that may have been responsible for the separation of species throughout the evolutionary history of the Order Primates. There-fore, some attention will be paid to these points.

We encourage teachers and students to use the Zoo as a learning resource and to make the most of their day. Teach-ers or students may wish to bring cameras to take a visual record of the species observed. This might be found helpful when completing post visit activities.

Planning your visit

Student data collection sheets are available at: http://zoo.org.au/education/schools/vce/mz

We ask teachers to download and print the data collection sheets they require for their students’ visit.

Prior to the visit a Zoo educator will telephone the organising teacher to discuss the particular requirements of the ses-sion. It is beneficial if students have been introduced to the idea of evolution and have had some prior discussion about the process as outline in the pre-visit activities section.


Useful Resources and Websites

Conroy, G.C. (1990) Primate Evolution. W.W. Norton & Co. New York.

Fleagle, J.G. (1988) Primate Adaptation and Evolution. Academic Press (Harcourt Brace Jovanovich), San Diego.

Martin, R.D. (1990) Primate Origins and Evolution. A phylogenetic reconstruction. Chapman and Hall, London.

Halstead, L.B. (1978) The Evolution of Mammals. Cassell Australia.

Macdonald, D. (1984) The Encyclopaedia of Mammals. George Allen and Unwin. (An excellent general mammal refer-ence with a particularly good section on primates.)

Napier, J.R and Napier, P.H. (1967) A Handbook of Living Primates. Academic Press, London.

Napier, J.R and Napier, P.H. (1985) The Natural History of the Primates. British Museum (Natural History), London.

Rowe,N. (1996) The Pictorial Guide to Living Primates. Pogonias Press

Pre-visit activities

Natural Selection and Evolution

The basics of natural selection suggest that evolution (meaning change in characteristics) of populations of organisms occurs when there is variation in the population with respect to some characteristics. If there is a genetic basis to the variation then these differences between individuals will be inherited by the offspring of the individuals. This variation necessarily means that some individuals within a population are better equipped to survive and reproduce than others. Individuals that possess characteristics that result in a greater reproductive output will produce a greater proportion of the individuals in the next generations of the population. In these terms, evolution is the result of greater reproductive output of some individuals. Therefore any characteristic must be looked at in terms of the potential to increase the reproductive output of an individual. This means that any adaptation must be related to the potential survival and re-production of individuals and groups, populations or species.

Any discussion of the adaptive (and, by definition, evolutionary) significance of a characteristic must be done in the context of the benefit to individuals. Social structure and behaviour must he related to the ‘value’ to the individual not the group.

Evolutionary biologists refer to this ‘value’ as fitness where the fitness of an organism is determined by its ability to pro-duce viable offspring. The evolutionary analysis of the adaptive value of any feature, whether it be structural physio-logical or behavioural, must be considered in relation to the potential fitness of the individual organism that possesses the feature.

Evolutionary theory is often presented in terms of survival; e.g., the often misquoted and misinterpreted ‘survival of the fittest’. It is also important that any feature is considered in terms of the reproductive benefit to the individual. In fact an animal can survive for ever but unless it reproduces successfully then its evolutionary ‘fitness’ = 0. In some cases there may be confusion between risks to survival and reproductive benefit but students must be made aware that there is no adaptive (evolutionary) value in surviving for a long time but not reproducing (or at least contributing to the repro-ductive output of closely related individuals).

Discussion – ‘Why reproduce?’

This discussion may be used to reinforce the notion that evolution occurs by the selection of individuals and not groups, populations or species.

Q. What do animals need in order to survive?

Survival requires an animal to find and take in all its basic metabolic requirements for living: oxygen, water and food; as well as a shelter. In addition to all of this, an animal must make sure it is not eaten by another animal. Students should be able to list these requirements with a little guidance.

Q. What do animals need in order to reproduce?

Firstly, an animal must survive to reproductive age. Having successfully attained reproductive age an animal must then undertake a number of activities in order to reproduce. Students should be able to suggest these: finding and/or attracting a mate, fertilizing eggs (internally or externally), laying and protecting eggs or maintaining a pregnancy, and, for many animals, caring for young.


Q. Is there a cost in reproducing?

There is a ‘survival cost’ associated with all of the reproductive activities listed above. While engaged in any of the above activities, an animal will be reducing its own chance of survival because its ability to feed, drink and protect itself are all reduced. In addition, if parental care of eggs and/or infants is involved, then more food and water is required there is an increased chance of predation. More energy will be used up finding, building or maintaining a place to live and care for the infants.

Q. If reproduction is such a risky business, why do animals reproduce?

Some students will invariably suggest (in one form or another): ‘to ensure the survival of the species’.

Do not accept this response without comment! Suggested clarifying questions might include:

‘You mean an individual zebra or blowfly chooses to reproduce so that there will be zebras or blowflies in the fu-ture?’

Most students will see the fallacy in the original idea but will not be able to offer a reasonable alternative. It is use-ful here to consider the relationship between genetics and evolution. To simplify the problem, consider an animal that has a part of its genotype which codes for ‘do not reproduce’. This animal will live longer than an organism with a part of its genotype that codes for ‘reproduce’. However, the former genotype will not be carried into the next generation because it does not reproduce. Therefore, the only reason animals reproduce is because they have a genotype which codes for ‘reproduction’ and, to continue the logic, animals (or any other organisms) which have genotypes that code for features that allow them to reproduce more successfully than other animals will have a greater proportion of the next generation with their genes. In other words these genes will be ‘selected for’.

Other important concepts

It would be useful if students had been exposed to the concepts of geological time scale, plate tectonics and continen-tal drift and were aware of the basic classification of primates. These concepts are not essential but will assist students in understanding many of the points and participating more fully in the discussion at the Zoo.

Post-visit activities

The following are ideas for discussions and/or activities to extend the understanding of concepts touched upon in the Zoo visit. Due to the nature of the interactive discussion and the scope of the content covered during the Zoo visit, some or many of these points will all warrant further discussion in the classroom.

Teachers wishing to use the data collected at the zoo as the basis for Unit 4 Outcome 2, Task 1 may wish to include a selection of these questions/ideas as starting points or guidance for the written report.

Guided questions — General Questions

Students could first at all look at their data as a whole and see if they can identify any general concepts.

Adaptations

Q. Compose a list comparing the adaptations that aid arboreal survival compared to those that aid terrestrial survival.

Arboreal Terrestrial

Prehensile tail Short or no tail

Thumb may be shortened or residual Opposable thumb

Opposable toe Toe not opposable

Arms may be much longer than legs Pairs or groups

May be solitary or in large group Foramen magnus under skull

Foramen magnus towards back of skull

From their lists students could then go on to discuss how the method of primate locomotion has changed over time.


Q. Using your list, discuss how primate locomotion has changed over time.

Students should be able to identify that over time primates have become more suited for life on the ground and biped-alism. Many monkeys stand upright and there are some that can walk bipedally. All of the great apes show the inclina-tion and the ability to walk on two legs – with varying degrees of success.

Toes have shortened. The big toe, instead of being opposable, has moved around to help the foot become a platform for walking and acts as a point of propulsion when moving.

The location of the foramen magnus has changed from the back of the skull to under the base of the skull, allowing upright primates to look directly in front of their body, (rather than up in the sky if it hadn’t moved.)

Students with a more in depth grasp on how primate locomotion has changed over time should identify that primates have changed from quadralpedalism to brachiation to knuckle walking to bipedalism.

Primate communication

Q. What changes have occurred in primate communication through time? Comment on any trends.

Students should be able to identify the following trends in communication:Reliance on scent has lessened (e.g. noctur-nal prosimians depend heavily on scent for communication, and diurnal prosimians such ring-tailed lemurs have ‘scent fights’; coating their tails with scent and waving them one another. New world monkeys have specialized glands on the chest, neck or genitals that not only mark territory but also advertise age, sex and social ranking. Old world primates have fewer scent glands and the move towards visual dominance is evident in species such as baboons, where the swelling of the females behind during oestrous acts as a visual sign. Reliance on scent has not completely vanished though – even human behaviour is influenced by pheromones, even though we may not be aware of it.)

The scope and sophistication of vocalisations has increased (e.g. pro-simians have relatively few vocalisations, whereas many arboreal new and old world primates have ‘spacing’ calls to inform others of their territory, as well as ‘contact’ calls to keep track of those in their group. Most diurnal arboreal primates have warning calls to alert others of the presence of danger; some have different calls for each danger type.)

Facial expression has increased in complexity and range (e.g. prosimians with their fixed upper lip are unable to physi-cally make a diverse range of faces, whereas orangutans appear to have many that are similar to ours.)

Appearance of young

Q. Do any juvenile primates have a different coat colouration to the adults of their species? List these and how they vary.

Young white-cheeked gibbons are the gold buff colour of the females (adult males are black).

Juvenile colobus monkeys are white (adults are black and white).

Juvenile gorillas have a white tuft on their tail, which is eventually lost.

Q. Choose one of the examples you have listed and explain how young having different colour-ation to adults could be of advantage.

White-cheeked gibbon: A gold infant may camouflage against the fur of its mother. As the infant becomes more inde-pendent and spends more time away from its mother, black fur may provide better camouflage in the dark forest.

Colobus monkey: this species practices ‘alloparenting’. All females in the group carry and look after the young. Having white baby allows females to identify the young easily and the mother to easily keep track of where her young is.

Gorilla: all members of the group appear to be aware of the fact that young have not learnt how to interact appropri-ately and are tolerant of any behaviour that would be unacceptable from mature members of the group (e.g. young have been observed climbing on and over resting dominant males with no repercussions.) This accepting behaviour disappears when the tuft disappears.

Guided Questions—Species Specific Questions

A variety of species-specific questions could be developed relating body size to habitat and social structure and repro-ductive patterns. When comparing two or more species important aspects to consider are:

• the evolutionary importance of the interactions among: habitat, habit, behaviour, social structure, morphology and reproductive biology;


• the phylogenetic and taxonomic relationships between the apes and humans.

Students should describe similarities and differences in physical structure, social grouping and behaviour, then relate these to the differences in behaviour and habitat. All of these social strategies should be considered in conjunction with the respective habitats, reproductive patterns and general ways of life of each species. All of these are interdependent and must be considered as an evolutionary package. It is simple enough to examine one aspect in isolation from the others and make simple evolutionary interpretations but a more interesting picture of evolution comes when the evolu-tionary consequences of a change in habit or habitat are considered as a package.

For example, take the problem of social structure versus body size in arboreal primates. A small arboreal animal can live in a relatively large group; e.g., Squirrel Monkey, but when body size increases, e.g. gibbons, group size decreases to pairs.

Q. How has the habitat of the gorilla (terrestrial) and orang-utan (arboreal) influenced their social structure? In turn, how has this influenced the development of verbal communication?

A large animal such as an orang-utan or gorilla could not possibly survive living in large groups if they are restricted to living in trees. Consequently orang-utan is basically solitary; the gorilla, on the other hand, has retained social group-ings but moved to a basically terrestrial existence.

A solitary lifestyle is thought to be the reason for Orang-utans typically displaying little communication apart from the ‘kiss-squeak’ from young to mother, and territorial ‘long calls’ from dominant males. Gorillas on the other hand have numerous vocalisations: humming, hooting, coughing, chuckling, etc.

Mandrill and Hamadryas Baboon—Species Specific Questions

Students could compare the Mandrill and the Hamadryas Baboon. These are an interesting case study because of their strong similarities but different habitat.

Q. From your observations, compose a list of the similarities and differences between the Man-drill and the Hamadryas Baboon.

Similarities: size, general body shape;

Differences: colour, habitat type (rainforest, desert), group size and dynamics (you may need to help with this).

Conclusion: these two species are similar in basic structure but there are several major morphological and have behavioural differences.

Q. Even though they live in different habitats, there is a basic similarity between the Mandrill and the Hamadryas Baboon. Why?

Students should be encouraged to discuss the two major possibilities:

• close phylogenetic relationship; i.e. the two species are closely related and therefore would be expected to be similar in structure. This may need a brief discussion

• similar habit ; i.e., the two species are basically terrestrial (although Mandrills do spend time in trees) and therefore will have evolved similar adaptations to living on the ground.

In fact both mechanisms are partially involved. The baboon group of monkeys (to which these two species belong) probably evolved as a response to filling an available ecological role in Africa: the middle-sized, terrestrial, generalist omnivore. It is unclear as to whether the forest Mandrills and Drills (genus Mandrillus) evolved independently of open country Baboons (Papio and Theropithecus) or they all evolved from a single lineage and one group established in the forest and the others in more open country. It is clear from the basic structural similarities that there has not been great differentiation.

This may be due to:

• relatively recent evolution or;

• despite the differences in habitat types filled by baboons (from desert to grassland and rainforest), there is a basic body shape and structure required for ground living.

Q. Suggest why the Mandrill may have evolved to have such colourful markings.

There is more than one possible correct answer here.

Mandrills may have evolved colourful bodies so that it is easier for members of their troupe to see them in the relatively dark rainforest.


Mandrills may have evolved colourful bodies in order to advertise to the opposite sex; in an area where food is plentiful, males in particular often develop other methods of attracting females.

Tamarins and Marmosets—Species Specific Questions

Tamarins and Marmosets belong to a distinct group of New World primates, classified as the Subfamily Callitrichinae. They are easily recognized by their small size and clawed digits. They are a particularly homogeneous group despite the many species; i.e. the only obvious differences between species are the variations in colour and ‘head-gear’ (many species have elaborate facial and/or cranial hair).

Several aspects of evolution can be exemplified by this group:

• possession of claws

Q. Why should these species have claws on their digits when all other monkeys and apes have nails?

This is an example of a re-evolved characteristic - insectivores have claws, monkeys have nails, so it would appear that the marmosets and tamarins are the most primitive monkeys. However, embryonic examination indicates that claws are secondarily derived from embryonic nails. The most likely explanation for this apparently ‘backward’ evolu-tionary step is that marmosets and tamarins are too small to hold onto large branches using an opposable grip.

Q. Compare the different species of marmosets and tamarins. List some of the differences.

Students should note that the differences are superficial; i.e. mainly different in appearance - different colours, facial markings - rather than structural. There are approximately 34 species in the subfamily Callitrichinae (marmosets and tamarins) living high in the trees of the forest areas of Central America and northern South America. Whereas the only other subfamily of primates with similar numbers of species, the Cercopithecinae (Old World monkeys), has approxi-mately 39 species distributed from South Africa to Japan and South-east Asia and occupies a wide variety of habitats ranging from deserts to tropical rainforests, and from terrestrial to arboreal in habit.

Q. Explain why the marmoset and tamarin group is so diverse in terms of numbers of species while their geographic range is comparatively limited.

Individuals of many species never actually go onto the ground, such is their level of arboreal dependence. Combine this with a relative abundance of food and other resources in their tropical rainforest habitat and the limited need and/or ability for groups to move over large distances. It would therefore have been easy for small populations of these ani-mals to become isolated from each other in a relatively small and apparently homogeneous habitat. When populations become isolated, they will be subjected to different selection pressures (due to small or large differences in their habi-tats) and therefore will begin to evolve in different directions. If this isolation remains for long enough then populations may evolve to become different enough to be separate species.

Lemurs—Species Specific Questions

Q. What characteristics indicate the primitive nature of the Lemurs compared with the mon-keys and apes?

Students should come up with characteristics such as elongated snout, ‘wet’ nose, mobile ears and angled eyes. Dis-cuss the distinction between phylogenetic relationship and the descriptive nature of the use of the term ‘prosimian’.

Lemurs are representatives of the primate group known as Prosimians. This group traditionally has been used as a taxonomic grouping and includes lorises and tarsiers. However, most primate taxonomists now separate the tarsiers from the lemurs and lorises and include them in a larger grouping with monkeys and apes. Therefore the term ‘prosimian’ is used only as a descriptive term indicating the relatively ancient nature of the groups rather than their taxonomic positions or phylogenetic relationships. Lemurs are now found only on the island of Madagascar.

White-cheeked (Concolour) Gibbon—Species Specific Questions

Sexual dichromatism - Different sexes having differing colouration

Q. Is there a difference in the colour of the male and female this species?

Male is black and the female, golden or buff.

Q. Why is this species the only gibbon to show such dimorphism?

Other gibbon species are black, grey or dull brown and occasionally display colour dimorphisms but these are not sex-related. If the dark or dull colouration is good camouflage in a dark forest why has the species evolved females with


a bright colouration? It is generally accepted that gibbon species pair bond for life but it is believed that this species may exhibit polygamous reproductive patterns; i.e. one male to more than one female. This would suggest that it might be advantageous for the adult female to be easily seen and identified by males.

Movement and limb structure

A discussion centred around the evolution of various modes of locomotion in trees (including: jumping, running along branches, brachiation) would be useful for developing the idea of a number of possible structural adaptations to per-form a particular function in a similar habitat.

Begin with an in-depth analysis of one animal; e.g. gibbon.

Q. How do the gibbons move?

Swinging from branch to branch using hands to grip. This method of locomotion is called ‘brachiation’.

Q. Describe the relative arm and leg length in comparison with other primates.

Gibbons have arms that are much longer than their legs. Most other arboreal primates, except orang-utans, have arms and legs of approximately the same length.

Q. What is the value of long arms to a gibbon?

Long arms enable gibbons to swing greater distances. This is related to both reach (a long arm will reach further than a short arm) and circular velocity (a longer arm will generate a faster movement of the swinging body, which means that greater distances can be traveled between branches).

Q. Why don’t all arboreal animals have long arms?

Other arboreal primates utilise other modes of locomotion in trees; e.g. running along branches (Squirrel Monkey), leaping (Colobus), using a prehensile tail as an added gripping appendage (Spider Monkey).

Q. Gibbons have no tail. Why?

An animal with a tail would have an extra appendage that gets in the way while brachiating.

Q. Gibbons have long hands with long fingers but very small thumbs. Discuss the significance of this hand structure to their method of movement.

The long hands and fingers act as hooks for grip when brachiating. An elongated thumb is probably a hindrance when brachiating so it has been reduced.

A continued discussion of other arboreal primates and their methods of locomotion can be centred on different struc-tures and different functions.

Q. Many arboreal primate species do not brachiate. How do they move and what differences in body structure do they have which may assist their mode of movement.

Students should recall the Black and White Colobus (jumps from branch to branch), Squirrel Monkey (runs along branches) and the Black-handed Spider Monkey (hangs from its long arms and legs and prehensile tail). These are primates that have different body structures and methods of movement in trees. Discuss the relationship between limb structure and function in movement using these examples.

Q. What is the difference between parallel and convergent evolution? Provide an example of each.

Students should be able to see the distinction by looking for the taxonomic (and therefore phylogenetic) relationship between the relevant species. The Mandrill and Macaque are similar because they have evolved in the same direction; i.e. in parallel, from a common ancestor whereas the Ringtail Possum and the Spider Monkey have evolved prehensile tails independently from two distinct evolutionary lineages; i.e. their features have converged.

Ebony Leaf Monkey and Black & White Colobus—Species Specific Questions

Infants of these two species are coloured very differently from the adults, whereas infants of many other primate spe-cies are the same colour as the adults.

Q. Why have infants of a different colour?

In both these species the infant colour is not just different from the adults; rather it is bright (orange in the case of the Ebony Leaf Monkey and white in the Colobus) whereas the adults are dark. These two species also exhibit communal sharing of care for the young. A brightly-coloured infant would be easier for adults in the group, including the mother, to see where it is.


Black-handed Spider Monkey—Species Specific Questions

Compare this species with other monkeys with respect to structure of the face (in particular, the nose) and tail.

Q. Can a generalized conclusion be drawn with respect to the facial and tail structures of mon-keys in relation to their geographic distribution and taxonomic status?

New World monkeys (Superfamily Ceboidea) are the only primates with prehensile tails, (although not all have devel-oped this feature). In addition, they have flat noses with a broad septum and nostrils that face out to the sides, whereas Old World monkeys (Superfarnily Cercopithecoidea) have noses with a narrow septum with nostrils facing forward or downwards.

Q. How did these differences arise?

It is easy enough to explain the adaptive value of a prehensile tail to an arboreal animal but if it is of so much value why don’t all monkeys have one? It is important for students to be aware that evolution does not always come up with the best possible features. A prehensile tail like that of the Spider Monkey is an obvious advantage for an arboreal habitat but some species of New World monkeys do not have one. This would suggest that the feature evolved in some American monkeys after the separation of South America from Africa. Prehensile tails have not evolved in Old World monkeys. This is not because they would be of no advantage; rather no genetic mutation providing the code for a tail that could wrap around a branch has occurred in Old World monkeys (yet!). Such events have, however, occurred in other groups of animals; e.g., the Ringtail Possums of Australia and the Binturong (a large civet) of Asia both have pre-hensile tails used for gripping branches. This is an example of convergent evolution where similar structures evolve independently in unrelated groups.

It is very difficult to explain an adaptive advantage in the differences in facial structure. How is it that these differences occurred? It appears that the Old World nasal structure is primitive, in that all primitive primates have this type of nose. The New World nasal structure appears to be a case of an evolutionary legacy of a 'random' difference. When the South American continent became separated from the African continent, there were monkeys on both continents (as well as Eurasia). All the present day descendants of the South American monkeys must have evolved from a group with wide noses and outward facing nostrils, which by chance, ended up on the South American side of the separation.

Additional Information

For more information on origins, taxonomy and phylogeny of primates, see the Primate Evolution Teacher Resource Book : http://zoo.org.au/education/schools/vce/mz

Suggested Responses to Student Data Sheet

Please see over the page for suggested answers to the student data sheet, to assist your students.


Primate Feature Shrew Slow Loris Ring Tailed Lemur

Black and White Lemur

Ecological Niche

Habitat (Include level found at eg. emergent canopy, forest floor etc.) Diet Time of most activity?

- Rainforest - Arboreal - Eggs, insects, other small animals - Diurnal

- Tropical rainforest, - Arboreal - Fruit, insects, sap - Nocturnal

- Dry forest/srcub, - Arboreal and occa-sionally terrestrial - Fruit, leaves, sap - Diurnal

- Tropical rainforest, - Arboreal - Fruit, insects, sap - Diurnal, may be noc-turnal in Summer

Limb Length

Express as ratio; forelimbs (arms) compared to hindlimbs (legs).

- 1:1 - 1:1 - 2:3 - 2:3

Hands

Are thumbs present? Are they opposable? Nails or claws present?

- 5 digits - Claws

- Opposable thumbs - Nails



Feet

Are the big toes oppos-able? Compare size to hand size. How are they used?

- Non– opposable big toe - Same size as hands - Used for climbing, leaping, running

- Opposable big toe - Same size as hands - Used for climbing, (do not leap).

- Opposable big toe - Same size as hands - Used for climbing, leaping, walking

- Opposable big toe - Same size as hands - Used for climbing, leaping, walking

How do they move?

Do they walk on all four limbs? On their knuckles? Do they brachiate?

- Run along branches - Move very slowly us-ing all 4 limbs - Often up side down, will hang and eat in this position.

- All 4: Climbing, leap-ing, walking quadraped-ally

- All 4: Climbing, leap-ing, walking quad-ralpedally

Tail

Is it present? Is it used it in any way?

- Long tail

- No tail - Long tail - Balance and commu-nication, (often coated in scent and waved)

- Long tail - Balance and commu-nication, (often coated in scent and waved)

Sexual Dimorphism

Is there any difference in appearance between males and females?

- No - No - No - No

Group size Do the animals live in groups, pairs, or are they

solitary?

- Pairs - Solitary - 5 to 30, - May be more than one male - Females dominant

- Solitary

How do they communi-cate?

e.g. olfactory, visual, audi-tory, tactile.

- Olfactory - Olfactory - Olfactory - Auditory

- Olfactory

Ears Are fixed, mobile, furry,

bald?

- Mobile, furry - Mobile, furry - Mobile, furry - Mobile, furry

Nose Wet or dry?

- Wet - Wet - Wet - Wet

Any other observa-tions?

Nose? Ears? Eyes?

Gestation/Oestrous cycle?

- Eyes angled - Gestation approx. 45 days - Two or three young

- Eyes very large and angled - Gestation 191 days, single birth

- Eyes angled - Gestation approx. 138 days days, single birth or twins - Have specific mating season

- Eyes very large and angled - Gestation 191 days, single birth - Have specific mating season

Suggested Suggested Suggested Suggested Answers Answers Answers Answers to to to to

Student Student Student Student Data Data Data Data SheetSheetSheetSheet


Primate Feature Golden Lion Tamarin

Emporer Tamarin Cotton Top Tamarin

Common Squirrel Monkey

Ecological Niche


- Lowland rainforest, - Arboreal - Fruit, insects - Diurnal,

- Lowland rainforest, - Arboreal - Fruit, insects, sap - Diurnal,

- Rainforest, - Arboreal - Fruit, insects, sap - Diurnal,

- Primary and secon-dary forest, - Arboreal - Fruit, insects, seeds - Diurnal,

Limb Length


- 1:1 - 1:1 - 1:1 - 1:1

Hands


- Opposable thumbs - Claws




Feet


- Opposable big toe - Same size as hands - Used for climbing, leaping, running




How do they move?


- All 4: Climbing, leaping, running quadralpedally




Tail


- Long tail - Balance




Sexual Dimorphism


- No - No - No - No


solitary?

- Family group of 2 to 8, may be up to 16 tempo-rarily

- Up to 9 in group - Up to 7 in group - Up to 300 in group

How do they communi-cate?

e.g. olfactory, visual, auditory, tactile.

- Vocalisations (up to 17)

- High pitched calls - Bird like calls - Clicks and squeals - Visual displays


bald?

- Fixed - Fixed - Fixed - Fixed

Nose Wet or dry?

- Dry - Dry - Dry - Dry

Any other observa-tions?

Nose? Ears? Eyes?


- Eyes slightly angled - Gestation 128days, single birth - Have oestrous cycle of 2-3 weeks - Twins

- Eyes slightly angled - Gestation approx. 140 days, - Twins

- Eyes slightly angled - Gestation approx. 130 days, - Twins

- Eyes slightly angled - Gestation approx. 150 days - Oestrous cycle 7 –13 days - Single birth


Primate Feature Black Handed Spider Monkey

Lion Tailed Macaque

Hamadryus Baboon

Mandrill

Ecological Niche


- Rainforest and mon-tane forest - Arboreal - Fruit, insects, leaves - Diurnal,

- Rainforest between 610 and 1070 m above sea level - Arboreal, but will for-age on ground - Fruit, insects, roots - Diurnal

- Semi desert - Generally terrestrial - Generalist omnivores - Diurnal

- Think Rainforest - Generally terrestrial - Generalist omnivores - Diurnal

Limb Length


- 1:1 - 1:1 - 1:1 - 1:1

Hands






Feet


- Opposable big toe - Same size as hands - Used for climbing, leap-ing, running

- Opposable big toe - Same size as hands - Used for climbing,

- Non-opposable big toe - Same size as hands

- Non-opposable big toe - Same size as hands

How do they move?



- All 4: Climbing, rarely leap

- All 4 - All 4

Tail


- Long tail - Prehensile


- Short tail: acts like rudder when running

- Short tail: acts like rudder when running

Sexual Dimorphism


- No - No - Yes: males have long silvery grey hair with large canines. Females and juveniles light sandy brown colour.

- Yes: males larger with colourful backside and large canines.


solitary?

- Varies from 2 to 30, usually in sub groups of 6 with 1 male

- Varies from 4 to 34, usually 10 to 20 with 1 to 3 adult males

- Troups of approx. 40 including harems of 10.

- Troups of approx. 150, made up of groups of 50.

How do they communicate?


- Contact is maintained using sight

- 10 calls identified - Visual includes body posturing and facial expressions

- Vocalisations - Visual includes body posturing and facial expressions

- Vocalisations - Visual includes body posturing and facial expressions


bald?


Nose Wet or dry?


Any other observations?

Nose? Ears? Eyes?


- Eyes slightly angled - Gestation approx. 230 days, - Single birth - Young black

- Eyes slightly angled - Gestation approx. 170 days, - Single birth

- Eyes slightly angled - Gestation approx. 170 days - Oestrous cycle 30 days - Single birth

- Eyes slightly angled - Gestation approx. 220 days - Oestrous cycle 33 days - Single birth


Primate Feature De Brazza’s Mon-key

Eastern Black and White Colobus

Ebony Leaf Monkey

White-cheeked (Concolour) Gibbon

Ecological Niche


- Forested zones - Arboreal and terres-trial - Fruit, leaves, in-sects, grains - Diurnal

- Dry or moist secon-dary forests where trees are not too dense - Arboreal - Leaves - Diurnal

- Mangrove and sub-coastal forests - Arboreal - Fruit, flowers, leaves, seeds, wood, crops - Diurnal

- Rainforest - Arboreal - Fruit, eggs, nuts, insects - Diurnal

Limb Length


- 1:1 - 1:1 - 1:1 - 2:1

Hands



- No thumbs (have been lost) - Nails

- Opposable thumbs (short) - Nails


Feet


- Opposable big toe - Same size as hands - Used for climbing, and running



- Opposable big toe - Same size as hands - Used for climbing, leap-ing, running

How do they move?


- All 4: Climbing and running quadralped-ally

- All 4: Climbing, leap-ing, running quad-ralpedally

- Quadralpedal on ground - Semi-brachiation in trees

- Brachiation - Will move on ground with 2 or 4 limbs

Tail


- Long tail - Prehensile in young, used for balance in adults

- Long tail

- Long tail - Prehensile

- No tail

Sexual Dimorphism


- No - No - No - Male is black, female buff


solitary?

- Groups of about 10 with 1 male

- May range from 3 to 15, with adult male and females with young

- Groups of 13 to 37, usually with 2 females to 1 male

- Family groups of up to 6 with parents and offspring



- Vocalisation - Body language

- Limited vocalistions from male - Facial expressions and body language

- Facial expression and posture - Limited vocalistions, such as alarm calls

- Vocalistion - Facial expressions and body language - Touch


bald?


Nose Wet or dry?



Nose? Ears? Eyes?


- Eyes forward - Gestation approx. 170 days - Single birth

- Eyes forward - Gestation approx. 4.5 to 5.5 months - Single birth - Young is completely white

- Eyes forward - Gestation approx. 200 days, - Single birth - Oestrous 30 days

- Eyes forward - Gestation approx. 205 days - Single birth - Young is completely buff, will change if male - Oestrous 30 days


Primate Feature Sumatran Orang-utan Western Lowland Gorilla

Human

Ecological Niche


- Rainforest - Arboreal - Fruit, eggs, nuts, insects - Diurnal

- Lowland tropical rain-forest - Terrestrial, females and young nest in trees at night - Leaves, fruit, shoots, flowers - Diurnal

Limb Length


- 3:2 - 4:3

Hands




Feet

Are the big toes opposable? Compare size to hand size. How are they used?

- Opposable big toe - Same size as hands - Used for climbing and carrying

- Non-opposable big toe - Same size as hands - Used for walking and climbing

How do they move?


- A unique climbing/semi-brachiation. - Walk on knuckles - Never jump

- Walk on knuckles

Tail


- No tail

- No tail

Sexual Dimorphism

Is there any difference in ap-pearance between males and females?

- Male is larger (110kg vs 45kg) - Males have large cheek pads and canines

- Male is larger than females, with larger canines and saggital crest

Group size Do the animals live in groups,

pairs, or are they solitary?

- Family groups of up to 6 with parents and offspring

- 1 male with 7/8 fe-males and young


e.g. olfactory, visual, auditory, tactile.

- Vocalistion limited mainly to territorial calls of males - Facial expressions and body language - Touch

- Many vocalistions - Facial expressions and body language - Touch

Ears Are fixed, mobile, furry, bald?

- Fixed - Fixed

Nose Wet or dry?

- Dry - Dry


Nose? Ears? Eyes?


- Eyes forward - Gestation approx. 230 days - Single birth (twins rarely) - Approx. one young every 7 years - Oestrous 30 days

- Eyes forward - Single birth - Young have white tail tuft - Oestrous 31 days


Black Handed Spider Monkey

Lion Tailed Macaque

Bolivian Squirrel Monkey

Mandrill Hamadryas Baboon

Slow Loris

Siamang

Ring Tailed Lemur

Western Lowlands Gorilla

DeBrazzas Monkey

Cotton Top Tamarin

White Cheeked Gibbon

Golden Lion Tamarin

Emperor Tamarin

Black and White Colobus

Black and White Lemur

Appendix 1—Melbourne Zoo Primate Identification

Primate Evolution —

Teacher Notes

Lemurs Galagos Lorises

60

Pro-Simians Simians

45

New World

Monkeys

Old World

Monkeys

30

Gibbons Orangutans

Gorillas Humans Chimpanzees

22

15

10

Hypothesized divergent evolution of primates (in millions of years ago)

Appendix 2


Melbourne Zoo Healesville Sanctuary Werribee Open Range Zoo Post Office Box 74 Badger Creek Road K Road

Parkville Vic 3052 Healesville, Vic 3777 Werribee, Vic 3030

Ph: 61 3 9285 9355 Ph: 61 3 5957 2819 Ph: 61 3 9731 9635

Fax: 61 3 9285 9340 Fax: 61 3 5957 2873 Fax: 61 3 9731 9644

Discovery & Learning is a partnership between

© These sheets may be reproduced for teaching purposes. Permission to reproduce them for other pur-

poses may be obtained from the Discovery and Learning at Melbourne Zoo.

evolution teacher notesjemima-fieldtrip.wikispaces.com/file/view/primate+evolution.pdf · if...

Documents