Question

a)  that Primates rely heavily on sight and less on smell compared to other mammals. State the four evolutionary changes reflecting this statement. Include a brief description of each change

b) Considering the Tarsiers as a group .Describe their geographic location and ecological characteristics.

c) List ten (10) physical (structural/anatomical) characteristics of the anthropoids that distinguish them from the lemurs and lorises.

d) For the orangutans, list (1) the geographical range; (2) locomotion; (3) ecological niche; and (4) sexual dimorphism. do the same for gorillas

e) Why is nonhuman primate extinction of grave concern?

Answer 1

a)

Geographic Location:

The Tarsier is a small species of primate that is found inhabiting the well-vegetated forests on a number of islands in south-east Asia. Tarsier are intermediate in form between lemurs and monkeys, measuring only about 9–16 cm (3.5–6 inches) long, excluding a tail of about twice that length. Tarsiers are lemurlike in being nocturnal and having a well-developed sense of smell. However, like monkeys, apes, and humans, the nose is dry and hair-covered, not moist and bald as is that of lemurs. The eyes and placenta are also simiiform in structureAlthough fossil records show that Tarsiers would have once been found in mainland Asia, Europe, North America and in Africa, modern Tarsiers are today restricted to just a handful of islands in Malaysia, Indonesia and the southern Philippines. Despite constant debate amongst scientists over the naming and classification of Tarsier species, in 2011 there were 18 different sub-species of Tarsier described that are split into three groups generally depending on their geographic location, which are Western Tarsiers, Eastern Tarsiers and Philippine Tarsiers. Although science is slowly discovering more and more about Tarsiers in the wild, data can be hard to collect due to their shy and elusive nature and coupled with the constant confusion over the classification of separate species, makes conservation efforts difficult.

Ecological Characteristics

Tarsiers are the only entirely carnivorous primates, preying on insects, lizards, and snakes. Clinging upright to trees, they press the tail against the trunk for support. Their grip is also aided by the tips of their digits, which are expanded into disklike adhesive pads. Tarsiers move through the forest by launching themselves from trunk to trunk propelled by their greatly elongated hind limbs.The Tarsier is a unique animal as they are the only completely carnivorous primates in the world. Under the cover of night, Tarsiers sit clinging to vertical branches where they wait motionless and survey their surrounds 180 degrees each way watching closely with their huge eyes and picking up on even the tiniest noise with their incredibly sensitive hearing. Once food has been located, the Tarsier moves slightly closer to it before leaping onto it and catching it with its front hands. The long fingers and toes of the Tarsier enable it to also trap flying prey mid-air and provide an almost cage-like device to prevent it from escaping before the Tarsier has killed it. Insects make up the bulk of a Tarsier's diet along with small vertebrates such as frogs, lizards and small birds. Some Tarsier species are even known to hunt poisonous snakes and are able to actually catch small bats in the air. Tarsiers hold their prey in their front hands to eat it using their strong jaws and teeth, and are known to have wide mouths for their small size to enable them to consume larger prey.

B) Physical (structural/anatomical) characteristics of the anthropoids that distinguish them from the lemurs and lorises:

Prosimians 1. includes about 50 species; lemurs in Madagascar, lorises in West Africa and Southeast Asia and bushbabies in Africa 2.smallest in size 3. arms shorter than legs 4.strong hind legs for leaping and clinging to tree trunks 5. most are nocturnal 6.tooth comb 7. some have visible tails grooming claws 8. wet nose and dog-like snout, developed sense of smell 9. light-reflecting eyes

Monkeys 1.includes more than 200 species, New World in South and Central America, Old World in Africa and Asia, and tarsiers in Southeast Asia 2.smaller in size 3.arms equal in length to or shorter than legs 4.limited shoulder rotation 5.diurnal (active during the day) chest deeper than broad 6.most have visible tails 7.nails on all digits (except Callitrichidae—marmosets and tamarins) 8.dry nose, lack snout, weak sense of smell (large teeth may extend the snout)

Apes 1.includes about 14 species; gorillas, bonobos, and chimpanzees in Africa, and orangutans and gibbons in Southeast Asia 2. larger in size (except for gibbons) 3.arms longer than legs 4.full shoulder rotation 5.diurnal 6.broad chest 7.no tails 8.nails on all digits 9.dry nose, lack snout, weak sense of smell 10..lack of hair on face

c) Orangutan's the geographical range:

In the past orangutans ranged throughout Southeast Asia all the way into southern China and were found on the island of Java and in southern Sumatra. Orangutans are now found only on the islands of Borneo and Sumatra with the Sumatran species limited to the northern part of the island. Sumatran orangutans are fragmented into 9 separate populations, all of which are located in the Indonesian provinces of Aceh and North Sumatra. Bornean orangutans are much more widely distributed and are found in Kalimantan, Sabah, and Sarawak. No permanent orangutan populations have been reported from Brunei.

Orangutans on both islands primarily inhabit peat swamp forests, tropical heath forests, and mixed dipterocarp forests at altitudes of less than 1,000 meters (3,281 feet) above sea level. Orangutan population density has been shown to correlate positively with the level of fruit availability. This means that in forests where a higher abundance of fruit and fewer or less drastic periods of seasonal fruit shortages occur, orangutans are found to live at much higher densities than in other forests. Generally speaking,since Sumatran forests seem more productive than forests in Borneo, Sumatran orangutan populations are denser than Bornean orangutan populations. Orangutans living in peat swamp forests live at higher densities than in other forest types

Orangutan's Locomotion:

Orangutans are the largest arboreal animals in the world, usually spending over 95% of their time in the trees. They are also among the most sexually dimorphic of primates with males much larger than females. Fully developed adult males can weigh up to 300 pounds, while adult females weigh less than half that weight. Adult male orangutans can reach a height of five feet and can have eight foot arm spans. Orangutans spend almost 100% of their time – eating, sleeping, and travelling – in the forest canopy. Their bodies are adapted to their unique method of arboreal locomotion – called quadrumanous scrambling.” The orangutans’ long, narrow hands and feet are especially useful for grasping branches. Their opposable thumbs and big toes are short to facilitate the hook-like function of hands and feet, particularly in brachiation and hanging on to tree branches. They have highly mobile hip and shoulder joints that allow them to easily move from branch to branch and tree to tree. In orangutans the ligament, ligamentum teres, that binds the top of the femur to the pelvis in humans is much modified. Thus, orangutans can easily do yoga-like poses – like putting their legs behind their heads – that in humans are restricted to the most accomplished yoga practitioners or professional acrobats and circus performers. Furthermore, unlike the other great apes, who are usually black (“Snowflake”, the white gorilla, being an obvious exception), orangutan bodies are covered in thick reddish brown hair.

Orangutan's ecological niche:

60% fruit and other plant materials including leaves, bark, flowers, and nuts, occasionally insects and small mammals.
Primarily fruit and plant eaters, orangutans play an essential role as seed dispersers throughout the forests of Indonesia as they digest and eliminate waste. They choose select green leaves and shoots, and in doing so act as pruners that aid in regenerating plant growth. The small food patches in Bornean forests, which cannot support more than one orangutan, force them to remain solitary or semi-solitary, and limits their social interactions.

Orangutan's Sexual dimorphism:

The orangutan is widely recognized as a highly dimorphic species. An ontogenetic approach to the study of sexual dimorphism can assist researchers in understanding both where and when these differences develop. In this study, 357 orangutans from Borneo were divided into five developmental stages representing infancy to mature adulthood. Three-dimensional (3D) coordinate data from 16 landmarks representing the face and palate were analyzed by means of a Euclidean distance matrix analysis (EDMA), a quantitative method for the comparison of forms. Three separate analyses (an age-specific static comparison of forms, a sex-specific analysis of growth trajectories, and an intersex comparison of patterns of relative growth) were carried out with the intent to describe the rate, timing, magnitude, and pattern of growth in the orangutan face and palate. The results indicate that generally males and females share a similar, but not identical, pattern of growth or local form change, but differ in growth rate, timing, and magnitude of difference. Dimorphism in the face and palate can be localized in infancy and traced throughout all age intervals. Orangutan females grow slightly faster than males from infancy to adolescence, at which time male growth exceeds female growth. Female growth ceases with the advent of adulthood, while male growth continues (i.e., both the number and magnitude of the dimorphic dimensions increase). Males and females are similar in facial dimensions and growth related to the orbits, upper face, and palate width. They maintain these similarities throughout development. However, they differ in facial and nasal height, palate length, snout projection, depth of the nasopharynx, and hafting of the face onto the skull. The face broadens and the zygomatic bone flares dramatically in adult males, corresponding to the development of cheek pads. While growth patterns are similar between the two sexes, they differ in the lateral orbit, snout projection, and hafting of the face onto the cranium. Adult dimorphism is the result of growth patterns experienced throughout life, and it is not equally expressed across the cranium. An understanding of patterns of dimorphism, along with the magnitude of difference, may be helpful for interpreting dimorphism in the fossil record.

Gorrilla's Geographic Range:

Mountain gorillas are found in two separate locations: the Virunga range of extinct volcanic mountains on the borders of the Democratic Republic of Congo (DRC), Rwanda and Uganda, and in the Bwindi Impenetrable National Park in Uganda. Some primatologists believe the Bwindi gorillas may be a separate subspecies.

Gorrilla's locomotion:

Spending the majority of their lives on the ground, the main locomotion pattern of gorillas is quadrupedal knuckle-walking although they do climb and spend limited amounts of time standing bipedally. Because of their sheer size, adult gorillas must climb near the main trunk of a tree or on large branches while juveniles and adolescents are more agile.

Gorillas live between 30 and 40 years in the wild and up to 50 years in captivity

Gorilla's Ecological Niche

Mountain Gorilla Ecosystem

Mountain gorillas, or eastern gorillas, live in the Virunga Mountain Range, which consists of volcanoes. Their habitat is in the Democratic Republic of Congo, Uganda and Rwanda. The highland cloud forests of the range and sometimes the highland meadows are where they live. Not only are mountain gorillas extremely endangered due to poaching and habitat destruction, but their flora and fauna rich ecosystem is as well. Cloud forests around the world are in danger due to climate change and deforestation.

Cross River Gorilla Ecosystem

There are fewer Cross River gorillas than any other gorilla subspecies -- between 300 and 400. They live in Nigeria and Cameroon on the border of both countries. Cross River gorillas dwell primarily in mountain forests. The ecosystems of every community of Cross River gorillas are at risk of deforestation and hunting. Removal of the forests that these few gorillas live in would eliminate their food supplies.

Western Lowland Gorilla Ecosystem

Western lowland gorillas have the most widespread habitat of all the gorilla species. They exist in Cameroon, Central African Republic, Republic of Congo, Angola, Equatorial Guinea and Gabon. They also may live in the Democratic Republic of Congo, but that is unclear. Western lowland gorillas are part of the tropical forest ecosystems of these countries. Like all rainforests, these ecosystems have abundant plant life, which is the sole source of food for these gorillas. There are no predators in these ecosystems, apart from humans, that hunt and feed on western lowland gorillas, or any other gorilla ecosystems.

Sexual dimorphism in Gorillas:

Gorillas are the largest and among the most sexually dimorphic of all extant primates. While gorillas have been incorporated in broad-level comparisons among large-bodied hominoids or in studies of the African apes, comparisons between gorilla subspecies have been rare. During the past decade, however, behavioral, morphological, and molecular data from a number of studies have indicated that the western lowland (Gorilla gorilla gorilla) and eastern mountain (Gorilla gorilla beringei) subspecies differ to a greater extent than has been previously believed. In this study I compare patterns of relative growth of the postcranial skeleton to evaluate whether differences between subspecies result from the differential extension of common patterns of relative growth. In addition, patterns of ontogeny and sexual dimorphism are also examined. Linear skeletal dimensions and skeletal weight were obtained for ontogenetic series of male and female G.g. gorilla (n = 315) and G.g. beringei (n = 38). Bivariate and multivariate methods of analysis were used to test for differences in patterns of relative growth, ontogeny, and sexual dimorphism between sexes of each subspecies and in same-sex comparisons between subspecies. Results indicate males and females of both subspecies are ontogenetically scaled for postcranial proportions and that females undergo an earlier skeletal growth spurt compared to males. However, results also indicate that the onset of the female growth spurt occurs at different dental stages in lowland and mountain gorillas and that mountain gorillas may be characterized by higher rates of growth. Finally, data demonstrate lowland and mountain gorilla females do not differ significantly in adult body size, but mountain gorilla males are significantly larger than lowland gorilla males, suggesting mountain gorillas are characterized by a higher degree of sexual dimorphism in body size. Thus, although lowland and mountain gorillas do not appear to have evolved novel adaptations of the postcranium which correlate with differences in locomotor behavior, the present investigation establishes subspecies differences in ontogeny and sexual dimorphism which may be linked with ecological variation. Specifically, these findings are evaluated in the context of risk aversion models which predict higher growth rates and increased levels of sexual dimorphism in extreme folivores.

e) Why is nonhuman primate extinction of grave concern?

Habitat loss
More than 100,000 people live in the remote areas where mountain gorillas are found. Their need for land to cultivate has reduced the forest in which the gorillas live to virtual islands in the middle of expanding human settlements.

Between 1990 and 1994, large numbers of Rwandan refugees fled to camps at the edge of the Virunga National Park, leading to uncontrolled firewood harvesting as well as increased poaching.

In 2004, 1,500 hectares of prime mountain gorilla habitat were cleared by illegal settlers in Virunga National Park, Democratic Republic of Congo (DRC), according to evidence uncovered by the Congolese Institute for the Conservation of Nature, one of WWF's partners. Convoys of people from Rwanda and DRC destroyed large tracts of the park, home to mountain gorillas and other endangered species, to create agricultural and pastoral land.

Hunting
In addition to being hunted for meat, mountain gorillas are also illegally hunted for trophies and live infants.

As many as 15 of Virunga's mountain gorillas may have been killed since the outbreak of civil war in 1990. Between 1990 and 1994, when large numbers of Rwandan refugees fled to camps at the edge of the Virunga National Park, 4 habituated silverback gorillas were killed, along with some of their group members.

In 2007, a further 7 gorillas were killed.

Oil & gas exploration
European oil and gas companies have been granted exploration consessions in Virunga National Park, home to Democratic Republic of the Congo's mountain gorilla population. While gorilla habitat does not currently fall within an oil concession, development in the park could negatively affect the animals' security.

War & instability
Although the refugees left the camps around Virunga National Park in 1996, continued civil unrest and the presence of armed militias makes survey and conservation work difficult in the DRC's protected areas, which are now in rebel-held territory.

Disease
As more people move into their habitat, and more tourists come to see them, mountain gorillasare becoming increasingly exposed to a variety of human ailments.