The Appearance of New Species - Essay Example

An Introduction to Biological Anthropology What mechanisms lead to the appearance of new species? Illustrate your answer with an example. The mechanisms that lead to appearance of new species include genetic drift, natural selection and mutation. Genetic drift is the change of allele frequency due to random sampling such as natural disasters and not adaptive or environmental pressures. A good example is a male gorilla that mates to produce more offspring not because he is stronger, but because he is closer to the female that is ready to mate. Natural selection is the mechanism where animals in their natural environment change over time, keeping their beneficial traits while weeding out the non-beneficial traits. A good example is where giraffes with short necks die after short shrubs die out, and after some generations all the giraffes will have long necks. Mutation is the mechanism whereby a DNA gene structure in a species changes with some units being deleted, inserted or re-arranged in such a way that it affects or alters subsequent generations. An example is an albinism genetic anomaly (Wool, 67). 2. (A) Describe and compare cladogenesis and anagenesis. Cladogenesis is the evolution that is brought about by the splitting of a lineage. This is the separation of a gene pool into two or more gene pools. Anagenesis, which is also known as phyletic evolution, is that which occurs within a lineage. It is basically the collective changes that completely alter a species into a new species with different characteristics (Wool, 74). (B) How does the phylogenetic tree that uses “prosimian vs. anthropoid” differ from the cladogram that differentiates “strepsirhine versus haplorhine”. The phylogenetic tree that uses ‘prosimian vs. anthropoid’ is different from the cladogram, which differentiates ‘strepsirhine vs. haplorhine’, in that it shows the ancestors together with the degrees of relationship and the time that the taxa lived contrary to cladograms, which only show the degree of relationship and a hypothetical ancestor (Jurmain et al., 68) 3. (A) ) On a separate sheet make a cladogram by hand for primates that includes groups 1-g and the tarsier (LAST PAGE) (B) Then List 3 shared derived traits (if that many exist) that cladists use to define the common ancestor a) All primates - All primates are social animals. - They have a heterodont dentition and larger brains than other animals relative to their body weights. - They all develop dominant hierarchies limiting aggressions within themselves. b) Strepsirhines - They have longer snouts. - They have a dental comb. -Their eyes are to the side. c) Haplorhines -They have a shorter snout. -They have forward facing eyes. -They have a post orbital partition. d) Tarsier -They have a long hairless tail. -They have large eyes and soft fur. -They have long hind legs. e) Anthropoids -They are adapted to climbing trees using their big toes and thumbs that are separated from the other toes and fingers used for gripping branches.. -They have a rotating shoulder joint. -They have stereoscopic vision. f) Platyrrhines -They have a 2:1:3:3 dental formula -They have a wide nasal septum -They have nostrils opening to the side g) Catarrhini -They have a 2:1:2:3:3 dental formula -They have a narrow nasal septum. -They have nostrils opening downwards. h) Cercopithecoidea -They have a pronograde posture utilizing their tails for balance -They move in a quadrapedal locomotion. -Their molar teeth are patterned in a unique bilophodont cusp. i) Hominoidea -they have no external tail. -they have short legs and long arms. -their arms are on the sides (Wheeler, 20-60) 4. Give an example of one primate species that belongs to each of the following clades, then explain where it leaves (Australia etc…), and something interesting about it a ) Lemur A good example of this is propithecus diadema, also known as diademed sifaka. It is found in Madagascar. Its adaptation for grooming is what makes it special from other lemurs. It has a toothcomb and a toilet claw in its second toe mainly for grooming. b) Loris The slender loris found in India and Sri Lanka has a pointed muzzle, long, slender limbs and small hands. It feeds on ants and is mostly solitary. c) Tarsier An example of this is the Philippine tarsier, which is one of the smallest primates. These tarsiers are the only entirely carnivorous primates. They feed on insects, snakes, birds, bats and lizards. d) Platyrrhine The white-headed capuchin, which is a new world monkey found in Central and South America, is in the family of platyrrhines. This type of capuchin is special in the fact that it is dominated by both an alpha female and an alpha male. e) Cercopithecoidea The Zanzibar red colobus found in the main island of Zanzibar, Unguja, is a good example of primates in this clade. The males of the Zanzibar red colobus are very social and defend their group in unison and even groom each other between meals. f) Ape (hominoidea) The gibbons are among the most endangered primates on earth and they fall under this group. Mostly found in South East Asia, the gibbons are known to be very acrobatic regardless of their diminutive body sizes. (Wheeler, 48-69). 5. A) What advantages and disadvantages do primates gain from living in groups? The advantages gained by primates living in groups include cooperative food collection, security in terms of alerting others in case of danger or facing enemies together, and sleeping close to each other to conserve warmth. The disadvantages include the dangers of disease and parasite spread in case of an outbreak and the greater competition for mates, water, food and sites for resting and sleeping (Redmond and Godall, 26). B) Primates have evolved a number of different social organizations, in your own words define and discuss each of the following social categories and then for each category give an example of one primate species (different from those used in your answers above) whose social organization falls into that category and discuss something interesting about that species social life. a) Solitary (noyau)- These are the animals that spend most of their lives in solitude with the exceptions of rearing the young and during courtship and mating. An example of primates whose majority of their lives is spent without the others of their species includes the aye-aye, which is the largest nocturnal primate in the world. They spend their time on the trees from where they eat and mate. b) Monogamy- This is a situation where a male and a female primate copulate and rear their offspring together with no extra pair copulations. It is a case of a nuclear family organization with one father and one mother. A good example are the owl monkeys mostly found in South America, and which are socially monogamous with the males being the parental caregivers carrying the kids and feeding them. They stick to monogamy until one of them dies due to natural circumstances or hostility from the unpaired ones. c) Polyandry- This is where a female primate takes more than one male primate as its mating partner. A good example is the gray mouse lemur from Madagascar whose female benefit from more than one male mate. The female, however, exhibits selective polyandry in that it chooses its suitors. d) Multi-male- This kind of social organization is also known as multi-female. It is where a group of a certain species has more than one mature male and more than one mature female. Most primates fall in this group of organization due to their movement in troops. A good example is the langurs which are found mostly in India. Here they have a holy status and can be very pesky. e) One-male- this social organization is where one male is the alpha to a group of female primates and their immature offspring. A good example is the gelada baboon found only in the highlands of Eritrea and Ethiopia in which one male dominates the whole troop. When there is more than one male gelada baboon in a group, only one of them, the dominant one, mates with the female baboons. f) Fission fusion- This is a form of social organization where the size and composition of the groups change from time to time with the animals forming social groups and regrouping when necessary or in the evening. The chimpanzees fall in this group and will come together during mating or when fruits are ripe in a certain range. g) Hamadryas- This is a patriarchal social organization in which the dominant male controls its group like a leader. A good example is the hamadryas baboon found in the horn of Africa. This species of baboon is so organized in that the male will even punish the female baboons that wander far away from their unit. (Redmond and Godall, 30-50) 6. Based on what we know about the cognitive capabilities of chimps and bonobos (remember the movie “Can chimps talk” including the Kansi experiments by Sue Savage-Rumbaugh, and the M & M experiments with Robbi by Sarah Boysen) - what cognitive and linguistics capabilities would have been present in the last common ancestor of chimps, bonobos and humans? The cognitive and linguistics capabilities that could have been present in the common ancestor of chimps, bonobos and humans include attribution, deception, reciprocal, empathy and pretence. All these are traits found in these species. 7. In her book Goodall discusses how different kinds of mothers and approaches to mothering affect the personality and success of their offspring. Provide three examples from the book about specific mothers (hint – initials F vs P) and their offspring which support Goodall’s position. In Godall’s ‘Through a Window’, readers see how Pom and Fifi who are the daughters to Passion and Flo respectively react to the challenges of life as they grow in the wild. Different kinds of motherhood affect the personality and success in an offspring as is evident when Fifi’s reaction to weaning is not as harsh as Pom’s (40). Fifi recovers quickly from the weaning process and within no time, she is back to her old self. By the time her small brother is born, she is back to being assertive, outgoing and confident. Pom, on the other hand, has a depression that never seems to end. The harsh treatment that she had received as an infant made it almost impossible for her to cope with weaning. Surprisingly, her mother seemed to understand this and even let her suckle her dry mammary glands. Pom is only forced to quit suckling from her mother when her bother Prof was born. Their reactions to their new siblings were also different as Fifi seemed more happy and fascinated by her new sibling than Pom. Pom shows no interest in her brother’s first years in life contrary to Fifi who was even jealous of anyone else playing with her brother. When it was time to mating, Fifi seemed more attractive to the big males than Pom though in their younger years, Pom had radiated more sex appeal. Even their reaction to sex was different as Fifi was more relaxed and calm whereas, Pom crouched before the males and would nervously run away screaming after intercourse (41). 8. A) In several places in her book Goodall discusses the sexual relationships between male and female chimpanzees, and provides several “coming of age” stories. Describe what you learned about the relationship between male and female chimps and how different males approach females and some manage to ensure only they reproduce with them. As a human, how do you feel about the way male chimpanzees treat the females? In Godall’s book (42), one finds out that the male chimpanzees always notice when the females come out of age and are always attracted to the outgoing and calm type. It is evident how they react to Pom’s strange and neurotic behaviors. When she uttered the loud and frenzied pant-barks of submissions, most males were irritated by her to a point of threatening and attacking her. This increased her nervousness, and thus made her a lesser popular sexual partner compared to Fifi. The male chimpanzees would also take the female suitors for expeditions as is the case when Fifi is taken to the outskirts of the community range. This is usually where most kids are sired if the male is capable of keeping the female there for the duration of the females swelling. The male chimpanzees treat the females as special and seem to choose who they will sire their future generations with. The consort male always keeps the other males away from his suitor. B) Is there anything odd sexually about the relationship between baboons and chimpanzees? The baboons are more aggressive to the female during sexual coercion than the chimpanzees since the chimpanzees’ females show no strenuous resistance; hence, are less physically aggressive. 9. Describe the dark times that occurred at Gombe during the early 70s including the “war”, Passion’s weirdness, Gilka and her fate, and the human drama The dark times in Gombe, which started in 1974 all the way to 1978 saw two communities of chimpanzees engage in a conflict. The southern area’s Kasakela and the northern’s Kahama, who were in war, were once a single unit, though Godall’s research showed that they had started their enmity from as early as 1971. She reflects the human life in the chimpanzees’ setting where the mothers are envious of each other’s success in rearing their kids, the horrifying murders, joyous births and wrenching deaths (Goodall 87). 10. How did Figan and Goblin achieve alpha male status in their group? Young adult males, like Figan and Goblin, leave their troops and attempt to get into a new one. If the stranger is stronger and the dominant male is unable to displace the stranger, the dominant male acknowledges the gesture and therefore the stranger becomes the dominant male in the new troop ( Goodall 62). 11. What is your favorite chimp described in the book and why? Provide specific examples about the character and life of that individual. Fifi, being my favorite chimp, shows how being confident assertive and outgoing promises a bright future even in the chimpanzees’ societies. Since she was a little chimp, through her adolescence years and in the way she reared her own kids, including Fiossi and Fanni, she shows the characters and traits of a confident and happy primate (Goodall 9-15; 40-42). Work Cited Goodall, Jane. Through a Window: My Thirty Years with the Chimpanzees of Gombe. Boston: Houghton Mifflin, 1990. Print. Wool, David. The Driving Forces of Evolution: Genetic Processes in Populations. Enfield, NH: Science Publishers, 2006. Print. Jurmain, Robert, Lynn Kilgore, and Wenda Trevathan. Introduction to Physical Anthropology. Belmont, CA: Thomson Wadsworth, 2008. Print. Wheeler, Ward. Systematics: A Course of Lectures. Chichester, West Sussex: Wiley-Blackwell, 2012. Print. Redmond, Ian, and Jane Goodall. Primates of the World. London: New Holland Publishers, 2008. Print. Read More