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Taxonomy - science of classification and nomenclature
Carolus Linnaeus created the two-part naming system called binomial nomenclature.
The binomial consists of the genus
name and the species
name. The genus name is always capitalized and species is not. Both should be underlined or italicized.
Groups at any level may be referred to as a taxon.
Example: Humans are classified as Homo sapiens
, Lions are Pantera Leo
a system that indicates the evolutionary relationships among the organisms under consideration is considered superior to just grouping organisms because they look similar to one another.
traits shared among organisms because they have a common adaptation, but not a recent common ancestor, and arise as a result of convergent evolution. Analogous traits should be avoided when classifying organisms in a scientific context.
Example: common adaptations between sharks and dolphins share a streamlined body
These traits are shared by organisms because they have a recent common ancestor (that is, they inherited the traits from their ancestors)
is a method of classification which places organisms into evolutionary clades.
A clade or branch consists of an ancestral organism and its descendents
Based on shared, derived characteristics.
Discount change along a lineage and are interested primarily in branching events or cladogenesis.
places importance on change that may occur along a lineage over time.
Believe that species change slowly over time through the process of anagenesis.
defined by biologist Ernst Mayr, as a group of potentially interbreeding organisms in nature that are capable of having fertile offspring.
All primates have grasping hands, large brains, and an emphasis on learned behavior.
Primates can be separated from other mammals by a suite of traits that they share in common. The traits may be grouped into two clusters: Anatomical traits and behavioral or life history traits.
Anatomical traits shared by primates
emphasized the importance of vision, excellent grasping ability
- Five digits
- Prehensility (grasping ability) w/ opposability
- Nails instead of claws
- Emphasis on vision
- Generalized dental pattern
- Reduction of the snout
- Enclosed eye orbits
Behavioral traits or life-history traits
shared by the primates emphasize these characters and include the following:
- Single offspring for most
- Extended juvenile periods where the child is dependent on the mother
- Large brains
- Dependence on learned behavior
- Strong mother-infant bond
- Large group size where males live with females year-round
The primate order is divided into two suborders.
(lemurs, lorises and the tarsiers) Anthropoidea
(monkeys, apes, and humans)
A more modern classification groups the taxa into
- Strepsirhini (lemurs and lorises)
- Haplorhini (tarsiers, monkeys, apes, and humans)
share the following features:
Longer snout w/ whiskers and a wet nose (rhinarium
), reliance on smell
triangular, high and sharp cusped molars
- mandible that is unfused in the midline
- large, mobile ears
a grooming claw
on the second digit of the foot in many taxa
nocturnality common, w/ associated large eye orbits
for grooming in some, formed by the lower incisors and canines jutting forward
, partial orbital closure
is a haplorhine but also a prosimian.
Despite their size, locomotion, diet and nocturnality, which links them to the strepsirhines, tarsiers do not have many of the anatomical traits described for the lemurs and lorises such as rhinarium or postorbital bar instead they exhibit a partial closure of the eye orbit
Anthropoids (monkeys, ape and humans)
share the following traits:
Generally larger body and brain size
Reduced sense of smell, reduced snot, no rhinarium
Diurnality, small eye orbits w/ complete orbital closure
Square molar teeth w/ flatter cusps
Fused mandible in the midline
The Anthropoidea are divided into three superfamilies
- Ceboidea (New World monkeys
- Cercopithecoidea (Old World monkeys)
- Hominoidea (apes and humans)
Ceboidea (New World monkeys)
Platyrrhini which indicated that their nose is broad and flat w/ widely spaced nostrils (platyrrhine nose)
- All ceboidea are arboreal; all are diurnal, but one, owl monkey.
- Relatively small
- Have three premolars Dental formula of 18.104.22.168
- All have tails some have prehensile tails
Ceboidea into two to four taxonomic families, including the capuchins, the sakis, the howler and spider monkeys, and the marmosets and tamarins.
Cercopithecoidea (Old World monkeys)
all belong to the infraorder catarrhini
, indicating that the nose narrow, w/ nostrils close together pointing downward (catarrine nose
Live Africa & Asia Some live on the ground while others are in arboreal habitats.
- Dental formula 22.214.171.124 2 pre molars
- The molars are called bilophodont because they have a unique design where the cusps form two ridges for shearing leaves
- Tails are never prehensile
- All exhibit ischial callosities - thickened calluses for sitting on their rump/
Some species are sexually dimorphic.
Old World monkeys are separated into two subfamilies.
Cercopithecinae and the Colobinae
- Colobinae semi-chambered stomach for breaking down cellulo in leaves. Inclu. lagurs
- Cercopithecinae inclu., macaques, baboons, guenons, mangabeys, and pata monkeys.
Superfamily within the Anthropoidea is the hominoidea inclu. apes and humans.
much in common w/ cercopithecoids, including catarrhine nose, 126.96.36.199 dental formula and sexual dismorphism.
In apes the thorax is broad from side to side, not deep anteriorly-posteriorly as it is in monkeys.
Apes do not have tails, larger body size, and apes have long arms and shorter legs indicating that all generally use some sort of suspensory (arm-hanging) locomotion
Two ape families Hylobatidae & Pongidae
- Hylobatidae - gibbons and siamangs
- live in the tropical forest of south and southeast asia "lesser apes"
- Pongidae - orangutans, gorillas, chimpanzees and bonobos,
- "greater apes" by body size
Hominidae - human family
four limbs to support the body above the ground or a tree limb.
may be either arboreal (branch runner) or terrestrial. Hands may be held in numerous positions, which are often group specific; on the:
- Palmigrade - palm
- Digitigrade - fingers
- Kunckle-walking - fist or on the middle phalanges. specifically used by African apes.
- Chimpanzees and gorillas have long curved fingers for suspension
Quadrupedal morphology for the prosimians and monkeys includes the following:
- Arms and legs approximately the same length
- Long, flexible lumbar spine
- Usually have a tail for balance and communication
- Deep, not broad thorax
- Scapula located laterally
- Foramen magnum placed posteriorly, near rear of cranium
VCL (vertical clinging and leaping)
body is held in an upright position while the animal grasps onto the vertical trunks of the tree.
The animal moves about by about by using long powerful hind limbs for jumping to another location.
Common in the prosimians, such as the galago and tarsier
Specific morphology to examine among vertical clingers and leapers includes the following:
- long legs
- vertical body postire
- small to medium body size
involves supporting the body using the forelimbs to hang beneath a tree branch. Thus the body is supported under the arms.
The animal moves about by a hand-over-hand grip, of "arm swinging"
Suspension can be divided into three types:
- exhibited only by the hylobatidae
traditional arm swinging and is very fast
- seen in both New and Old World monkeys, combination of arm swinging and leaping (New World - have a prehensile tail to assist)
- witnessed in great apes, involves a slower form of locomotion. Combination of climbing and swinging is utilized. The orangutan is famous for quadrumanual locomotion "four-handed"
Specific morphological traits for suspension include the following:
- longer upper limbs, including fingers
- short thumbs in the hylobatids for a hook like hand grip
- short, stable lumbar spine
- no tail
- large body size, especially the slow climbers
- broad thorax, not deep
- scapula on dorsum of body
- foramen magnum in intermediate location
involves standing and moving on the two hind limbs. The weight of the body is supported on the hind limbs at all times and is above a firm terrestial support, the ground.
- Morphology that is specific to human bipeds:
- longer legs
- cranium balanced on a vertical trunk
- broad thorax
- scapula on dorsum of body
- foramen magnum centrally located under cranium
- big toe in line with other toes (nondivergent)
indicated a difference between males and females
Some species may exhibit differences in over all body size, tooth size, feather color, tail length, and so on.
Difference may be slight or substantial.
In sexually dimorphic primates, males tend to be overall larger in body mass, larger canine teeth and a prominent sagittal crest.
Solitary: adult females occupy a territory alone with their dependent offspring, common among the strepsirhines and orangutans
Monogamy: one adult male and one adult female w/ their dependent offspring common in gibbons and owl monkeys
Polyandry: one adult female and two or three adult males w/ dependent offspring common in marmosets and tamarins
One Male Polyandry: (sometimes two male polyandry) a harem structure w/ one or two adult breeding males w/ several adult females & dependent offspring, common in gorillas, colobus monkeys and hanuman langurs
Multi-Male Polygyny: multiple adult males and females w/ dependent offspring, common in baboons and chimpanzees
Can determine social structure from the teeth, in particular the canine. Large projecting canines are indicative of polygynous groups in which males compete for femals/
Primate Dentition and Diet
Teeth are considered strongly genetically conservative - maintain structure
Molar Cusp Shape
- Dental formulas (incisors, canine, premolars, molars.)
- Old world monkey, apes, humans 188.8.131.52
- New world monkey 184.108.40.206
- Prosimians are variable
- High sharp cusps w/ pointed incisors indicate an insect-eating diet (insectivore)
- Lemurs and lorises - tooth comb
- Monkeys:Crested or rifged cusps for shearing, ina leaf-eating diet (folivore)
- Molars w/ crests are called bilophodont molars. Common in Old World.
- Low, rounded cusps w/ broad, flat incisors indicate a fruit eating diet (frugivore)
- Molars w/ five rounded cusps and a Y-shaped groove between cusps are called Y-5 molars and are found in humans and apes.