Mammals_-_Primates Flashcards
Q: Most advanced group of mammals?
Order Primates
Q: Which order of mammals contains humans?
Order Primates
Q: How long have primates been around?
Fossil record indicates that primates have been around for some 55 million years.
Primates are relative newcomers on our planet.
Q: Connect primate characteristics to their early evolutionary development.
When dinosaurs became extinct (65 mya), new niches opened allowing mammals, including primates, to proliferate.
Earliest primate diverged from primitive arboreal form of insectivore when many placental mammals were in their incipient stages of evolution.
Early ancestors acquired most of their food from the tropical canopy. Natural selection favored traits that enhanced efficiency in foraging and agility in trees. Many primate characteristics represent adaptations to life in an arboreal environment:
-Hands and feet for grasping (Climbed in trees and used their hands to bring food to their mouth).
-Visual acuity with good depth perception and color vision (both important when looking for ripe fruits and young leaves).
-Increased size of cerebral cortex. Cognitive skills enhanced (remembering identity and location of food sources)
-Decline in use of the sense of smell.
Q: Relationship between brain size, instinctive behaviors, and development of primate young
As brain size increases, instinctive behavior decreases and behavior is increasingly directed by experience and conscious decision.
As a result, primate young, with their larger brains, have long periods of dependency during which they learn much of what they will need to know as adults.
Primates depend on learning for survival more than any other group of animals.
Q: Primate characteristics, both physical and behavioral
Highly intelligent. Brains are large relative to body size.
Five digit hands, with various degrees of opposable thumbs.
Ball and socket shoulder and hip joints. Various degrees of increased limb mobility.
Binocular vision. Stereoscopic vision. Forward facing eyes.
Decreased emphasis on olfaction.
Flat nails (instead of claws, for the most part) allow easier manipulation of objects. Highly developed sense of touch.
Complex social groupings where they build and reinforce bonds between individuals.
Learn from mothers and others of their species. Brains continue to develop after birth and into adulthood.
Prolonged infancy and childhoods and long dependency on parent(s). Attentive parental care.
Relatively long lives.
Highly diverse.
Teeth adapted to eating a wide variety of foods.
Q: One key ecological role of primates?
Primates whose diet includes a high proportion of fruits play an important role in the forests as seed dispersers.
Q: Names a part of primate brains that increased in size and one that decreased.
Primate brains have increased areas for vision and reduced areas for olfaction.
Q: Reason for shortened muzzle in primates?
Prevents the nose getting in their visual field.
Q: Two terms describing different features of vision, both of which primates have?
Binocular vision: Vision in which both eyes are used together.
Stereoscopic vision: The single perception of a slightly different image from each eye, resulting in depth perception.
Q: Why is stereoscopic vision useful for primates?
Forest-dwelling primates use it to judge how far away the next branch is as they are moving from tree to tree.
Q: Which animals have flat nails instead of claws? Benefit?
Only primates have flat nails on toes/fingers.
In primates, for the most part, nails replace claws.
Flat nails and accompanying sensitive finger pads are advantageous when when climbing trees and grasping and manipulating objects.
Q: Key features of primate hands/feet
Flat nails and accompanying sensitive finger pads are advantageous when when climbing trees and grasping and manipulating objects.
Very highly developed sense of touch.
Sensitive pads on digits have friction ridges, which are important for grasping. These finger prints are unique to the individual as they are in humans.
Increased thumb mobility (varying degrees, separate card) allowing them to manipulate objects but not all primates have similarly dexterous hands.
Good power grips, but lack the degree of opposition needed for good pincher grip or fine motor skills that humans have.
Grasping feet (except humans).
Q: Key features of primate limbs?
All primates have ball and socket shoulder and hip joints. Allows increased rotation of the limbs, enabling primates to climb easily and quickly in the trees where they find food.
Motion at the shoulder is further enhanced by the clavicle or collarbone.
Q: Discuss the general variation in thumb mobility across different primates.
As you move across the primate order from lemurs to great apes, including humans, the thumb becomes more and more mobile.
Most Old World monkeys, apes, and humans have opposable thumbs.
New World monkeys and prosimians have semi-opposable thumbs.
Humans are the only animals on Earth with fully opposable thumbs; most primate thumbs will only oppose to their index fingers.
Primates have good power grips, but lack the level of opposition that would give them a good pincher grip, or fine motor skills that humans have.
Q: Which primates have grasping feet? Reason for lack thereof?
All except humans.
Human feet are designed for bipedal walking with a more vertical posture than that of the other primates.
Q: Two terms (and definitions) used to describe a key distinction between methods of locomotion of different primates (and other animals)?
Bipedal- using only two legs for walking.
Quadrupedal- using four feet for walking and running.
Q: What part of primates besides fingers has a highly developed sense of touch?
Underside of many prehensile tails.
Q: Opposable thumb
Thumb whose tip can be brought into opposition with the tips of any of the other digits.
Q: Prehensile
Adapted for seizing or grasping, especially by wrapping around.
Q: Describe the first primate-like mammals. Include role in ecosystem.
Insectivores.
Roughly similar to squirrels and tree shrews in size and appearance.
Were adapted to arboreal life.
Probably nocturnal.
Q: Evolutionary progression of primates (geography, competition, physical traits, ecological roles)
-First primate-like mammals were arboreal, nocturnal (probably), insectivores. (more on separate card)
-Flowering plants had evolved and modern looking tropical forests contained a great variety of fruits. Primates became important arboreal seed dispersers and lemurs, with their longer snouts, were pollinators as well.
-Early in primate evolution, prosimians drifted to Madagascar (only primates to successfully make this trip). Evolved into a wide variety of niches over tens of millions of years. No competition from monkeys and apes + few predators => great diversity of lemurs.
-As monkeys evolved from prosimians, they became the dominant primates, and probably caused many prosimian species to go extinct.
-Some early monkeys got to South America by island hopping and rafting, thus becoming isolated, and setting up the population of New World monkeys, who appeared about 30 MYA.
-Eventually, apes evolved from Old World monkeys and displaced them from many environments. (more on separate card)
Q: From which group of primates did apes evolve?
Old World monkeys
Q: Discuss the adaptations involved during the divergence of apes from old world monkeys.
Original ape group diverged from monkey ancestors primarily because they came to exploit more intensively one particular forest food resource, fruit.
Dietary changes led to changes in dentition.
Using arms to swing under the tree branches (thanks to a mobile ball-and-socket shoulder joint) rather than walking on top with all four limbs became a very effective means of acquiring fruit on the outer branches.
Q: Reasons for great diversity of lemurs?
Isolation of population. No competition from monkeys and apes + few predators.
Q: Evolutionary trends involved in progression from less-primitive prosimians->monkeys->apes.
Trend toward enlarged brains with increased areas for vision and reduced areas for olfaction.
Trend toward more vertical posture.
Trend toward different use of forelimbs and hind limbs (for more than just locomotion).
Trend toward longer lives with longer periods of infancy, childhood and adulthood.
Q: How are different primates currently grouped taxonomically?
(note: order > suborder > infraorder > parvorder > superfamily > family)
Order Primates has two extant suborders: Strepsirrhines and Haplorhini.
-Strepsirhine = “moist-nosed”. Includes lemurs, galagos (“bushbabies”), pottos, and lorises.
-Haplorhini = “dry-nosed”. Has two infraorders: Simiiformes and Tarsiiformes.
–Tarsiiformes: tarsiers
–Simiiformes (monkeys and apes) has two parvorders: Catarrhini (old world monkeys) and Platyrrhini (new world monkeys).
—Catarrhini (old world monkeys) includes two extant superfamilies, one of which is Hominoidea, which has two extant families: lesser apes - Gibbons, family Hylobatidae; great apes - family Hominidae.
Q: What are often considered to be the three major groups of non-human primates?
(See separate cards for taxonomy details.)
Prosimians (Strepsirrhines + Tarsiiformes)
Monkeys (Usually considered to be all animals in infraorder Simiiformes EXCEPT the apes.)
Apes (Superfamily Hominoidea within Simiiformes)
Q: What does prosimian mean? Which primates are considered prosimians? Where do these fit into the current primate taxonomy?
Prosimian means “pre monkey” or “before the monkey”.
Prosimians include strepsirrhines (lemurs, galagos (“bushbabies”), pottos, and lorises) and tarsiiformes (tarsiers).
Strepsirrhines is one of the two extant suborders of order primates. The other suborder is Haplorhini, which has two infraorders, one of which is Tarsiiformes. (The other infraorder is Simiiformes, which contains monkeys and apes.)
Q: Key characteristics of prosimians?
More primitive primates.
Pointed or dog-like muzzles.
Larger ears.
Wet noses, except tarsiers.
Semi-opposable thumb.
Stronger sense of smell than most primates. (olfactory brain lobes are larger) Have Jacobson’s organ (VMO).
Flat nails except for a claw for grooming on 2nd toe (+3rd toe in Tarsiers).
Mainly arboreal.
Q: Where do the different groups of prosimians live?
Lemurs found only on Madagascar.
Pottos and bushbabies in Africa.
Lorises and Tarsiers in Asia.
