Lab Final Study Guide

What is a primitive trait?

What is a primitive trait?

Traits inherited from distant ancestors that are shared across many lineages

What is a derived trait?

Traits that only just appeared (by mutation) in the most recent generation or ancestor

• many only shared among and few closely related lineages

What is a homologous trait?

A trait that is similar between species due to inheritance from a common ancestor

What is an analogous trait?

A trait that is similar between species but is not due to shared ancestry (separate origins)

• separate evolution due to similar selective pressures

what are the primitive traits that are distinct to all primates?

• grasping, opposable big toe

• Nails instead of claws on hands and feet

• Increased reliance on vision (3D vision)

• Decreased reliance on sense of smell

what are the derived traits shared between some primates?

• Postorbital bar or septum

• Larger juvenile development and dependence on parents

• Few infants born at a time (usually 1-2 per birth)

• Enlarged brain relative to body size

• Increased social complexity/organization

Where do Platyrrhines usually live? (NWM, New world monkeys)

Exclusively in Central and South America

Where do Catarrhines usually live? (OWM, Apes and Humans)

Found in Africa and Asia, Humans are found everywhere

How do you identify a Platyrrhine? (NWM)

• nostrils face outward, some have a prehensile tail, arboreal (live in trees)

• Dental formula of 2-1-3-3 or 2-1-3-2 (always has 3 premolars)

how do you identify a Catarrhine? (OWM and Apes + humans)

• Downward directed nostrils, both arboreal and terrestrial (live on land)

• Dental formula: 2-1-2-3, CP3 Complex

• Many species sexual dimorphic (the difference in appearance between males and females of a species)

What are the four main dietary strategies of primates and the characteristics specific to the diets?

• Folivory: diet primarily consists of leaves/foliage with bilophodont molars

• Frugivory: diet of ripe fruit with Y-5 Molars

• Insectivory: insect based diet with pointed cusps on molars

• Gummivory: eat tree gum or sap with precumbent incisors

Folivory

Primarily consists of leaves/foliage

• has bilophodont molars - 4 cusps, each pair connected from left to right by a ridge (used for shearing leaves)

• Altered digestive tracts for processing leaves

Frugivory

Diet of ripe fruit

• has Y-5 molars - 5 cusps with a Y-shaped pattern between them

  • Used for chewing fruit and keeping seeds out of crevices

Insectivory

Insect-based diet

• pointy cusps on molars for processing exoskeletons

• Digestive mechanisms for dealing with toxins from insects

Gummivory

Diet of tree gum or sap

• procumbent incisors for puncturing tree bark, causing them to secrete gum and sap

CP3 Complex

Large upper canines that sharpen themselves on the lower premolars

Locomotion

The movement or ability to move from one place to another

What are the 6 types of primate locomotion?

1. Arboreal quadrupedalism

2. Terrestrial quadrupedalism

3. Vertical clinging and leaping

4. Brachiation

5. Knuckle walking

6. Bipedalism

Arboreal quadrupedalism

Shorter limbs overall, lowers center of gravity closer to the ground so animals can stay stable in trees

• flexible joints in forelimbs and hind limbs

• Ball and socket joints are rounder and shallower

• Large range of motion

Brachiation

When primates swing from tree limb to tree limb using only their arms

• fore-limb dominated (forelimbs are longer than hindlimbs)

Bipedalism

Locomotion using two limbs or legs

While locomotive behavior has fore-limb domination?

Found in Brachiators

What locomotive behavior has hind-limb domination?

Vertical clingers and leapers

Vertical clinging and leaping

Hind-limb dominated (hind limbs are longer than fore limbs)

terrestrial quadrupedialism

An animals that uses four feet or limbs to move

• longer limbs, adaptations for running on the ground

• Stiff joints in forelimbs and hind limbs

• Ball and socket joints are deeper - less motion

• Range of motion is less than 360 degrees

What are the 5 types of primate mating strategies

• inter birth interval

• Natal group

• Reproductive strategies

• Male strategies

• Female strategies

Inter birth interval

The length of time between births

• dependent on time it takes for offspring to mature)

• Usually longer in mammals

Natal Group

The social group that an individual was born into

• females usually stay with their natal groups throughout thier lives while males must move out

Reproductive strategies

Strategies to increase the number of successful offspring

Male strategies

compete for females

Female strategies

Compete for resources

Sexual dimorphism

A physical change or difference between males and females

Which mating strategy has the highest degree of sexual dimorphism?

Polygynous groups (one or more males, multiple males)

• males generally have larger bodies than females

• Males also have larger canines than females (CP3 Complex)

Which mating strategy has the lowest degree of sexual dimorphism?

Monogamous/Solitary primates

• males and females tend to be monomorphic in these groups

What are the core tenets of the Modern Evolutionary Concepts?

• the gene is the basic unit of inheritance

• New genetic variation is created by mutation

• Populations often contain significant variation (individuals within populations are unique)

• Most traits are polygenic meaning they are encoded by more than one gene

• The unit of evolution is the population (individuals don’t evolve, populations do

What is microevolution?

Examining population changes from one generation to generation

What is macroevolution?

Change in allele frequencies over many generations that leads to a new population or species

Which Epoch did primates originate in? What were these primates called?

Palaeocene Epoch (65-54.8 MYA)

• small mammals

During the Eocene, the primate order split into two groups, what were these groups?

Adapoids and Omomyids

Adapoids

A group of primates distributed throughout North America, Europe, Asia, and Africa

• has a post-orbital bar

• They lacked a tooth comb and grooming claw, they likely gave rise to modern Strepsirrhines (Lemurs and Lorises)

Omomyids

Distributed throughout North America, Europe, Asia, and Africa

• large eye orbits and teeth adapted to Insectivory

• May have given rise to modern haplorhines

• Resembled tarsiers and were probably nocturnal

  • Nocturnal eye orbit index

During the Oligocene Epoch, Anthropoids split into 2 more groups, what are these groups?

Platyhines (NWM)

Catarrhines (OWM, Apes, and Humans)

what caused many primates to go extinct at the end of the Eocene/beginning of the Oligocene?

started as one of the warmest climates, ended in cold, dry climate

What is faculative bipedality?

Having the capability to walk or run on two limbs, while also being capable of other modes of locomotion

What is Obligate Bipedality?

Walking or running on two limbs is the main mode of locomotion

What is an S-spine and how is it beneficial to Bipedalism?

It is the spine shape that humans have, it is longer and more flexible

• Spinal Lordosis: s-shaped curvature in the spine, helps with balance over two feet

What was the significance of the discovery of Ardipithecus ramidus (Ardi)?

• they had an abducted (grasping) toe, repositioned gluteal muscles that assisted in the theory of bipedality, as well as flexible hands and wrist

  • It showed transitional evidence that that specimen was capable of walking on tow legs and climbing on trees

What was the significance of the discord of Australopithecus afarensis (Lucy)?

• they had repositioned anterior gluteal muscles like humans, and a pelvis similar to humans, an adducted big toe (derived), they had mild sexual dimorphism (similar to modern humans)

  • This means that by this point in time, our ancestors were probably good biped

What originated first, bipedalism or large brain size?

Bipedalism, the very first bipedal adaptations happened around 6 million years ago, while large brain size wasn’t prominent for another few million years

Gluteus Maximus

Keeps you from falling forward

Gluteus medius

Hip stabilizer, keeps you from falling sideways

Gluteus minimus

Pelvis stabilizer, keeps you from falling sideways

What are the characteristics of gracile Australopithecines (Taung child)

• slenderly built, less facial prognathism (projecting face) relatively small canines

What are the characteristics of Robust Australopithecines?

• robust skull and jaw, very large chewing muscles, facial prognathism (facial projection), large molars and premolars

  • (Ate gritty food, tubers, and grasses, thick enamel)

Who was the first hominid to use tools?

Homo Habilis “Handy Man”

what is the oldest tool technology?

Oldowan Tool Technology (around 2.5 - 1.2 MYA)

• stone flakes, hammers, and choppers

Who was the first hominid to leave Africa?

Homo Erectus (upright man)

what are some characteristics of Homo Erectus (upright man)

• skills are generally long, less facial prognathism, large brow ridges, sagittal keel (point on top of head), modern human limb proportions, smaller dental arcade

  • First hominid to use fire

Which species used Acheulean tools?

Hominid: Homo erectus

What are the important features of Homo Heidelbergensis?

• Large brow ridge

• less prognathism face compared to earlier species

• larger cranial capacity compared to earlier species

• short wide body for dealing with cold climate

what are the important features for Homo Neanderthalensis?

• adaptations fro cold climate during Upper Pleistocene

• Huge nasal passage with nasal turbinates - increases humidity and warm air

• Large infraorbital foramina (holes below the eye orbits) for increased blood flow to the face

• Stocky bodies with shorter limbs - heat retention (Bergman’s and Allen’s rules)

What is Mousterian tool technology?

• from 300 - 30 kya

• They would chip tiny sections of rock away at a time on both sides to make a point

  • More complex than other tool industries, more control over how the tool worked

  • Good hunters, spear tips and projectile points