ANTH 201 Midterm 2 - UofC

ANTH 201 (Winter 2025) - UofC

LECTURE 9: INTRO TO PRIMATES

What are the key mammalian synapomorphies (shared traits) of primates? (3)

• Warm-Blooded

• Viviparity

• Lactation & Mammary Glands

Are the key mammalian traits unique to primates?

No, these traits are primitive for primates and shared with all other mammals

Where are nonhuman primates primarily found? (6)

Mostly in tropical areas

• Central & South America

• Sub-Saharan Africa

• Mediterranean Africa and Saudi Arabia

• Madagascar

• Tropical Asia

• Japan

What are the four main characteristics of primates? (4)

1. Grasping Hands & Feet

2. Sensory System

3. Large Complex Brains & Associated Behaviour

4. Dental specializations, but generalized skeleton

Characteristics: Grasping Hands & Feet (5)

• Opposable thumb and hallux (big toe)

• Nails, not claws

• Sensitive tactile pads

• Power Grip

• Precision grip

What is an opposable thumb and hallux?

The opposable thumb (on the hand) and hallux (big toe) allow primates to grasp objects and manipulate them with precision

What are the two types of grips primates use? (2)

• Power Grip: Strong grip using fingers and palm (i.e. holding a tennis racket)

• Precision Grip: Fine control using fingertips (i.e. picking up a grape)

Characteristics: Sensory System (3)

• Forward facing eyes

• Greater reliance on vision

• Colour vision

What type of vision do primates have?

Forward-facing eyes that allow for stereoscopic vision (both eyes focus together) and depth perception (judging distances accurately)

Why is vision more important than smell for primates?

Primates rely more on vision than olfaction (smell), leading to larger visual brain centers and improved color vision

What types of colour vision do primates have? (2)

• Dichromatic vision (sees blue and green, common in some primates)

• Trichromatic vision (sees red, blue, and green, found in many higher primates like humans)

What structure do all primates have to protect their eyes?

A postorbital bar (a bony ring around the eye socket for support and protection)

What additional eye protection do higher primates (haplorhines) have?

Postorbital closure (a full bony wall behind the eye socket, providing extra protection)

How does primate eye protection compare to other mammals?

Non-primate mammals typically only have a postorbital process (a small ridge of bone instead of a full bar or closure)

What physical changes reflect the reduced importance of smell in primates? (2)

• Shorter snouts (except in some species)

• Smaller olfactory centers in the brain

Do all primates have the same level of olfactory reduction?

No, some strepsirrhines (like lemurs and lorises) still have a strong sense of smell

How do primate brains compare to other mammals relative to body size?

Primate brains are about 2x larger than those of other mammals their size, and human brains are 7-8x larger

What feature increases the brain’s surface area in primates?

Sulci and fissures (folds in the brain) help increase surface area for more neural connections

Characteristics: Large & Complex Brains (3)

• Large brains relative to body size

• Learning & socialization very important for survival

• Greater reliance on learning linked to reduction in reliance upon instinct

Why is learning important for primates?

Learning and socialization are crucial for survival, as primates rely less on instinct and more on experience

How does primate reproduction differ from many other mammals? (2)

• Primates have fewer offspring but invest more time and care in raising them

• Greater lifespan, and usually birth one young at a time

What does “altricial” mean, and how does it apply to primate infants?

Altricial means “requiring nourishment” — primates are born helpless and dependent on parental care

Why do primate infants cling to their mothers?

They have grasping hands and are carried rather than being left in nests (more parental care)

What is juvenescence, and how does it differ in primates?

Juvenescence refers to the long juvenile development period, which allows for extended learning and socialization

What is a dental formula?

A shorthand way to represent the number of each type of tooth in a primate’s mouth (incisors, canines, premolars, molars)

What is the ancestral mammal dental formula?

3.1.4.3

What is the dental formula for primitive primates (strepsirrhines, platyrrhini & most New World monkeys)?

2.1.3.3

What is the dental formula for later primates (catarhinni, Old World monkeys, apes, and humans)?

2.1.2.3

How many teeth does a chimpanzee have with the 2.1.2.3 formula?

32 teeth in total

What type of teeth do folivorous (leaf-eating) primates have?

High-cusped molars for grinding tough plant material (e.g., colobus monkeys, gorillas)

What type of teeth do frugivorous (fruit-eating) primates have?

Broad, flat incisors for biting into fruit (e.g., many New World monkeys)

How does the primate skeleton compare to other mammals, and why is it beneficial? (2)

• Primates have a generalized, flexible skeleton that allows for a wide range of movement

• It allows primates to be adaptable, supporting activities like climbing, leaping, running, and brachiation

What are the two major groups within the primate order? (2)

• Strepsirrhines (Lemurs, Lorises, Galagos)

• Haplorhines (Tarsiers, Monkeys, Apes, Humans)

What is the hierarchical structure of taxonomic classification? (7 levels)

Kingdom —> Phylum —> Class —> Order —> Family —> Genus —> Species

What is the full taxonomic classification of humans?

Animalia —> Chordata —> Mammalia —> Primates —> Hominidae —> Homo —> sapiens

What are the key characteristics of Strepsirrhines? (5)

• More reliance on olfaction (sense of smell)

• Nocturnal in many species

• Postorbital bar instead of full eye socket closure

• Smaller brain size relative to body compared to Haplorhines

• Dental comb & grooming claw

What are the key characteristics of Haplorhines? (5)

• Greater reliance on vision (flatter faces, shorter snouts)

• Larger, more complex brains

• Postorbital closure (full bony protection around the eye)

• Diurnal (except tarsiers & owl monkeys)

• More social and increased parental care

What is a dental comb, and what is it used for?

A specialized arrangement of forward-tilted lower incisors and canines, used for grooming and feeding

What is a grooming claw, and where is it found?

A specialized claw on the second toe of Strepsirrhines, used for personal grooming

What are Strepsirrhines divided into? (2)

• Lemuriformes

• Lorisiformes

Lemuriformes (6)

• Only found on Madagascar & neighbouring Comoros Islands (endemic)

  • Diverse because of endemism and lack of competition → an adaptive radiation

  • Small and medium-sized today

  • Diurnal and nocturnal

  • Female dominance

  • 5 families

Lorisiformes (3)

• All are nocturnal and small bodied

• Generally solitary or in small family units

• Eat insects, gum and nectar, some fruits

What are the two types of Lorisiformes? (2)

• Galagidae

• Lorisidae

Galagidae (3)

• very active

• fast movers

• Africa only

Lorisidae (3)

• often immobile

• slow movers

• Africa and Asia

Enigmatic Tarsiers (4)

• Infraorder Tarsiiformes

• Only one living genus (Tarsius)

• Retain primitive morphology

• Looks like strepsirrhines, but genetically found to be haplorrhines
  

“Higher primates” can be classified together as

Anthropoidea (Platyrrhini & Catarrhini)

Characteristics of Haplorhini: Platyrrhini (6)

• All have tails (several have prehensile tails)

• All arboreal (live in trees)

• Smaller body size than cercopithecoid monkeys

• 2.1.3.3 dental formula

• Minimal sexual dimorphism

• Diurnal (except Aotus - owl monkey)

Prehensile Tail

A prehensile tail is a tail that can grasp or hold objects, acting like a fifth limb

Two Major Subdivisions for Haplorhini: Catarrhine (2)

• Cercopithecoid monkeys (Cercopithecoidea)

• Apes (Hominoidea)

Cercopithecoidea (5)

• Found in a wide variety of environments (tropical Asia, sub-Saharan Africa, North Africa, Arabian Peninsula)

• All diurnal

• Single births

• Some species are terrestrial

• Larger body size, often sexually dimorphic

What are the two subfamilies of Cercopithecoidea? (2)

• Cercopithecinae

• Colobinae

Cercopithecinae (8)

• Fruit eaters

• Broad incisors

• Low cusps

• Cheek pouches

• Simple stomach

• Shorter limbs

• Sexually dimorphic

• Very terrestrial species

Colobinae (6)

• Leaf eaters (specialized folivores)

• Narrow incisors

• High cusps

• No cheek pouches

• Complex sacculated stomach (supports bacteria for digestion of cellulose)

• Long limbs

Hominoidae (8)

• The Apes

• No tails

• Large size and weight

• Larger brain to body weight ratio, advanced cognitive abilities (all show tool use)

• More upright posture

• Longer gestation and maturation

• Suspensory locomotion in trees (NOT brachiation)

• Sexually dimorphic

Lesser Apes: Hylobatidae (7)

• Gibbons and Siamangs

• Southeast Asia

• Monogomous

• Sexually dimorphic

• Frugivores

• Move using brachiation (long strong arms, short legs,
  elongated hook-like fingers)

• Highly territorial (singing calls)

LECTURE 10: PRIMATE ECOLOGY

What does primate ecology focus on?

How primates make a living in their environment and how ecological variables affect social systems

What are the two main concerns for primates? (2)

1. How/what to eat

2. How to avoid being eaten

This influences sociality

Why do organisms need food?

Food provides energy (calories) for growth, survival, and reproduction

What are the four components of total energy requirements? (4)

• Basal metabolism (energy to stay alive at rest)

• Active metabolism (energy used for movement/activity)

• Growth and growth rate (energy for development)

• Reproductive effort (energy for mating, pregnancy, lactation

Basal Metabolic Rate (BMR)

The rate at which an animal uses energy at rest for basic body functions (e.g., maintaining body temperature)

Do larger animals have a higher or lower absolute BMR?

Higher – they use more total energy

Why do larger animals have a relatively lower BMR per unit body weight?

They burn fewer calories per gram of body weight compared to smaller animals

Active Metabolic Rate (AMR)

The extra energy used above the basal rate for daily activities (e.g., movement, digestion)

What factors affect AMR? (2)

• Size of the animal and how far/fast it moves

• For a baboon-sized primate = ~2x BMR

Growth Rate (2)

• Building new tissue requires energy beyond BMR and AMR

• Juveniles/infants have higher energy requirements than predicted for their size (building new tissue)

Reproductive Effort (3)

• Females = additional cost of reproduction

• Late pregnancy = +25% calories

• Lactation = +50% calories

Why do organisms need protein and amino acids?

For growth, reproduction, and bodily functions (since we cannot make all amino acids ourselves)

What macronutrients provide energy?

Fats, oils, and carbohydrates

Why are trace vitamins and minerals important?

They support physiological functions, like iron and copper for hemoglobin synthesis

What are secondary compounds?

Plant defenses that protect against herbivores

What are two examples of secondary compounds? (2)

• Alkaloids (disrupt cell processes, i.e. caffeine)

• Tannins (reduce digestibility)

Where are secondary compounds most concentrated?

Mature leaves and seeds (lower in fruits, flowers, and new leaves)

What is frugivory?

Eating fruit

What is folivory?

Eating leaves

What is the difference between young and mature leaves?

Young leaves are easier to digest, mature leaves have more cellulose and need adaptations

What is insectivory?

Eating insects

What is the difference between social and solitary insects?

Social insects live in colonies, solitary insects live alone

How do primates get water?

Drinking directly or from food items

What are the two main nutrient types primates rely on?

Protein (P) and carbohydrates (CH)

What are common protein and carbohydrate sources for primates? (2)

• Insects and young leaves (protein)

• Fruit and gum (carbohydrates)

Note: Gum is like sap/resin and eaten by Strepsirrhines

Primate diets are reflected in ____ and ____ morphology

tooth, gut

How does diet relate to body size in primates?

Insectivores < frugivores < folivores, in size

Why do smaller primates eat high-quality food like insects?

They need quick-digesting, energy-rich food due to high BMR

Why can larger primates eat lower-quality food like leaves?

They process food more slowly with longer guts and eat in larger quantities

How does food availability vary in primate habitats?

It can be patchy and unpredictable

Why aren't tropical forests always a reliable food source?

Many species exist, but only some produce edible food, and food availability is seasonal

What factors influence food seasonality in the tropics?

Day length and rainfall

How do primates adapt to food scarcity?

They switch to lower-quality diets or reduce energy use (i.e. torpor in dwarf lemurs)

What are keystone resources?

Fall-back foods during scarce seasons (i.e. figs)

What type of food is most abundant for primates?

Leaves and foliage

What foods are seasonal in availability?

Fruits and flowers

What type of food has the lowest density in the environment?

Small prey like insects and vertebrates

How does food density affect primate movement?

The less dense the food, the farther primates must travel to find it

Range

The geographical area in which a group (not a species) can be found

What is a home range? (2)

• The total area used by a group

• Larger for frugivores

What is a day range? (2)

• The area used by an individual on a daily basis

• Larger for frugivores

What is the relationship between food distribution and territoriality?

Clumped, patchy food is defensible, while evenly distributed food is not