Human Evolution Exam 2

A gradual change in some phenotypic characteristics from one population to the next

Incredibly related (99.9%) to every other human on the planet due to continuous gene flow.

Fertilized ovum multiples into millions of cells eventual emergence of tissue types, organs and physiological systems. Most vulnerable environmental period of life.

Fetus mostly grows longer.

Rapid weight growth and organ development

agents that can inflict disruption insults, and deformities during development.

produces an anti-herbivory chemical that blocks Shh signaling

also known as sonic hedgehog syndrome it divides optic field by suppressing Pax6 expression in the center of the neural tube.

each of the postnatal periods has a different growth velocity

2 incisors -1 canine -2 molars -3 premolars

walking and running generally develop in first two years.

rapid growth rate of the brain

6 years old

baby teeth

two sets of teeth in our lives.

Wear and tear on teeth

Fetal brain is relatively smooth. By 40 weeks, you develop the wrinkles you will have for the rest of your life.

by 6 years old

11 weeks

flatlines after age 2

Humans continue absolute growth during childhood

48-68% of adult size

36-46% of adult size

25-29%

poor sanitation causes average heights to decrease.

Ends of bones, separate growth. Common in long bones.

Shaft or central portion of the (long) bone

Areas of growth between bones. Filled with cartilage then eventually filled with bone

Yes, bones are very vascular and cartilage is relatively avascular

Reduces the number of oxygen molecules, hypoxia becomes an issue

When body tissues receive insufficient amounts of oxygen.

leads to motion sickness, headaches, nausea, loss of appetite, fatigue, and breathlessness during physical activity; 8,000 ft during rest). (severity and risks increase as a person moves higher)

can impede normal bone growth as it is strongly affected by the environment (nutrition -[not much grows on mountains] and general health.)

-Larger chest cavities than low altitude people

- Restricted growth so generally shorter

- Larger lungs and better lung function

Selection: Alleles for high oxygen saturation in their hemoglobin

- More oxygen = better survival = better reproduction = Natural selection

- Much more resilient to hypoxic impacts

Prenatal and postnatal males appear to be more sensitive to environmental insult than females

Principle that animal size is often heat-related.

- Animals adapted to hot environments tend to have less body mass.

- Animals adapted to cold environments tend to have greater body mass

Warm-blooded animals. we produce internal heat simply by living

Body temp is higher than normal range, loss of function and death.

Increase blood vessel diameter near the body's surface. This is a way of getting more blood to the surface so it can cool before going back to the core of the body.

a physiological response to release heat. Humans have an abundance of eccrine glands to produce sweat.

Principle that some animal's limb lengths are heat related.

- arms/legs tend to be longer in hot environments

- arms/legs tend to be shorter in cold environments

Vasoconstriction

Shivering

Elevated BMR

Clothing and shelter

Decrease blood vessel diameter. This increases blood flow back to the core of the body to produce more heat.

nearer to the equator and in high elevations

away form the equator and in lower elevations

a pigment called melanin

Browns to black skin tone, variations in this largely dictate skin/hair pigmentation/coloration

Pink to red hues (lips, nipples, hair, etc.)

Found in brain. Function unresolved.

Prevents a large number of neural tube defects (NTD). Important in spermatogenesis, reduce heart defects in fetus, reduce stroke risk, DNA synthesis and repair, etc.

a hormone that increases calcium absorption of the small intestine and thus makes calcium available for building bones.

not enough vitamin D synthesis because low light conditions and so much melanin that synthesis becomes difficult

Modern Treatment is Vitamin D supplementation

higher skin cancer risk due to especially high UV. Lose too much folate because skin is not dark enough to protect it.

modern Treatment: Sunscreen/covered skin; Folate supplementation.

a group of closely related and arboreally adapted mammals that live largely in the tropics. they display remarkable dietary plasticity and parental investment

Lemurs, lorises, galagos, pottos.

- They have a post-orbital bar

- Many are nocturnal and some diurnal

- Some have nail and tooth adaptations for grooming

- Mostly see in black and white with the tapetum lucidum in the eye (allows for night vision)

- retain strong olfaction

P.O. Septum: Bony cup, fully closed

P.O. Bar: Partially closed

P.O Process: Incomplete closure

Found in Madagascar

21% of all primate Genera

Most are highly social

Dominant female

Diet of leaves and fruits

Some diurnal, some nocturnal

Found in SE Asia, Sri Lanka, Africa

Generally nocturnal

Lack external tail

Primarily insectivores

- Found in Africa (large distribution)

- Nocturnal

- Primarily insectivorous... but also fruit and small animals

- Common social group: female and offspring

- Excellent jumpers

Found in West/Central Africa

Nocturnal

Nearly exclusively arboreal

Diet=fruit, gums, insects

Includes NWM, OWM, Apes, and Humans

- Larger brains

- Greater sexual dimorphism

- Fewer teeth

- Orbit = full bony septum aka "Post-orbtial septum"

- Fully convergent eyes

- Many have color vision, Most diurnal

- lack a tapetum lucidum in the eye.

Most Strepsirhhines - 2.1.3.3

NWM: 2.1.3.3

OWM, Apes, and Humans: 2.1.2.3

Trait shared due to its presence in a common ancestor

Derived Trait

- Found in the Americas (central and south)

- Some have prehensile tails

- 2.1.3.3 or 2.1.3.2. dental formula. 1 more premolar than we have

- Folivory (leaf diet), frugivory (fruit diet), and insectivory.

- Found across the "old world"

- Approx. 22+ Genera 132+ species

- Colobines ("leaf eating"*, arboreal*)

- Colobus, Langurs, Proboscis

- "Sacculated Stomachs", reduced or absent thumbs.

- Cercopithecines (cheek pouch, monkeys, arboreal and terrestrial)

- Mandrills, baboons, vervets, etc.

- "Ischial Callosities"

- 2.1.2.3 dental formula

Cercopithecoids, Hominoids

found in Cercopithecines. They are hypothesized to function to

1. Reduce Competition with members of their own species

2. Predator Risk Avoidance

3. Storing Food, Resource Distribution.

an extra layer of tissue in the eyes of some vertebrates. Functions to provide the light-sensitive retinal cells with a second opportunity for photon-photoreceptor stimulation, thereby enhancing visual sensitivity at low light levels. (causes eye shine in photos)

Y-5 (Humans, Orangutans, Chimpanzee, Gibbons), Bilophodont (Colobus Monkey)

A form of locomotion where an animal can fling themselves from tree limb to tree limb. Gibbons and Siamangs have long arms and curved fingers that help them do this.

the larger apes such as chimpanzees, orangutans, and gorillas

each group appears to have evolved knuckle walking independently and that each has a slightly different form of locomotion.

- Range: Largest distribution range of all modern (extant) apes

- Shares - 98-99% DNA with chimps

- Terrestrial Quadrupedalism: Knuckle-walking

- Habitat: Tropical, forest savanna, montane forest

Also called Pygmy Chimpanzees, they can not be distinguished from common apes by size alone.

Largest apes, We share - 98% DNA with gorillas. Capable suspensory locomotion but large size dictates terrestrial use. Knuckle-walking

Habitat: Tropical forests, volcanic mountains.

- Mobile joints, Clavicles

- Opposable Thumbs: can touch each of the four fingertips. Enables grasping

- Hands and feet have dexterity: Arboreal adaptation

Especially apes and humans: Precision and power grips

Non-human primates = Abducted big toe (hallux)

Human = Adducted big toe (hallux)

Cutting, shearing food. *Flat, shovel-like

Pierce, tear food *cuspid (one cusp/point), pointed

tear and crush *bicuspid (two cusps)

Chew, crush, grind *four cusps

Apes have enlarged canines, with an upper canine-lower premolar sectorial (cutting, honing) complex

all species of primates and koalas (for some reason)

-forward-facing eyes

- binocular vision aids in depth perception

- Color vision in Apes, humans, OWM

Primates trend toward more convergent orbits while other animals tend to trend toward divergent orbits

Increased Parental Investment

Enhanced touch with dermal ridges for better gripping and sensitivity.

1 in 64 million

Primates have undergone selection for increased vision but olfactory reduction.

- Olfactory bulb reduced

- Occipital lobe increased

Human conchae: Comparatively less surface area. Otter and Dog turbinate network: Complex, high surface area.

- Positive: selectoin for greater visual acuity

- Negative: selection for olfaction

- Positive: Selection for greater tactile acuity (enhanced sense of touch)

- Hearing: generally in line with other mammals per size group

Tarsiers: 2.1.3.3

Lemurs: 2.1.3.3

Lorises : 2.1.3.3

New World Monkeys: 2.1.3.2 or 2.1.3.3

Old World Monkeys: 2.1.2.3

Apes and Humans: 2.1.2.3

Same tooth type

Different Types of Teeth

True: Incisors, Canines, Premolars, Molars

Canine has become an "Incisiform"

A scientific description of the customs of individuals and cultures

First person to immerse into chimpanzee society in Tazmania. first to discover tool use in chimpanzees and observe the "Four Year War" among them

Rwanda - Mountain Gorillas

- Gorilla social structure

- Practice of infanticide amongst gorillas