Life of Primates

What are the four categories of great apes?

Chimpanzees, orangutans, gorillas, and bonobos

How many species of primates are there?

700 species

What is crypsis?

When an animal camouflages itself to blend in with its surroundings (e.x. Indian Leaf Butterfly)

What was interest like in Europe when Darwin published “On the Origin of Species?”

Interest in diversity of life, species = unit of diversity, how do species arise?

What is aposematic coloration?

Colors or patterns that deter predators or signal danger.

What is mimicry?

Some animals will copy coloring of a different species.

What is Batesian Mimicry?

Harmless species mimic aposematic pattern of harmful species

What were Reverend William Paley’s ideas about evolution?

Complex design + function = God. There must be a God because of design and exquisite function. Natural Theology.

Natural Theology

Species are immutable — single creation event after which species do not change. No natural mechanism as opposed to a supernatural mechanism.

What happened in 1836 in relation to Darwin’s study?

Darwin started serious work/thinking on the problem of adaptation.

What happened in 1842 in relation to Darwin’s study?

Formulated the idea of natural selection. Rejected William Paley’s idea. Decided not to tell anyone about his idea. Amassed large amounts of convincing evidence to make the public believe it.

What happened in 1858 in relation to Wallace?

He formulated the idea of natural selection and immediately writes a letter out to tell people

Who did Darwin tell his ideas of natural selection to?

3 people: Charles Lyell

4 Principles of Evolution by Natural Selection *only the fourth principle is from Darwin and Wallace

1. More individuals are born than survive and reproduce. 2. Animals, plants, and organisms of a species have a great deal of variation. 3. The struggle for existence (competition). 4. Variants that are better suited to conditions leave more offspring.

Linneaus coined what term in 1758?

Order primates.

The two characteristics that are most important to define primates:

Vision and hands (+feet)

Characteristics of primate hands and feet

Pentadactyly (5 digits), opposable hallux and/or pollex, prehensile hands and/or feet (able to grasp), volar pads, nails

Characteristics of primate vision

Big eyes and larger visual cortex, olfactory part of brain is smaller, forward facing eyes and shorter distance between eyes (orbital convergence—forward placement of eyes in skull), two visual fields that overlap to some extent (allows for greater depth perception)

Characteristics developed for arboreal life

Depth perception and prehensile hands and feet

Arboreal Life Hypothesis: Purgatorius

Purgatorius: oldest primate fossil. Montana. Small (1oz). 66mya following the Doomsday Asteroid Collision. 100,000-150,000 after asteroid. Flowering plants diversifying—arboreal. Teeth suggested herbivore. Opposable thumbs

Archicebus

55mya. China. Orbital convergence. Opposable pollen & hallux. Prehensile hands and feet. Teeth suggest insect diet.

Predators eyes vs prey eyes

Forward facing vs panoramic vision, side facing, and elongated pupil

Skeletal Trends in primates

Cranial anatomy—bone goes around entire eye (postorbital bar- fusion of two bones). Humans have frontal and zygomatic bone. For stability while chewing. Some primates have postorbital septum — enclosed bony eye socket.

Teeth are generalized and not specialized. This allows for a flexible diet.

Orthograde posture is upright—foramen magnum (hole in skull for brain-spinal cord connection is oriented downward). Bipedalism. Free hands

Hallux vs pollex

Hallux = big toe. Pollex = thumb