Human Evolution exam 4

Mossosaurus

Another victim in the mass extinction event of 65 mya

Qualities of a Mossosaurus

• An enormous carnivorous aquatic reptile of the Late Cretaceous

• the largest were over 50 feet long

• had at least 40 - 50

Conical teeth

typically reptiles. If all teeth are the same shape, the term is ‘homodont,

Heterodont

have several diffrent types of teeth

What size were mammals during the dinsoaur period?

They were very tiny less than a pound

Hypothesis for the origin of Primates:

1). Arboreal Adaptation

2). Visual Predictions

3). Angiosperm Radiation

Arboreal Adaptation

Life in the trees in very 3 dimensional:

• Forward facing eyes are necessary for stereoscopic vision. Must be able to judge distance accurately when leaping.

• Grasping hands and feet are important for climbing.

• Nails instead of claws allow tactile pads touch substrate.

Visual Predictions

Ideas behind the thinking: Are squirrels good at getting around in the trees?

• Animals that are good predators have forward- facing eyes

• Depth perception for judging distances of insect prey

• grasping hands to grab prey

• early primates may have evolved in the bushy undergrowth

Angiosperm Radiation hypothosis ( Sussman)

Angiosperm are flowering plants and flowers have nectar and pollen.

• Flowering plants make fruits and nuts

What is Color vision good for?

For being able to tell when fruit is ripe

Pleistocene

Humans first use and control fire in temperate zone

Pliocene

Age of Australopithecus ( many specices) later homo apperes

Miocene

First apes and later first hominins

Oligocene

Catarrahines and Platyrrhines seperateb

Eocone

First true primates ( looked like todays

What was the climate of diffrent Paleocene?

Tropical Forestshad a much greater extent. Even North America and Eurasia ( Which were connected then) had tropical forests

Early primates evolved in the habitat from a small mammal.

How long have primates been around for?

Primates have been around for at least 60 my.

• The earliest primate-like ones are from a time period called the Paleocone

Paleocene

The Pleasiadapiforms were primate-like mammals but they are automaically miore primitiave that any living primate. They lacked a postorbital bar, their eyes were not convergent and many had large, rodent-like lower incisior. NOT TRUE PRIMATES.

Purgatorios

a genus if pleasiadapiform that has less spiky teeth. It is generalized enough to have given rise to the first clear…..

Where is the strongest evidenc e for the origin of primates in

North Africa

What do early primates have?

• Forward facing eyes

• postorbital bars

• grasping big toes

• nails on most digits instead of claws

Eocene Euprimates

The first true primates

Adapids

• Diurnal

• sexuallt dimorphic

Adaptive Radation

The diverse adaptations among the descendants of a single form

Earliest Haplorhines

Archicebus

• 55 mya

• small, diurnal, arboreal, insectivores

Basal anthropoids

Eosimias

• China; 42 miilion years old

• teeth anthropoid-like

• short heel

Early Anthropids Evolve and Thrive

• Oligocene cooling

• Fayum, Egypt ( 29-37 mya)

• tropical environment