BI102 General Biology

Spring 2008

Dr. Brian K. Penney

Goulet 2320

603 641-7149

bpenney@anselm.edu

Brian K. Penney 's web page

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1. Our primate ancestry

   • Features common to all primates include limber joints, grasping hands and feet with opposable digits, face altered for stereoscopic vision and good touch sensitivity.
   • These characters probably originally evolved as adaptations to arboreal life about 65 million years ago.

   • Two major groups of primates:

     • Prosimians are the most basal primates, and are small, arboreal species that move among trees by brachiating. These include lemurs, lorises and tarsiers.

     • Hominoids (= apes) are within the Anthropoids, and generally have higher brain to body weight ratios and rely more on sight than on smell.

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2. Hominids probably evolved from an ancestor common with apes

   • Hominids probably evolved from an ancestor common with apes and chimps about 5-7 mya.

   • The lineage includes Australopithecus, which shows features intermediate between man and other anthropoids

   • The lineage shows evolutionary trends in five major features:

     1. Bipedal posture: upright posture and two-legged walking.

     2. A more juvenile facial shape, such as shorter jaws, flatter faces and more pronounced chins

     3. Increased brain size relative to body mass, with language, symbolic thought and ability for complex tools (occurred AFTER bipedal posture)

     4. Reduced size difference between sexes, probably correlated with a more monogamous lifestyle.

     5. Family structure: increased pair-bonding between mates as well as the period and larger extent of juvenile dependence on parental care.

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3. Genus Homo

   • Genus Homo arose in Africa approximately 2.5 mya, and coexisted with australopithecines and other hominids.

   • Trends in the genus are largely for increased brain size, with a mutation allowing capability for language and reduced sexual dimorphism.

   • Homo sapiens arose in Africa about 150,000 years ago, and subsequently dispersed to other continents, adapting to local environments in such features as skin color. Symbolic thought appears to be one of the great innovations of our species

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4. The role of culture

   The power of culture is the transmission of learned information to new generations. Three major phases of human cultural existence include Scavenging-hunting, Agriculture, and the Machine age.

Copyright 2007-2008, Brian K. Penney

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