Transcript Evolution Lecture 2

Evolution Lecture 2
Human Evolution
Types of Selection
Classification
Types of Primates
10 Features of Primates
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Five Grasping Digits
Fingernails and Toenails
Fingertips
Ball and Socket Joints
Stereoscopic Vision
Small Nose
Omnivorous
K-Strategist
Large Brain
Social Group
Distinctions Between Humans and
Apes
Trends in Hominid and Human Fossils
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Uncertainties about Human Evolution
Many gaps and questions in human evolution
timelines
Fossil record is incomplete – most bodies are
decomposed and don’t leave behind a fossil
or fossils degenerate over time – as a result,
difficult to determine how different species of
hominid are related
Most hominid fossils are limited to bones and
teeth
Difficult to estimate cranial sizes because of
differences between males, females and
juveniles
In the evolution of hominids, there is a general trend
showing an increase in cranial capacity
Humans have undergone Genetic and Cultural
Evolution
• Genetic evolution – deals with inherited
characteristics:
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o
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Physical characteristics (brain size, bipedalism)
Number of chromosomes
Particularities of biochemicals such as blood
proteins
• Cultural evolution – deals with acquired
knowledge that can be passed within a
social group and through generations:
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o
o
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Language (spoken and written)
Customs and rituals (burying the dead)
Art
Technology (obtaining food, warfare)
Human Classification
• Animalia = Eukaryotic, Multicellular, Motile
• Chordata = Vertebral column
• Mammalia = Mammary glands, sweat
glands, hair
• Primate = Opposable thumbs, stereoscopic
vision
• Hominidae = Bipedal, large brain
• Homo = Flat face, small teeth and jaw
• Sapiens = Language, complex tools
Types of Selection
Stabilizing Selection Curves
Theories of Evolution - Corollaries
• Random genetic drift is the loss of alleles from a
population's gene pool through chance.
• Mutation introduces genetic variation into a breeding
population.
• Gene flow occurs through interbreeding: the
transmission of genetic material from one population to
another. Gene flow decreases differences and inhibits
speciation, the formation of new species.
Homologous Structures
Vestigial Structures
Classification
• http://www.ib.bioninja.com.au/standardlevel/topic-5-ecology-and-evoluti/55classification.html