Transcript Ch 3 Lecture

Unit 1 Scientific Approaches
Chapter 3
Evolution
Theory of Evolution
• 1.Variation w/in species
(phys and beh)
• 2.Heredity- genetics
passed down
• 3.Adaptation for survival
• 4.Natural selectionthose who cope best
will survive and pass on
traits to next generation
Isolation and Speciation
• Allopatric speciation:
• Members of same
species separated by
physical barrier
• live in diff environ
• will adapt to survive
there, form niche
• Over time become 2 diff
species
• Adaptive radiation
Breeding
• Individual competitionindividuals breed as fast
as they can
• Fitness- combo of phys
and behavior traits help
organism survive and
reproduce
• Sexual selection- diff
traits by gender
maximize their
reproductive success
2 types of evolution
• 1. Slow
• Takes millions of years,
gradual
• 2. Fast
• Punctuated equilibrium
• Pop stays stable and
then changes rapidly
(10,000 yrs) due to
sudden environ
changes
Convergent Evolution
• Convergent- diff
species evolve similar
solutions and resemble
each other w/o being
genetically related
• Analogous structuressimilar in appearance
but different
evolutionary origin
Divergent evolution
• Species w/common
ancestor evolve diff
structures from a similar
original structure
• Homologous structuresdiff fxn but similar
evolutionary origin
• Vestigial organs- parts
of body retained but no
current fxn
Vestigial Organs in Humans
Evolution as fact
Fossil Record
DNA similarities
Homologous structurescommon structure and
physiology
Progressivism Fallacy
• Evolution does not
always go from
simple to more
complex
• Natural selection is
a principle of local
adaptation, not of
general advance or
progress
Purposivism Fallacy
• Thought that all
nature exists for
humanity’s benefit
• Religion and
philosophy provide
purpose
• Science provides
mechanisms and
principles
Ecology and Evolution
• How survival and
reproduction
succeeds depends
on how the animals
interact w/ environ,
predators, etc