1.2 Unifying Themes of Biology
LEQ: What is the relationship between adaptation and
natural selection?
• Assignment: Reading 1.1-1.3
– Focus on: characteristics of life, themes of
biology, hypotheses
• Activator:..entangled bank..
– React to the following quote from Charles
Darwin’s book On the Origin of Species. What
are your views on the evolution of life?
• Key terms: evolution, adaptation
1.2 Unifying Themes of Biology
Evolution is change in living things over time.
• Change:
– genetic information
– anatomy
– development
• Compare and contrast white oak (left) and red oak leaves
(right)
1.2 Unifying Themes of Biology
Evolution can occur through natural selection
• Natural selection
– advantageous traits
– survival
– reproductive success
• Q: What environmental
conditions favor the growth of
evergreens more than deciduous
trees?
1.2 Unifying Themes of Biology
Adaptation involves changes in the traits of species
• Top: coastal live oak
– Close relative of red oaks
• Bottom: southern live oak
– Close relative of white
oaks
• Evergreen: adapting to
poorer growing conditions
– dryness
– salt
– sandy soils
1.2 Unifying Themes of Biology
• New species can emerge when adaptive traits are
passed on to future generations
• Q: What are the characteristics of a tree?
1.2 Unifying Themes of Biology
Adaptation: “racing for the sky” on islands
• Prickly pear cactuses have evolved tree forms on the
Galapagos Islands
1.2 Unifying Themes of Biology
Adaptation: “racing for the sky” on islands
• Cucumber plant relatives have evolved a tree form on
Socotra
1.2 Unifying Themes of Biology
Summary:
• What is the relationship between evolution and natural
selection?
• Speculate:
– Why have so many different types of tall woody plants
evolved?
– Why have so many different types of evergreens
evolved?
1.2 Unifying Themes of Biology
Summary:
• How is the structure of a system (bone) related to how it
functions?
• Reflection: “No organ is an island” ~ Gerard Karsenty. In
what way or for what reason would a bone need to be
attuned to the rest of the body?
• Closing: Describe how our class could be considered a
system.
1.2 Unifying Themes of Biology
Purple praying mantis: note the petal-like anatomy
1.2 Unifying Themes of Biology
Orchids & predators
1.2 Unifying Themes of Biology
1.2 Unifying Themes of Biology
Spiny Flower Mantis
1.2 Unifying Themes of Biology