Download 1.2 Unifying Themes of Biology

1.2 Unifying Themes of Biology
LEQ: How is the structure of a system related to its
function?
• Assignment: Reading 1.1-1.2
– Focus on: characteristics of life, themes of biology
• Activator (In Journal): Values
– “When you get something really small….everything starts
to change. They offer new properties and you end up
making different structures you never thought of before.”
Rich Robinson
– Brainstorm and discuss something in our world that acts as
a system. Describe its parts and unique properties.
• Key terms: system
1.2 Unifying Themes of Biology
Systems of any scale consist of related parts.
• Systems:
– multiple parts
– interacting
– interdependent
– novel properties
1.2 Unifying Themes of Biology
The properties of a system emerge from its parts
• Q: what does each architecture seem suited for?
• Discuss: what are the functions of a skeleton?
1.2 Unifying Themes of Biology
Systems are built from the actions of cells
• System: skeleton
• Cellular
– Osteoclasts “consume”
– Osteoblasts “build”
• Chemical
– Collagen (flexible)
– Calcium phosphate
(brittle, hard)
1.2 Unifying Themes of Biology
1.2 Unifying Themes of Biology
Systems have novel properties
• Bone is:
– Compressible, elastic…tensile?
– Engineered to (micro)crack!
- “stress concentrators”
1.2 Unifying Themes of Biology
Changes in a system can cause dysfunctional structure
• Fibrodysplasia Ossificans Progressiva repairs connective
tissue injuries with bone
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
Summarization
• Describe how your biology class could be considered a
system.
• Choose something from common experience (it helps if it
has parts) and create a general explanation about how it
functions as a system.
1.2 Unifying Themes of Biology
Structure and function are related.
• 2) Structure determines function:
– anatomy: shape suits the task it performs.
– Speculate: what do these cells look like? What do
they do?
1.2 Unifying Themes of Biology
Evolution explains the unity and diversity of life.
• Evolution explains how physical characteristics have
changed in living things over time.
- Adaptive traits (adaptations) are beneficial characteristics
are passed to future generations.
1.2 Unifying Themes of Biology
Warm-up:
• Possible sentences:
– Systems:
– Structure/function:
– Evolution:
1.2 Unifying Themes of Biology
• The essential components for evolution:
– Variation – the characteristics of any species tend to
display a high degree of variability
– Heredity
– Selection – many factors influence how common a
particular variant of a characteristic is.
- Predation, choices made by opposite sex, etc.
– Time – selection operating on a species can change
its DNA and appearance over time
– “Nothing in Biology makes sense except in the light of
evolution.” Theodosius Dobzhansky
1.2 Unifying Themes of Biology
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
• Example: origins of icefish
– No red blood cells
- How do they breath?
– Live at temperatures
below freezing
- Why don’t they freeze?
1.2 Unifying Themes of Biology
• Evolution accounts for both the diversity and the unity of
life. What can these two possibly have in common?
1.2 Unifying Themes of Biology
• Biodiversity is the variety of life.
– Result of evolution: variation + change  diversity!
– generally increases from the poles to the equator.
– Biodiversity and abundance is greater in areas with
consistently warm temperatures.
- Why?
Biodiversity is
greater closer to
the equator.
1.2 Unifying Themes of Biology
Organisms must maintain homeostasis to survive.
• 4) Homeostasis enables an organism to maintain a
unique chemical environment internally while the world
changes around it
• Homeostasis is the maintenance of constant internal
conditions.
1.2 Unifying Themes of Biology
– Homeostasis return a condition to its normal (set)
point.
1.2 Unifying Themes of Biology
Assessment:
• Which of the following themes explains how organisms
change over time:
– A) Structure/function B) Homeostasis C) Evolution D)
Systems
1.2 Unifying Themes of Biology
Summary: answer the following questions in your
journal with your lab group.
• Why is homeostasis essential to living things?
• Do you think homeostasis is necessary inside a cell?
Explain why or why not.
• How are structure and function related to the term
adaptation?