Bio 125 Lecture #2 1/21/16
Announcements:
• Quiz 1 on Tues 1/26 on 1st two lectures
• CF topics due next week
I. Living in Water
A. Benefits & Challenges of living in the ocean
1. Salinity
B. Water properties
1. Unique properties of water
2. Structure of water molecule
C. Benefits & Challenges of living in the ocean (con’t)
2. Temperature
3. Breathing: Dissolved Gases
Challenges for life
in the ocean
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pipeline.
Check your pipeline email
account regularly (or forward
emails to yourself)
www.sbcc.edu/pipeline
Location of class website:
www.biosbcc.net/ocean
Salinity affects organisms
Osmostic conformers:
Cell salt content = external salinity
1. Salinity
Osmotic regulators: control salt content of cells
1
Why is water the
most unique
substance on Earth?
Hydrogen Bonds are important – allow
water molecules to stick together
H
H
O
If hydrogen bonds weren’t there –
water could not stay a fluid
This creates viscosity – affects
marine life
Fig. 3.3
Challenges for life in the ocean
1. Temperature
Photo: Norb Wu
2
Temperature & Organisms
Ectothermic
Body temperature varies with
environment
Temperature & Organisms
Endothermic: warm-blooded
Regulate metabolism in response to T
3. Dissolved Gases:
CO2 O2 N2
Ocean &
atmosphere gas
concentrations
are affected by
each other
Disadvantages:
• Over-cooling dangerous
• Energy intensive must eat a lot
3. Dissolved Gases
• Dissolved gases are required for
life in the ocean
• Water temperature affects gas
solubility
Oxygen
Atmosphere:210 ml/L O2 (21%)
Ocean: 0-8 ml/L O2 (<1%)
• Gases dissolve
more readily in
cold than warm
water
3
Lecture 2 (1/21/16) Study Questions
1. Describe the structure of a cell membrane.
2. What does it mean that cell membranes are
semi-permeable? Which substances can pass
through easily?
3. What is an osmoconformer? Explain why &
when osmosis can be dangerous for them.
4. What is an osmoregulator and why might they
be less common in the ocean than
osmoconformers?
5. List the 3 unique properties of water and
explain why each one is important for life.
Lecture 2 (1/21/16) Study Questions
6. Explain how the density of water changes with
water temperature (why does ice float?)
7. Draw a single water molecule, labeling each
atom and the type of bonds that they form with
each other. Explain why this type of bond
occurs.
8. Water is a polar molecule. What does that
mean and why does it occur?
Include the charges of each part of the water
molecule on your diagram of a water molecule
Lecture 2 (1/21/16) Study Questions
9. Explain why water is viscous and how this can be
a benefit and a challenge for marine life.
10. What is an endotherm? List 1 benefit and 1
limitation for them.
11. How does the fact that water has a high heat
capacity impact organisms living in the ocean
compared to terrestrial organisms?
12. Will polar or tropical waters tend to have higher
oxygen levels? Why?
13. Vocabulary list: atom, element, molecule, proton,
electron, valence shell, polarity, covalent bond,
hydrogen bond, viscosity, lipid bi-layer,
osmoconformer, osmoregulator, heat capacity,,
ecotherm, endotherm
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