1
Biology Lecture Notes
Characteristics of Life
1. Complexity
a. Life is complex compared to the background environment
2. Reproduction
a. Life abides by the rule biogenesis - life gives birth to like, life comes from life
b. Before, they thought abiogenesis (life just happening) was a thing. But, Pasteur
proved this wrong by not letting stuff come in and lay eggs on rotten meat
c. BUT - in the beginning, some think life sprung about. Because of teh LOW
OXYGEN atmosphere, the compounds that self-assembled were stable. Can’t
happen now because of high oxygen
d. In beginning, some think panspermia was how life got to earth - that life came to
earth in space rocks. Asteroids in Antarctica, originally from mars, has fossilized
life on it.
3. Grow and Develop
a. All life has growth and development that is regulated by a genetic code
b. Ex, crystals can grow, but it’s regulated by physical conditions in environment.
We grow b/c our genetic code tells us to
4. Energy Utilization
a. All life can consume nutrients, and can convert energy to do work - some energy
lost as heat
5. Homeostasis
a. All life has the ability to regulate its internal environment within tolerable limits
b. Ex, when we get cold, we shiver to maintain homeostasis
, 2
c. Maladaptations - originally, goosebumps brought out the down fur. But now,
we’re not furry, and goosebumps happen when we get cold, but they then increase
our SA, making us colder
6. Evolutionary Adaptations
a. Over time, populations/species will develop adaptations that help them to be
better suited for the environment around them
b. Ex, galapagos iguanas eat algae in water, and they got black skin to help
camouflage and to absorb heat in the cold waters, and they can hold their breath
forever
7. Carbon-based Chemistry (on Earth)
a. All life on Earth is made of carbon based molecules
b. Carbon undergoes 4 chemical bonds - so they form in chains, and still have two
more bonds for non-carbon atoms
c. Silicon does the same - but, oxygen reacts with it, and causes bigger chains to
break up, so on earth, silicon based life can’t be. On another planet, perhaps
d. Carbon breaks into CO2 eventually, but it happens super slowly
e. Other elements don’t work because their atoms are too big, and can’t form in big
chains
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Scientific Method, described
● Biology uses a rigorous set of ruled to investigate phenomena - called the Scientific
Method
● It’s universal, has rigid rules, and is ONLY for natural phenomena, uses only natural laws
● Can’t prove God - God by def. Is supernatural
Scientific Method in Steps
, 3
1. An observation of some phenomena
2. Hypothesis is developed to explain this phenomena
a. A hypothesis is NOT an educated guess - it is a tentative (subject to change)
conjecture (explanation) based on the existing evidence
b. To be a scientific hypothesis, it must be TESTABLE
i. Ex, Intelligent Design is NOT science, because because you can’t test it
ii. String Theory (multiple universes/dimensions) NOT science, bc not
testable
c. Hypotheses and experiments MUST be repeatable - credibility only comes when
repeated and peer reviewed rigorously
i. Ex, in the 90s, some dudes did an experiment and thought they’d proved
cold fusion - but, others repeated the experiment, and it turns out they’d
made a little error
3. Predictions are made from hypotheses, about what should occur if that hypothesis is true
4. Design Experiments/gather observations to gather testable evidence about the
hypothesis - so you get evidence to test the hypothesis
5. Statistically analyze your data, come to one of two outcomes: hypothesis supported or
not supported
a. If data does support it, you CANNOT claim that you’ve proven your hypothesis -
simply, you haven’t proved it wrong. It’s simply not rejected.
6. Publish your results so others can recreate the experiment - it needs repeatability
a. Publishing bias - publications are biased towards positive results. It’s harder to
publish something that proved a hypothesis false, even though false experiments
are just as important as “true” experiments
Creating an Experiment
Biology Lecture Notes
Characteristics of Life
1. Complexity
a. Life is complex compared to the background environment
2. Reproduction
a. Life abides by the rule biogenesis - life gives birth to like, life comes from life
b. Before, they thought abiogenesis (life just happening) was a thing. But, Pasteur
proved this wrong by not letting stuff come in and lay eggs on rotten meat
c. BUT - in the beginning, some think life sprung about. Because of teh LOW
OXYGEN atmosphere, the compounds that self-assembled were stable. Can’t
happen now because of high oxygen
d. In beginning, some think panspermia was how life got to earth - that life came to
earth in space rocks. Asteroids in Antarctica, originally from mars, has fossilized
life on it.
3. Grow and Develop
a. All life has growth and development that is regulated by a genetic code
b. Ex, crystals can grow, but it’s regulated by physical conditions in environment.
We grow b/c our genetic code tells us to
4. Energy Utilization
a. All life can consume nutrients, and can convert energy to do work - some energy
lost as heat
5. Homeostasis
a. All life has the ability to regulate its internal environment within tolerable limits
b. Ex, when we get cold, we shiver to maintain homeostasis
, 2
c. Maladaptations - originally, goosebumps brought out the down fur. But now,
we’re not furry, and goosebumps happen when we get cold, but they then increase
our SA, making us colder
6. Evolutionary Adaptations
a. Over time, populations/species will develop adaptations that help them to be
better suited for the environment around them
b. Ex, galapagos iguanas eat algae in water, and they got black skin to help
camouflage and to absorb heat in the cold waters, and they can hold their breath
forever
7. Carbon-based Chemistry (on Earth)
a. All life on Earth is made of carbon based molecules
b. Carbon undergoes 4 chemical bonds - so they form in chains, and still have two
more bonds for non-carbon atoms
c. Silicon does the same - but, oxygen reacts with it, and causes bigger chains to
break up, so on earth, silicon based life can’t be. On another planet, perhaps
d. Carbon breaks into CO2 eventually, but it happens super slowly
e. Other elements don’t work because their atoms are too big, and can’t form in big
chains
---------------------------------------------------------------------------------------------------------------------
Scientific Method, described
● Biology uses a rigorous set of ruled to investigate phenomena - called the Scientific
Method
● It’s universal, has rigid rules, and is ONLY for natural phenomena, uses only natural laws
● Can’t prove God - God by def. Is supernatural
Scientific Method in Steps
, 3
1. An observation of some phenomena
2. Hypothesis is developed to explain this phenomena
a. A hypothesis is NOT an educated guess - it is a tentative (subject to change)
conjecture (explanation) based on the existing evidence
b. To be a scientific hypothesis, it must be TESTABLE
i. Ex, Intelligent Design is NOT science, because because you can’t test it
ii. String Theory (multiple universes/dimensions) NOT science, bc not
testable
c. Hypotheses and experiments MUST be repeatable - credibility only comes when
repeated and peer reviewed rigorously
i. Ex, in the 90s, some dudes did an experiment and thought they’d proved
cold fusion - but, others repeated the experiment, and it turns out they’d
made a little error
3. Predictions are made from hypotheses, about what should occur if that hypothesis is true
4. Design Experiments/gather observations to gather testable evidence about the
hypothesis - so you get evidence to test the hypothesis
5. Statistically analyze your data, come to one of two outcomes: hypothesis supported or
not supported
a. If data does support it, you CANNOT claim that you’ve proven your hypothesis -
simply, you haven’t proved it wrong. It’s simply not rejected.
6. Publish your results so others can recreate the experiment - it needs repeatability
a. Publishing bias - publications are biased towards positive results. It’s harder to
publish something that proved a hypothesis false, even though false experiments
are just as important as “true” experiments
Creating an Experiment
