Download BIO 101 Chapter 1 Lecture Notes * WHAT IS LIFE?

BIO 101 Chapter 1 Lecture Notes – WHAT IS LIFE?
I.
The 7 characteristics of Life
1. Order – Living things are made up of one or more cells. The cell is the fundamental unit of
life.
2. Reproduction – All living thing have the ability to make their own kind. This allows for
propagation of the species.
3. Growth and Development – Different parts of the organism’s DNA will the activated at
different times points during development causing an increase in size and increase in
number of cells (for multicellular organisms).
4. Energy Processing – All living things acquire energy process thing energy in order to
convert it into a form that can be used by the organism.
a. Photosynthesis
b. Metabolism
5. Responds to the Environment – Living things respond to external stimuli (stimuli in the
environment).
a. Leaves will orient themselves so that they get the maximum amount of sunlight.
b. Leaves will close their stomata (similar to pores in our skin) when it is too hot and
they want to conserve water.
c. Animal use their senses to gather information from the environment about
impending danger or food sources, etc.
6. Regulation (Homeostasis) – Living things respond to changes in the internal and external
environment in such a way to maintain its physiological factors and keep them within a
narrow range. Failure in homeostasis results in illness or death.
a. Shivering when cold raises core body temperature.
b. Goose bumps are caused from pilomotors in your skin that cause your hair to stand
up in response to cold or strong emotion.
i. This is an evolutionary artifact from when we had more body hair.
ii. Makes animal look bigger - gives a warning
iii. May have helped with warmth
c. When a person or animal gets too cold, the circulatory system responds by
restricting blood flow to the colder extremities of the body (hands, feet, nose, etc) in
order to keep the blood from losing to much heat. This protects the internal organs
from getting too cold. This is what happens in frostbite.
d. When a person is very active (or exercising) the body diverts the blood away from
the core of your body which houses your internal organs (such as the digestive
tract) and directs that blood flow to your limbs and muscles.
i. Active muscles have higher demand for blood flow.
ii. Eating just before rigorous exercise can cause nausea.
7. Evolutionary Adaptation - is the process a living thing goes through in order to become
accustomed to an environment.
a. occurs over many generations
b. The result of successful adaptation is always beneficial to an organism, thus relating
it to the process of natural selection.
i. An anteater has a long snout to get at the ants.
II.
The Hierarchical Levels of Organization of life (see page 3 in text) - new properties
emerge at each level of increasing complexity.
1. Atom – considered the fundamental unit of all matter
a. All life as we know it is Carbon-based
b. The Carbon atom has the ability to create up to 4 strong bonds, allowing for the
complexity needed for life.
c. The human body is 97 % Carbon, Hydrogen, Oxygen and Nitrogen
d. Atoms are 99.999999999999999% empty space
2. Molecule – two or more atoms come together to form a molecule
i. The four basic categories of molecules for building life are
1. Carbohydrates - sugars
2. Lipids - fats
3. Proteins – amino acids
4. Nucleic acids – building block of DNA
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ii. Nucleic acids, DNA
3. Organelle – molecules come together in living organisms to form organelles which are like
tiny organ of the cell.
a. Organelles function in cells similarly to how our organs function to perform specific
tasks in our bodies.
4. Cell - Organelles come together to form a cell which is the fundamental unit of life.
5. Tissue – Cells of the same type come together to form tissues (of that same type)
a. Examples:
i. Neurons come together to form nervous tissue
ii. Epithelial cells come together to form epithelial tissue (skin)
iii. Muscle cells come together to form muscle tissue
6. Organ – tissues come together to form organs
a. part of an organism that is typically self-contained and has a specific vital function
i. lungs
ii. heart
iii. liver
iv. brain
7. Organ System – two or more organs come together to carry out a specific function in the
body
a. Examples
i. Cardiovascular System
ii. Nervous System
iii. Digestive System
8. Organism – organ systems come together to create a living individual
9. Population – Organisms of the same species will form a population of that species
10. Community – Populations of different species will coexist in a given area to form
communities
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11. Ecosystems – Now we add in the non-living (abiotic) components and living (biotic)
components of a given area.
12. Biosphere – Our planet
III.
Cells
1. Fundamental unit of life
2. All living things are made up of one or more cells
3. Cell types
a. Prokaryotic
i. More primitive – simpler - smaller
ii. Does not have compartmentalization – no membrane-bound organelles and
no nucleus
b. Eukaryotic
i. Includes:
1. Plants
2. Animals
3. Fungi
4. Protists
ii. Has nucleus
iii. Has membrane-bound organelles
iv. Evolved later
v. More complex - larger
c. Archaea
i. Used to be considered bacteria, but now seen as a distinctly different cell
having features in common with both prokaryotic and eukaryotic cells.
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