1. Biology: Science of Life
What do Biologists do?
Study past, present and future life
Interactions, structures, functions
Solve biological problems
Agriculture
Disease
Conservation/Remediation to maintain diversity of life

2. What is life? We decide Has or once had the following characteristics:
1+ cells
Organized/Complex
Grows and develops
Maintain Homeostasis
Reproduces
Responds to Stimuli
Uses Energy
Adaptations Evolve
Humans have constructed this definition of life?
What about viruses?
What about evolution?

3. The cell is the basic unit of life Organized/Complex
1+ cells
The cell is the basic unit of life
unicellular v. multicellular v. acellular
Organized/Complex
Chemical complexity for structure and function
Structural organization: Atoms molecules cells tissues organs organ systems organism (assuming multicellular)
How do we amend this sequence if the organism is unicellular?
Consider an example or analogy to describe the meaning of “basic unit”
Growth and development are different

4. Growth: addition of mass
Homeostasis
Regulate internal conditions
ex: temp, water, blood sugar
Grow/develop
Growth: addition of mass
Increase cell size and/or increase cell number
How does a unicellular grow; a multicellular?
Development: change over time
Go through stages of maturity
Consider an example or analogy to describe the meaning of “basic unit”
Growth and development are different

5. Respond to Stimuli Stimulus response Use Energy
Able to process and react to internal/external environ.
Stimulus response
Use Energy
Get/make food (chemical energy) to fuel metabolism, convert energy (ATP) to power processes, maintain chemical disequilibrium
Categorizations for how “food” is obtained by life:
Autotroph (chemoautotroph or photoautotroph)
Heterotroph (by ingestion or by absorption)
Species concept is under scrutiny because it does not always play out – what about hybrids?
What is external stimuli?
What is internal stimuli – think about blood sugar, temp, water balance…
We will talk about ATP a lot…it is the energy currency of the cell
Adaptation does not happen to individuals and time refers to generations

6. More on Autotrophy… There are two general processes:
___________________
use sun as energy needed to make food
____________________
use chemicals as energy to
drive “food making” process
Hydrothermal deep sea vents

7. Adaptations/Evolution
Reproduce
Species = group of organisms that can interbreed to produce viable (fertile) offspring
What about individuals that cannot bear offspring??
Adaptations/Evolution
Change in inherited traits (genetics) in a population/species over time (generations) due to reproduction
Genetic variation is a generally good thing for species survival
Individuals do not biologically evolve!
Species concept is under scrutiny because it does not always play out – what about hybrids?
What is external stimuli?
What is internal stimuli – think about blood sugar, temp, water balance…
We will talk about ATP a lot…it is the energy currency of the cell
Adaptation does not happen to individuals and time refers to generations

8. Details on Characteristics
Cells:
Unicellular
Multicellular
1st life forms
Evolved later
1 cell
More than one cell
All bacteria, most protists, some fungi
All animals, all plants, some fungi
GROW by cell enlargement only
GROW by cell enlargement and cell division
REPRODUCE by cell division (asexual reproduction/cloning)
REPRODUCE mainly by making specialized cells that combine sexually

9. Details on Characteristics II
REPRODUCTION:
Asexual
Sexual
Evolved first
Evolved later
Unicellular organisms divide to make more identical unicellulars
Multicellular organisms use meiosis to make sperm/egg
One “parent” – contributes 100% of genetic info
Two “parents” – each contribute 50% of genetic info
Make a clone – no genetic variation between generations
Genetically different offspring – more variation in population – GOOD for survivability/evolution

10. Details on Characteristics III
Energy use
Autotrophs
Heterotrophs
BOTH versions of organisms convert “food” energy into ATP energy to power their cellular processes!!
All plants, some bacteria, some protists
All animals, All fungi, some bacteria, some protists (NOTE: some plants can do this too! “carnivorous plants –VFT!)
AKA “producers”
AKA “consumers”
Make own food
Eat other organisms or the products of other organisms
Two versions:
Photosynthesis
Chemosynthesis

11. Details on Characteristics IV
Adaptation/Response
Adaptation (evolution)
Response (to stimuli)
Long-term
Short-term
Population response to changing environmental conditions
Immediate feedback to stimuli
More genetic variability in the population = the better able the population can adapt
EX: adaption as a result of changing climate – thicker fur
EX: response to changing temperatures – burrow, put on a coat

12. Life vs. Viruses Viruses: are acellular
Bacteria (2 kingdoms), protists, fungi, plants and animals are living; viruses are NOT
living things exhibit ALL characteristics of life
NOTE: if you need a microscope to see, it is called a “microbe” or “microorganism”; if it causes disease we called a “pathogen”.
MOST bacteria do not cause human illness!
Viruses:
are acellular
do not (generally) reproduce themselves
do not use energy/ have a metabolism

13. Chapter 1.1 Big Concepts
Understand that there are 6 kingdoms (big categories!) of life and viruses are not included in any of them
Reproduction of life can be sexual or asexual
Obtain energy via heterotrophy and/or autotrophy (chemoautotroph, photoautotroph)
Evolution results in adaptations in a population
Viruses are acellular; Life consists of prokaryotic or eukaryotic cells and is unicellular or multicellular
Living things can regulate their internal conditions (homeostasis)