CHAPTER 1: A VIEW OF LIFE
CHAPTER 1: A VIEW OF LIFE
B. An ability to acquire materials and energy
1. Energy: the capacity to do work metabolism: all the chemical
reactions that occur in a cell
2. Photosynthesis: capture solar energy
3. Homeostasis: maintain a stable internal environment, by behavior,
metabolism, hormones, nervous system
C. Respond to their environment
1. Often results in movement toward safety
2. Appropriate responses help ensure survival
D. Reproduce and Develop
1. Life comes only from life
2. Blueprint inherited from parents encoded in genes
3. Genes are made of DNA, give specific information for that organism
4. Multicellular organisms typically increase in size
E. Adaptations: modifications that enable an organism to survive
1. Natural selection: process by which populations can become
modified over time
2. Species: unit of evolution: defines a a group of interbreeding
individuals
II. Theory of evolution: descent with modification
A. Decent from common ancestor explains unity of life: commonalities
1. Cells
2. Elements: C, H, O, N, P, S
3. Water based
4. All need energy
a. Autotroph: self-feeding, plants, algae, microbes
b. Heterotroph: feeding on others, animals
B. Adaptation explains diversity. Produces differences among individuals and
species.
III. Ecosystems
A. Food chain: sequence of flow of energy through organisms (1)
B. Inorganic nutrients cycle through death and decay
C. Energy is a one-way flow of energy from the sun, "lost" as heat
D. Ex) tropical rain forest: most complex terrestrial ecosystem
F. Human population modifies existing ecosystems and reduce biodiversity
IV. Classification system: group organisms according to their similarities
A. Taxonomy: science of identifying and classifying organisms
1. Beginning ancient times scientists have tried to develop a system of classification for animals and plants.
1. Carl Linnaeus: (1707-1778) developed the modern system of
2. Suggested the use of a binomial name to identify organisms.
Genus species.
3. Suggested hierarchical system of classification
B. Levels of classification-Brown Squirrel
1. Kingdom-Anamalia (Most Inclusive)
2. Phylum for animals, Division for plants-Chordata
3. Class-Mammalia
4. Order-Rodentia
5. Family-Scuridae
6. Genus-Tamiasciurus
7. Species: similar characteristics and produce fertile offspring-
hudsonicus (Least inclusive)
C. Five Kingdom system
1. Monera: bacteria and cyanobacteria (blue green algae)
2. Protista: single celled organisms, sometime in colonies, or
multicelled
3. Fungi: mushrooms, and molds
4. Plantae: plants
5. Animalia: animals
V. Process of Science: objective, seek to understand the natural world by
observing and testing, subject to change
A. Scientific method
1. Accumulated scientific information
2. Hypothesis: a possible explanation
3. Hypothesis often developed by inductive reasoning-use of
isolated acts and creative reasoning
a. Explains past information
b. Allows prediction of future events
c. Is testable
d. Can be proved false, not true
1. Eg., hypothesis-aggression of male bluebirds
varies during the reproductive cycle
3. Observations/experiment: a way of testing the hypothesis
a. Deductive reasoning: logical reasoning using "if...then"
statements
1. if hypothesis true, then would expect
aggression to shift as the reproductive cycle
progresses.
b. Experimental variable: a factor that is different and the
focus of testing
1.. presence or absence of model male bluebird
c. Dependent variable: effects of the experiment
1. amount of male aggression
d. Control: goes through all the steps of the experiment
except the one being tested
1. presence of model male robin.
2. Insures that results due to experimental variable.
3. may be difficult to control certain experimental
variables
e. Data: often mathematical, graphs, diagrams, drawings
1. defined aggression as # of approaches per minute
2. plotted data on graph
f. Conclusions: what did you learn from doing the
experiment
B. Scientific theory: concepts that join together well supported and
related hypotheses. Eg.,
1. cell theory-all organisms composed of cells
2. biogenesis-life comes only from life
3. evolution-descent with modification
C. Law or principle: theory that is generally accepted as valid, ex.
gravity, evolution