AP Biology CMR @ CHS ‘95 B.Rifepage 1 /5
I. Unit 1:
The Life of Cell - Chapter 1
1.1 Biological Diversity Can Be Arranged Into Five Kingdoms
I Characteristics of Life
A. Living Things are Organized
Living things are composed only of chemicals (atoms & compounds) and obey the same chemical and physical laws as nonliving things.
The cell is the smallest most basic unit of life.
chemicals --> cells --> tissues --> organs --> organ systems ---> organisms
Taxonomy is the science of classification, which provides a logical international system for the naming of organisms.
Our system of classification, known as the binomial system (two names), was originated by a Swedish biologist named Linnaeus.
Each organism is given a scientific name consisting of two Latin words.
The first word of the scientific name, always written with a Capital, is the generic name, that is, the name of the genus in which the organism is placed.
The second word is the specific name, which is not capitalized, and is the species of the organism.
Thus the mallard duck, which occurs almost throughout the world, may be known by many common names in various countries, but its scientific name, Anas platyrhynchos, is the same everywhere.
Each species belongs to a series of higher categories, also originated by Linnaeus. This hierarchical classification includes, from greatest to smallest, the following categories:
EXAMPLES:
HUMANASPEN
KINGDOM(king)ANIMALIAPLANTAE
PHYLUM(Philip)CHORDATA TRACHEOPHYTA
CLASS(came)MAMMALIA ANGIOSPERMAE
ORDER(over)PRIMATES APETALAE
FAMILY(for)HOMINIDAESALICACEAE
GENUS(good)Homo Populus
SPECIES(soup)sapiens tremuloides
There are five recognized kingdoms in the classification system. They are:
Monera - The moneran kingdom includes all bacteria and the blue green algae. Monerans are unicellular prokaryotes.
Protista - The protist kingdom includes the protozoans (first life). Many protists are unicellular microscopic organisms. Protists are eukaryotes.
Fungi - Most fungi are multicellular organisms that have simple structures. All fungi are eukaryotes, and heterotrophic.. This kingdom includes mushrooms, molds, and yeast.
Plantae - Most are multicellular organisms with specialized tissues and organs. Plants are autotrophic, that is they make their own food from simple substances, and contain chlorophyll. Plant cells have cell walls.
Animalia - The animal kingdom is made up of only multicellular organisms. Animals are heterotrophs. These organisms are the most complex, have tissues, and most have organs and organ systems. Animal cells do not have cell walls or chlorophyll.
1.2 Common Threads Connect All Of Life
Living Things Metabolize
Metabolism - is all the chemical ad energy transformations that occur in cells to maintain the cell’s organization.
Homeostasis - the maintenance of internal conditions within certain boundaries. Conditions such as temperature, pH, blood pressure, water, salt, & sugar concentrations are under homeostasis.
Living Things Respond
Irritability - is the ability to respond to a stimulus.
Taxes - are the locomotor responses by which an organism orients itself toward or away from particular stimuli.
Thermotaxis - response to heat
Phototaxis - response to light
Thigmotaxis - response to contact
Chemotaxis - response to chemical substances
Living Things Reproduce
Biogenesis - Life comes only from life
Heredity - The sum of genetic characteristics from the parents.
1.3 Evolution Is The Core Theme Of Biology
Living Things Evolve
Evolution - The process by which the characteristics of organisms change over time
-The processes of biological and organic change in organisms by which descendants come to differ from their
-ancestors.
Common characteristics found in all life indicate that there is a unity to life. Such remarkable uniformity can be explained by the descent of organisms from a common ancestor (Darwin’sevolution)
Adaptation - is any peculiarity of form or function or behavior that promotes the likehood of a species continued existence.
Specific adaptations to many ecosystems explain the diversity of life.
1.4 Science Is A Powerful Approach For Understanding Life
Science - is a study concerned with the observation a classification of facts concerning the physical world.
- is a process that produces a body of knowledge about nature.
Technology - is the application of science for a practical purpose,
the betterment of the human condition. (May be good or evil?)
A scientist is a person who uses a certain approach to learn about and explain natural features
Data - is factual information
Hypothesis - is an educated guess about a problem that is based on information obtained by observation
- is a tentative statement for investigation
Theory - A plausible or scientifically acceptable general principle to explain observed facts (which hasn’t been disproven)
- An explanation backed by results obtained from repeated tests or experiments.
Before a hypothesis can be elevated in rank to that of a theory, it must be tested many times during a long interval of time. The results of the tests must continue to support the hypothesis.
Law (Principle) - The observed regularity of nature. (The law of gravity)
Inductive Reasoning - uses isolated facts to arrive at a general idea that might explain a problem. (specific --> general)
Deductive Reasoning - begins with a general statement that infers a specific conclusion. (general --> specific) If - then statements
Certainty in Science
Science is not an end in itself but only a tool to explore and learn more about our surroundings.
Science is always in a perpetual state of change. Quite often in science, new studies, which might utilize new techniques and equipment, indicate that previous conclusions need to be modified or changed entirely.
The laws and theories are “Truth” not in the absolute but only relative to our understanding and current time on Earth.
Some of “our” theories will no doubt as amusing to those in the future as the theory of a geocentric (Earth centered) solar system is to us.
1.5 Biologists Use The Scientific Method
Scientific Method - is a problem solving approach
- is the best most logical way to explain natural events.
Steps of the Scientific Method:
1. Identify the problem and state it carefully
2. Collect as much information as possible about the problem (observation)
3. State Hypothesis
4. Test the Hypothesis (Experimentation and/or observation)
5. Draw conclusions about the hypothesis (Accept or reject hypothesis)
6. Report the conclusions so other scientists can test the hypothesis
Reporting the Experiment
It is customary to report findings in a scientific journal (lab writeup) so that the design of the experiment and the results are available to all.
Controlled Experiments
1. Elements of an Experiment All conditions should be held constant except the one being tested.
Experimental variable - the variable being tested
Dependent Variables - the effects, results, or outcome of the experiment due to changes in the experimental
variable.
Control Group - experiences on variables of the experiment except the one being tested (Experimental variable)
2. Design of an Experiment
Experiments should be designed with one or more control groups and a number of experimental groups with the
experimental variable quantitatively varied
3. Results of an Experiment
A statistical test should be run to determine if the differences between the experimental groups and control groups
are statistically significant (Chi-square test)
Descriptive Research
Much data scientist gather is purely observational, but the scientific method is still applicable.
Research based mainly on observation can develop scientific models that suggest explanations to direct further research.
1.6 Life Is Organized At Different Levels
The levels at which life is organized are (from smallest to largest)
chemicals --> cells --> tissues --> organs --> organ systems ---> organisms --> populations --> communities -->
----->ecosystems
Population- a group of organisms of the same species that occupy a specific environment.
The Human Population - The human population tends to modifying existing ecosystems for its own purposes. More and more ecosystems undergo modification as the human population increases.
Community- Many different populations of organisms that interact with each other.
Ecosystem - includes all of the plants and animals of the area, as well as the soil, air, and water of the area or
- A community of plants and animals together with the physical factors of their environment.
Biosphere - is the life zone of the earth, including the lower part of the atmosphere, the hydrosphere, and the lithosphere.
1.7 At All Levels In Life’s Hierarchy, The Whole Is Greater Than The Sum Of Its Parts
Special features that result from a system’s particular organization, and that don not exist without this organization, are called emergent properties.
The appearance of emergent properties from underlying organization is one of the most important characteristics of life.
The emergent properties of one level come from the precise manner in which the parts of the next smaller level are organized.
1.8 A Precise Structural Order And A Resulting Set Of Emergent Properties Define Life
A precise structural order and a resulting set of emergent properties define life (What is life?)
1. A precise structural organization at each level.
2. The ability to take in energy and use it (metabolism)
3. The ability to respond to stimuli
4. The capacity for growth and development
5. The ability to reproduce
6. The ability to evolve
1.9 Life’s Properties Have A Chemical Basis
Organisms are composed of living and nonliving chemical matter.
The basic structure and behavior of these chemicals do not differ whether in living or nonliving things.
This chemical basis is discussed in detail in chapter 2.
1.10 The Continuity Of Life Depends On DNA
DNA is the basic chemical in the genes that pass from generation to generation
DNA encodes the blueprint for the growth, development, and function of every organism
The code is the same for virtually all organisms
The structure and function of DNA are covered in detail in Chapters 3 and 10.
1.11 All Organisms Are Composed Of Cells
Cells are the lowest level of organization that exhibits the complete set of the characteristics of life.
Organisms may be single-celled (cells are multifunctional) or multicellular (each cell type is restricted in its functions)
The relationship between form and function is particularly evident at the cellular level.
Cells are covered in depth in Chapter 4 and 5.
1.12 Every Organism Exhibits Clear Connections Between Form And Function
The close relationship between from and function is one of the core themes of biology.
This theme is characteristic of all structural levels in life’s hierarchy. (give examples)
1.13 Living Organisms And Their Environments Form Interconnected Webs
Living things do not exist in isolation from their environment. An organism’s environment includes other organisms.
There are many ways organisms from connections with other organisms.
energy flow, matter recycling, symbiotic.
Such webs are characteristic of the community and ecosystem levels
An emergent property of the organization at these levels is the cycling of nutrients among all components.
1.14 Biology Is Connected To Our Lives In Many Ways