Sem 1 : Cycle 1 : GenBio
Biology Review
The Unity and Diversity of Life
Living things are organized into levels of biological organization
● The living organizing on our planet shows tremendous diversity in form and distribution.
● Despite diversity, all organisms share certain characteristics that distinguish them from
nonliving things.
● The similarity in these characteristics provides that all organisms descended, or evolved
from a common ancestor.
● The cell is the most basic unit of life.
● Similar cells together form tissues.
● Similar tissues together form organs.
● Organs work together in the organ system.
● Organs systems form complex organisms.
● Complex organism together form higher levels of organizations
Levels of Biological Organization
Living things acquire materials and energy.
● The chemical reactions that occur in cells are a part of metabolism. Some reactions
extract nutrients, building materials and energy from food.
○ Photosynthesis involves chemical reactions that use solar energy to form
chemical energy.
● For metabolism to continue in cells, all chemical reactions must be kept in a balance
called homeostasis.
Living things respond, reproduce, and develop.
● Organisms interact with, and respond to, their environment, often with movement.
● Every type of living organism can reproduce (produce another organism like itself).
○ Unicellular organisms reproduce by cell division.
○ Multicellular organisms use sexual reproduction.
Notes by: Dominique Gloria 12B
Living things have adaptations
● Adaptations are modifications that make a particular type of organism (i.e., a species)
suited to its way of life.
● Species become modified over time by natural selection, which preserves genetic
changes that make them better suited for their environment.
● Evolution is descent with modification, driven by the process of natural selection.
How the Biosphere is Organized
The biosphere includes the land, sea, and air and all organisms on Earth.
● Individuals of the same species belong to a population.
● The populations of species in a given area are the community.
● The interaction of communities with the environment forms an ecosystem.
How Organisms are Classified
● Because living things are diverse, taxonomy was created to group organisms into
categories and to understand their evolutionary relationships.
○ Domain
○ Kingdom
○ Phylum
○ Class
○ Order
○ Family Genus
○ Species
Notes by: Dominique Gloria 12B
There are three domains of living organisms
● The Domain Archaea and Bacteria are both composed of prokaryotic bacteria.
○ Archaea bacteria live in extreme environments.
■ Anoxic (no oxygen)
■ High salinity
■ High temperature
● The Domain Archaea and Bacteria are both composed of prokaryotic bacteria.
○ Domain Eukarya consists of all non- bacterial organisms. Eukarya is divided into
four kingdoms.
■ Protista
■ Fungi
■ Plantae
■ Animalia
Four Kingdoms of Eukarya
Notes by: Dominique Gloria 12B
Organisms within kingdoms are given scientific names
● Unique scientific names are used to identify and classify organisms.
● The scientific name is called the binomial name and consists of a genus and species.
○ Peas: Genus = Pisum; species = sativa
○ Humans: Genus = Homo; species = sapiens
The naming of living organisms has revealed the biodiversity of the Earth
● Biodiversity is the sum total of all organisms and their genetic information.
○ 15 million organisms are believed to exist on the Earth.
○ 400 species per day are lost to extinction.
● Conservation biology includes efforts to protect biodiversity and ecosystems.
Biology: The Study of Life
● Biology is the scientific study of life.
● Biology, like other sciences, studies life using the scientific method.
○ Make an observation
○ Form a hypothesis via inductive reasoning
○ Conduct an experiment, collect data, make further observations
○ Reach a conclusion
○ Formulate a theory
Scientific Method
Experiments performed in science have specific elements
● The experimental design is the well-conceived plan for a specific experiment.
Notes by: Dominique Gloria 12B
● Experiments typically have two groups.
○ Experimental group - the group manipulated during the experiment.
○ Control group - the reference group, left unmanipulated
● Experiments collect data.
An Example of a Controlled Study
● Hypothesis: Pea plants grown in soil before winter and turned into the soil would provide
a natural fertilizer for winter wheat.
● Control group: Winter wheat planted with no treatment.
● Experimental groups: Wheat plants in soil with fertilizer (45 kg ha -1 ).
○ Wheat plants in soil with double fertilizer (90 kg ha -1 ).
○ Wheat plants in soil containing pea plants that were turned into the soil.
● Conditions: All groups watered and exposed to the same conditions.
● Data collected: Weight of wheat plants in the spring.
● Conclusion: Hypothesis not supported.
Science and Society
● The application of science for a practical purpose is called technology.
● Science is impartial and does not make ethical or moral judgments.
● The role of society is to use scientific information to make informed decisions about the
use of technology.
Characteristics of Life
● Bio - Living ; Logy - Study
● Study of living things; anything which interacts with its environment uses energy and
reproduces are known as living things.
Notes by: Dominique Gloria 12B
7 Characteristic of Life
Order Highly ordered structure that typifies life.
Living cells are the basis of this complex
organization.
Reproduction Organisms reproduce their own kind.
Growth and Development Inherited information in the form of DNA,
controls the pattern of growth and
development of all organisms.
Energy Processing Humans eat food to get energy and the food
we eat has also eaten some food to utilize its
chemical energy stored in order to power its
own activities and chemical reaction.
Response to the Environment All organisms respond to environmental
stimuli. (laughing when tickled)
Regulation Many types of mechanisms regulate
organisms' external environment keeping
them within limits that sustain life. Also
called homeostasis.
Evolutionary Adaptation Lion camouflage to blend in with the
savannah so they can easily hunt for food.
Notes by: Dominique Gloria 12B
