CHAPTER 1
Introduction: Themes in the Study of Life
Overview: Inquiring About the World of Life
Biology is the scientific study of life.
Biology is an ongoing inquiry about the nature of life.
Life is recognized by what living things do
Cells are an organism’s basic units: The cell is the lowest level of organization that
can perform all activities required for life.
Order: Life’s basic characteristic is a high degree of order.
Energy processing: Living things acquire materials and energy.
Reproduction: Organisms reproduce their own kind. Life comes only from life.
Growth and development: Living things grow and develop.
Response to the environment: Living things respond to stimuli.
Regulation: Regulatory mechanisms maintain an organism’s internal environment
within tolerable limits, even though the external environment may fluctuate. This
regulation is called homeostasis.
Evolutionary adaptation: Living things are adapted. Life evolves as a result of the
interaction between organisms and their environments. One consequence of evolution is
the adaptation of organisms to their environment.
Concept 1.1: Themes connect the concepts of biology
Biology is a subject of enormous scope
Themes help to organize biological information
Theme : Evolution, the Overarching Theme of Biology
Evolution makes sense of everything we know about living organisms.
The scientific explanation for the unity and diversity, and for the suitability of organisms
to their environments is evolution.
Theme : New properties emerge at each level in the biological hierarchy
The study of life can be divided into different levels of biological organization
Life can be studied at different levels from molecules to the entire living planet
The biosphere:
o Consists of all the environments on Earth that are inhabited by life.
o Includes most regions of land, most bodies of water, and the atmosphere to an
altitude of several kilometers.
Ecosystem:
o Consists of all the living things in a particular area, along with all the nonliving
components of the environment with which life interacts, such as soil, water,
atmospheric gases, and light.
o All the Earth’s ecosystems combined make up the biosphere.
Communities:
o The entire array of organisms which inhabit a particular ecosystem.
o Each of these forms of life is called a species.
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Populations:
o Consists of all the individuals of a species living within the bounds of a specified
area.
o The set of populations that inhabiting a particular area make up community.
Organisms:
o Are individual living things.
Organs and Organ Systems:
o An organ carries out a particular function in the body.
o A team of organs that cooperate in a specific function is called an organ system.
Tissues:
o A group of similar cells.
Cells:
o Is life’s fundamental unit of structure and function.
Organelles:
o The various functional components that make up cells.
Molecules:
o A molecule is a chemical structure consisting of atoms.
Emergent properties
result from the arrangement and interaction of parts within a system
Emergent properties characterize nonbiological entities as well
o For example, a functioning bicycle emerges only when all of the necessary parts
connect in the correct way
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