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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