Transcript AC Biology 1.1 ppt

Chapter 1
The Science of Life
The Study of Life
• Biology: the study of living things
• Some Fields of Biology: entomology (insects)
parasitology (parasites)
microbiology (bacteria)
ornithology (birds)
herpetology (reptiles)
Six Major Themes of Biology
• Cell structure and function
• Stability and homeostasis
• Reproduction and inheritance
• Evolution
• Interdependence of organisms
• Matter, energy, and organization
Cell Structure and Function
• Cells are the basic
unit of life
• All organisms are
made of and develop
from cells
Unicellular Organisms
• Organisms composed
of only one cell
• Examples: bacteria
and protists
Multicellular organisms
• Organisms composed
of more than one cell
• May be highly
complex
• Examples: plants and
animals
Facts about cells:
• Cells are highly organized
• Contain specialized structures
• There are many different kinds of cells
• Contain genetic material
Differentiation
• In multicellular organisms, cells become
different as they grow and develop
• After fertilization, cells divide and will
eventually become specialized
Stability and Homeostasis
• Living things maintain
stable internal
conditions
• Examples: body
temperature, water
content, electrolytes
Reproduction and Inheritance
• Organisms transmit hereditary information
to their offspring
• DNA (deoxyribonucleic acid)
• Gene: a short segment of DNA that
contains instructions for a single trait
Sexual Reproduction
• Production of
offspring from the
combination of
genetic material from
two parent organisms
• Example:
sperm + egg = zygote
Asexual Reproduction
• Doesn’t require two
different organisms
• One cell gives rise to
two cells
• Example: binary
fission in bacteria and
protists
Evolution
• Evolution= a genetic change in a
population over a long period of time
• Natural selection: organisms that have
favorable traits will survive better and pass
those traits on to their offspring
Evolution by Natural Selection
• Driven by competition
among individuals for
resources
• Individuals that can
survive will be able to
mate
• Traits are inherited by
offspring
Interdependence of Organisms
• Ecology: the study of
the interactions of
organisms and their
environment
• Ecosystems=
environmental
communities
Fragile Environments
• All life is
interconnected
• When one aspect of
the environment is
harmed, it will have a
negative impact on
the whole ecosystem
Matter, Energy, and Organization
• Almost all energy on Earth comes from the
sun
• Photosynthesis- plants capture energy
from the sun use it to manufacture
glucose
Autotrophs
• Organisms that make
their own food
• “self-feeders”
• Example: plants
Heterotrophs
• Organisms that must
take in food to meet
their energy needs
• “other-feeders”
• Examples: rabbits,
coyotes, bears
Conclusion
• Biology is the study
of life, ranging
from the study of
unicellular
organisms to the
study of global
interactions among
millions of
organisms
All forms of life deserve protection
and respect