Download Unit 1- The Science of Biology

Part 2- The World of Biology
 Definition of biology:
branch of science that studies life
Examples of some things a
biologist might study:
1.
2.
3.
4.
5.
How living things work, interact with environment,
change over time
Microbiology- tiny things such as viruses and
bacteria
Zoology- animals
Botany- plants
Human biology
Ways biology impacts our daily
lives
 Health- nutrition, disease, taking care of ourselves
 Animals, plants, other organisms in our environment
 Bacteria- they’re everywhere!!
 Awww…our pets!
Ways biology impacts human
society
 Environmental concerns
 Medical improvements
 Gene Technology-
genetic engineering,
DNA testing,
reproductive
technologies
 Food/water supplies for
our ever-increasing
world population
Living things share several characteristics, which
include the following
1.
2.
3.
4.
5.
6.
7.
8.
Organization and cells
Genetic code
Respond to stimuli
Maintain homeostasis
Metabolism
Growth and development
Reproduction
As a population, change over time
 Organization is the high degree of order within an
organism and with its interactions with its
environment. All living organisms, whether made up
of one cell or many cells, have some degree of
organization.
 Definition of cell: collection of living matter enclosed
by a barrier- smallest unit of an organism that can be
considered alive
 Unicellular organisms: organisms made of only one
cell (ex.- bacteria)
 Multicellular organisms: organisms made of many
cells (ex.- plant, cow, human)
Flow chart of organization in complex
multicellular organisms
 All organisms have a genetic code.
 You’ve probably noticed that offspring resemble their
parents in certain ways. Explaining how organisms
inherit traits is one of the greatest achievements of
modern biology!
 We now know that the directions for inheritance are
carried by a molecule called DNA.
 With minor exceptions, the DNA genetic code
determines the inherited traits of every organism on
Earth! It’s an amazing little molecule!!
 All organisms have the
ability to respond to
various stimuli (singular
form: stimulus) in their
environment.
 Definition of stimulus:
physical or chemical
change in an organism’s
internal or external
environment
 Examples of stimuli and responses by organisms:
 Owl dilates pupils as light goes down
 Person eats when she feels hungry
 Dog barks when doorbell rings
 Plant stem and leaves grow towards light
 Definition of homeostasis: The process by which
organisms keep their internal conditions relatively
stable
 Examples of ways that organisms maintain
homeostasis:
 Plant taking in and giving off water
 Bird maintaining constant body temperature
The condition of homeostasis is constantly being
threatened by changes in the environment such as
shifting temperatures and changing light. If
homeostasis is disrupted in a major way, what will
happen to an organism?
it will die
 Definition of metabolism: the combination of
chemical reactions through which an organism builds
up or breaks down materials as it carries out life
processes
 Examples of chemical reactions that are part of the
metabolisms of organisms:
 Photosynthesis of plants
 Breaking down of food by animals
 All living things grow, or increase in size. What causes
living things to grow?
 Changes an organism goes through during its life
cycle- involves cell division and cell specialization
(turning into different kinds of cells)
 Although individual organisms experience many
changes during their lifetimes, their basic genetic
characteristics do not change. However, populations
of living organisms evolve, or change over long periods
of time.
 The ability of populations of organisms to change over
time is important for survival in a changing world. It is
also an important factor in explaining the great
diversity of life-forms we see on Earth today.