Transcript Chapter 1 Lecture

Chapter 1
The Study of Life
• Earth is home to an incredible diversity of life.
– All living things and all the places they are found
on earth make up the BIOSPHERE.
• Every part of the biosphere is connected to every other
part of the biosphere, regardless of distance.
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Deserts
Grasslands
Wetlands
Savannahs
Forests
Tundra
The Study of Life
• The variety of life across the biosphere is
called BIODIVERSITY.
• Biodiversity is greater near the equator and
more sparse near the poles.
Biodiversity
• More species are able to survive in warmer
area than in colder areas.
• SPECIES can be defined as a group of living
things that are genetically similar enough to
interbreed and produce fertile offspring.
• There are about 2 million different species
identified thus far on Earth.
All Organisms Share Characteristics
• An ORGANISM is an individual living thing and
is made up of one or more CELLS.
• Cells are the basic units of life, are microscopic
and may have specialty functions.
– Muscle cells
– Sex cells
– Skin cells
– Brain cells (neurons)
All Organisms share Characteristics
• All organisms need energy to survive.
– Energy powers metabolic functions, or the chemical
processes required for life.
• All organisms must react to their environment.
– Sunlight, water, temperature, wind, food, etc. are all
external stimuli that organisms must adapt to in order
to survive.
• Reproduction and development.
– All organisms must be able to reproduce, either
sexually or asexually, and pass on DNA to their
offspring.
All Levels of Life Are Systematic
• A SYSTEM is an organized group of related
parts that interact to form a whole.
• In the living world, systems exist on all scales
from cells to organisms to entire ecosystems.
• An ECOSYSTEM is a physical environment with
different species that interact with one
another and with nonliving things.
Structure and Function
• Each part in a system serves a specific purpose
and therefore performs a specific function.
• This is true on all scales, just as with systems,
from the cellular level on up.
• Examples:
Organisms Maintain Homeostasis
• HOMEOSTASIS is the maintenance of constant
internal conditions in an organism.
– Uses negative feedback
– Examples:
Evolution
• EVOLUTION explains the unity and diversity of
life.
– The change is living things over time through
genetic modifications, called ADAPTATIONS.
Scientific Method Review
Variables
• Dependent Variable – observed and measured
during an experiment. These are not
manipulated, but affected by the independent
variable.
• Independent Variable – the variable that is
being manipulated. This is what you, as a
scientist change.
• Constants – The conditions that remain the
same during the experiment.
Data
• Quantitative Data – Deals with numbers, can
be easily measured
• Examples:
• Qualitative Data – Deals with descriptions.
Can be observed but not measured.
• Examples:
Biologists’ Tools and Technology
• Imaging technology provides new views of life.
– Microscopes provide enlarged images of objects
– In the classroom, we will be using light
microscopes often and will be able to see things
as small, or even smaller, than single cells
– Electron microscopes, found at some colleges, use
a beam of electrons to magnify objects
• Scanning Electron Microscopes (SEM) scans the surface
• Transmission Electron Microscopes (TEM) scans
through
Biologists’ Tools and Technology
• Medical Imaging
– Xrays, CAT scans, MRIs, fMRIs, Ultrasounds, etc.
Complex Systems are Modeled on
Computers
• Biologists have used computers and
developed new software to better model
living systems in order to make predictions
based on observations.
• Examples:
Molecular Genetics
• GENE – segment of DNA that stores genetic
information
• MOLECULAR GENETICS – study and
manipulation of DNA on the molecular level
(GMO food)
• GENOMICS – study and comparison of
genomes both within and across species
Biology and Your Future
• Your health and the health of the environment
depend on your knowledge of biology.
• Biotechnology offers great promise but also
raises ethical issues.
• Biology presents many unanswered questions.
What Do You Think?
• Many medications used to treat human illnesses
are based on substances found in other
organisms. How might a decrease in biodiversity
affect medical treatments and/or future
discoveries?
• Mosquitos carry many different diseases that can
sicken and kill humans. Even mosquitos that are
not infectious are considered pests. However,
they are also food for many species. If we had a
way in which to rid the earth of mosquitos, do
you think we should?