Chapter 1The Science of Life

The Study of LifeBiology: the study of living things

Some Fields of Biology: entomology (insects) parasitology (parasites) microbiology (bacteria) ornithology (birds) herpetology (reptiles)

Six Major Themes of BiologyCell structure and functionStability and homeostasisReproduction and inheritanceEvolutionInterdependence of organismsMatter, energy, and organization

Cell Structure and FunctionCells are the basic unit of life

All organisms are made of and develop from cells

Unicellular OrganismsOrganisms composed of only one cell

Examples: bacteria and protists

Multicellular organismsOrganisms 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

DifferentiationIn multicellular organisms, cells become different as they grow and develop

After fertilization, cells divide and will eventually become specialized

Stability and HomeostasisLiving things maintain stable internal conditions

Examples: body temperature, water content, electrolytes

Reproduction and InheritanceOrganisms transmit hereditary information to their offspring

DNA (deoxyribonucleic acid)

Gene: a short segment of DNA that contains instructions for a single trait

Sexual ReproductionProduction of offspring from the combination of genetic material from two parent organisms

Example: sperm + egg = zygote

Asexual ReproductionDoesnt require two different organisms

One cell gives rise to two cells

Example: binary fission in bacteria and protists

EvolutionEvolution= 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 SelectionDriven by competition among individuals for resources

Individuals that can survive will be able to mate

Traits are inherited by offspring

Interdependence of OrganismsEcology: the study of the interactions of organisms and their environment

Ecosystems= environmental communities

Fragile EnvironmentsAll life is interconnected

When one aspect of the environment is harmed, it will have a negative impact on the whole ecosystem

Matter, Energy, and OrganizationAlmost all energy on Earth comes from the sun

Photosynthesis- plants capture energy from the sun use it to manufacture glucose

AutotrophsOrganisms that make their own food

self-feeders

Example: plants

HeterotrophsOrganisms that must take in food to meet their energy needs

other-feeders

Examples: rabbits, coyotes, bears

ConclusionBiology 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