Chapter 1Chapter 1

The Science of LifeThe Science of Life

The Study of LifeThe Study of Life

• Biology: the study of living thingsBiology: the study of living things

• Some Fields of Biology: entomology (insects)Some Fields of Biology: entomology (insects)

parasitology (parasites)parasitology (parasites)

microbiology (bacteria)microbiology (bacteria)

ornithology (birds)ornithology (birds)

herpetology (reptiles)herpetology (reptiles)

Six Major Themes of BiologySix Major Themes of Biology

• Cell structure and functionCell structure and function

• Stability and homeostasisStability and homeostasis

• Reproduction and inheritanceReproduction and inheritance

• EvolutionEvolution

• Interdependence of organismsInterdependence of organisms

• Matter, energy, and organizationMatter, energy, and organization

Cell Structure and FunctionCell Structure and Function

• Cells are the basic Cells are the basic unit of lifeunit of life

• All organisms are All organisms are made of and made of and develop from cellsdevelop from cells

Unicellular OrganismsUnicellular Organisms

• Organisms Organisms composed of only composed of only one cellone cell

• Examples: bacteria Examples: bacteria and protistsand protists

Multicellular organismsMulticellular organisms

• Organisms Organisms composed of more composed of more than one cellthan one cell

• May be highly May be highly complexcomplex

• Examples: plants Examples: plants and animalsand animals

Facts about cells:Facts about cells:

• Cells are highly organizedCells are highly organized

• Contain specialized structuresContain specialized structures

• There are many different kinds of cellsThere are many different kinds of cells

• Contain genetic materialContain genetic material

DifferentiationDifferentiation

• In multicellular organisms, cells In multicellular organisms, cells become different as they grow and become different as they grow and developdevelop

• After fertilization, cells divide and will After fertilization, cells divide and will eventually become specializedeventually become specialized

Stability and HomeostasisStability and Homeostasis

• Living things Living things maintain stable maintain stable internal conditionsinternal conditions

• Examples: body Examples: body temperature, water temperature, water content, content, electrolyteselectrolytes

Reproduction and Reproduction and InheritanceInheritance

• Organisms transmit hereditary Organisms transmit hereditary information to their offspringinformation to their offspring

• DNA (deoxyribonucleic acid)DNA (deoxyribonucleic acid)

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

Sexual ReproductionSexual Reproduction

• Production of Production of offspring from the offspring from the combination of combination of genetic material genetic material from two parent from two parent organismsorganisms

• Example: Example:

sperm + egg = zygotesperm + egg = zygote

Asexual ReproductionAsexual Reproduction

• Doesn’t require Doesn’t require two different two different organisms organisms

• One cell gives rise One cell gives rise to two cellsto two cells

• Example: binary Example: binary fission in bacteria fission in bacteria and protistsand protists

EvolutionEvolution

• Evolution= a genetic change in a Evolution= a genetic change in a population over a long period of timepopulation over a long period of time

• Natural selection: organisms that Natural selection: organisms that have favorable traits will survive have favorable traits will survive better and pass those traits on to better and pass those traits on to their offspringtheir offspring

Evolution by Natural Evolution by Natural SelectionSelection• Driven by competition Driven by competition

among individuals for among individuals for resourcesresources

• Individuals that can Individuals that can survive will be able to survive will be able to mate mate

• Traits are inherited by Traits are inherited by offspringoffspring

Interdependence of Interdependence of OrganismsOrganisms• Ecology: the study Ecology: the study

of the interactions of the interactions of organisms and of organisms and their environmenttheir environment

• Ecosystems= Ecosystems= environmental environmental communitiescommunities

Fragile EnvironmentsFragile Environments

• All life is All life is interconnectedinterconnected

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

Matter, Energy, and Matter, Energy, and OrganizationOrganization

• Almost all energy on Earth comes Almost all energy on Earth comes from the sunfrom the sun

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

AutotrophsAutotrophs

• Organisms that Organisms that makemake their own their own foodfood

• ““self-feeders”self-feeders”

• Example: plantsExample: plants

HeterotrophsHeterotrophs

• Organisms that Organisms that must take in food to must take in food to meet their energy meet their energy needsneeds

• ““other-feeders”other-feeders”

• Examples: rabbits, Examples: rabbits, coyotes, bearscoyotes, bears

ConclusionConclusion

• Biology is the Biology is the study of life, study of life, ranging from the ranging from the study of unicellular study of unicellular organisms to the organisms to the study of global study of global interactions interactions among millions of among millions of organismsorganisms

All forms of life deserve All forms of life deserve protection and respectprotection and respect