bio ch1 sec1 and 2

section 1 The World of Biology section 2 Themes in Biology

Biology : The Science of Life

Biology - “the study of life”

the natural world

bacteria to elephants food to exerciseenvironment

bioethics - biology in context of society

Biology and You

Characteristics of Life

Life has changed since it first appeared on the planet, Today, biologist identify a living thing through

observation of shared characteristics.

Self-directed Organization

cell - basic unit of structure and function (organelles and biomolecules)

unicellular or multicellular

Organization

levels of organizationcells tissues organs organ system organism

population --> community -->ecosystem --> biome -->biosphere

stimulus-response

stimulus - causal event in environment

response - reaction to causal event

Response to Stimuli

responses in an organism which maintain stable internal conditions in a changing environment

light, temperature, water

Homeostasis

growth - increase in size

growth - increase in the number of cells through cell division

development - series of changes during growth due to cell specialization

Growth and Development

making more of ones own kind - species

asexual

sexual

Inherited set of instructions in the nucleic acids DNA or RNA

Reproduction

species change over time

mutation

variations in a population

differential survival due to “fitness”

Evolution

Energy required for each characteristic

metabolism - sum of chemical reactions to transform energy to a usable form

photosynthesis - respiration

provide material for growth and repair

Metabolism