what is life, chapter 1 lesson 1 - science
stimulus
a change in an organism's surroundings that causes the organism to react
response
a reaction to a stimulus
controlled experiment
a scientist carries out a series of tests that are identical in every respect except for one factor
biology
bio = life, logy = study of
the 6 characteristics of living things
cellular organization, contain similar chemicals, use energy, respond to their surroundings, grow and develop, and reproduce
the 4 needs of living things
food, water, living space and stable internal conditions
chemicals of life
water, proteins, lipids, carbohydrates, nucleic acid
unicellular
single-celled organisms like bacteria
a cell
the basic unit of structure and function in an organism
metabolism
the combination of chemical reactions through which an organism builds up or breaks down materials
homeostasis
the maintenance of stable internal conditions
spontaneous generation
the mistaken idea that living things can arise from nonliving sources
development
the process of change that occurs during an organisms life, producing a more complex organism
asexual reproduction
involves only one parent and produces offspring that are identical to the parent
sexual reproduction
involves two parents and combines their genetic material to produce a new organism that differs from both parents
organisms
living things
multicellular
organisms that are composed of many cells
heterotrophs
organisms that cannot make their own food
autotrophs
organisms that make their own food
living things arise from...
other living things through reproduction
