biology

chapter 1

atom

all living structures are composed of these particles; smallest chemical unit of a type of pure substance ex: carbon atom

molecules

a group of joined atoms ex: DNA

Organelles

membrane-bound structures that have a specific function within a cell ex: chloroplast

tissues

a collection of specialized cells that function in a coordinated fashion (only in multicellular life) ex: epidermis of leaf

organs

structure consisting of specialized cells taht function in a coordinated fashion (only in multicelllurlar life) ex epidermis of leaf

organ systems

organs connected physically or chemically that function together (multicellular life only) ex: above ground part of plant

population

a group of the same species of organism living in the same place and time ex:multiple trees

community

all populations that occupy the same region ex: all populations in a savanna

ecosystem

the living and nonliving components of an area ex: the savanna

biosphere

the global ecosystem; the parts of the planet and its atmosphere where life is possible

emergent properties

explain why structural organization is closely tied to function. new functions taht arise from physical and chemical interactions among a systems components something not evident from the parts themselves ex: memory

producers

make their own food by extracting energy and nutrietns from nonliving sources ex:plants

consumers

obtain energy and nutrients by eating other organisms, living or dead; heterotrophs ex humans

decomposers:

heterotrophs that absorb energy and nutrients from wastes or dead organisms. recycle nutrients tot he nonliving enviornment ex: fungi

autotrophs

producers

heterotrophs

consumers

homeostatsis

the state of internal constancy

reproduction

making other individuals similar to themselves by transmitting DNA from genration to generation

asexual reproduction

genetic information comes from only one parent, and all offspring are virtually identical. e.g., bacteria (one celled organisms)

sexual reproduction

genetic amterial from two parents unites to form an offspring, which has a new combination of inherted tratis. results in diversity in a population. genetic ddiversity enhances chance that individuals will survive even if conditions change.

evolution

a change in the genetic makeup of a population over multiple generations

adaptation

an inherited characteristic or behavior that enables an organism to survive and reproduce successfully in its environment.

natural selection

the enhanced reproductive success of certain individuals from a population based on inherited characteristics.

taxonomy

the science of naming and classifying organisms

species

designates a distinctive type of organism

genus

denotes the unique scientific name of each human (first word in the two word descriptor) (always capitalized)

domains

broadest taxonomic category. bacteria, archaea, and eukarya

kingdoms

next broadest taxonomic category,

charles darwin

introduced the theory of evolution by natural selection.

scientific method

a systematic approach to understanding the natural world based on evidence and testable hypotheses

hypothesis

tentavie explanation for one or more observations must be testable.

predicitions

written as an if-then statement. anticipated outcome of the test of a hypothesis

peer review

evaluation of scientific results by experts before publication in a journal

experiemtn

test of a hypothesis under controlled conditions.

sample size

number of subjects in each experimental group

variable

any changeable element in an experiment.

independent variable

a factor that is hypothesized to influence a dependent variable.

dependent variable

response taht may be under the influence of an independent variable.

standardized variable

any factor held constant for all subjects in an experiment

control

untreated group used as a basis for comparison with a treated group in an experiment

placebo

inert substance sometimes administered to an experimental control group

statistical significance

unlikely to be attributed to chance.

theory

well supported scientific explanation