biological science 1

Theory

Observations that are supported by a wide body of evidence. (ex: what are organisms made of?)

hypothesis

a testable statement to explain a phenomenon or a set of observations.

prediction

A statement that forecasts what would happen in a test situation if the hypothesis were true. Must be correct for hypothesis to be true.

cell theory

All organisms are made of cells and all cells come from preexisting cells.

micoscope

a instrument that magnifies small things. Used by van Leeuwenhoek to observe cells for the first time (17th century)

cell

A highly organized compartment that is bound by a thin flexible structure called a plasma membrane and that contains concentrated chemicals in an aqueous (watery) solution.

Spontaneous generation

The hypothesis that cells arose spontaneously from nonliving materials. Disproved by pasteur's swan necked experiment.

evolution

A change in the characteristics of a population over time. It means that species are not independent and unchanging entities, but are related to one another and can change over time.

descent with modification

The characteristics of species can be modified from generation to generation.

natural selection

Occurs when 1) Individuals have heritable traits and 2) in particular environments, certain versions of these traits help individuals survive better.

heritable trait

Traits that can be passed onto offspring

Population

A group of individuals of the same species living in the same area at the same time.

Fitness

The ability of an individual to produce viable offspring

adaptation

a trait that increases the fitness of an individual in a particular environment

artificial selection

changes in populations that occur when humans select certain individuals to produce the most offspring

speciation

when natural selection causes populations of one species to diverge and form new species.

rRna

small subunit ribosomal RNA. Made up of ribonucleotides symbolized by A, U, C, and G. Used to fill out the phylogenetic tree.

tree of life

Phylogenetic tree. Shows the relationship between species using rRNA. Also known as "a family tree of organisms."

taxonomy

The effort to name and classify organisms.

taxon (plural: taxa)

Any named group in taxonomy.

binomial nomenclature

Classification system in which each species is assigned a two-part scientific name. Part 1) Genus 2) species.

scientific name

an organism's genus and species designation. Always italicized. (also binomial nomenclature)

domain

A taxonomic category created to accurately describe the three major branches of life: the Bacteria, the Archaea, and the Eukarya

kingdom

Archaic way of classifying organisms. Now we use the phylogenetic tree.

Phylum

The term used to refer to major lineages within each domain. 30-35 right now, each distinguished by distinctive aspects of body structure and gene sequences. Ex: mollusks (clams, squid, octopi).

genus (plural: genera)

made up of a closely related group of species. First of the two-part scientific name. Homo for Homo sapiens

species

second term in the scientific name, identifies the species. Ex: sapiens for Homo sapiens.

prokaryote

A unicellular organism that lacks a nucleus. The vast majority of bacterial and archaeal cells are prokaryotes.

eukaryote

cells that have a nucleas. Many of these are multicellular. Name = true kernel.

phylogeny

The evolutionary relationships of all organisms. Studied by Woese and others by using rRNA.

phylogenetic tree

the tree of life., A family tree that shows the evolutionary relationships thought to exist among groups of organisms.

hypothesis testing

1) State hypothesis 2) Alternative hypothesis 3) observational or experimental study 4) interpret the results 5) if predictions are accurate hypothesis is supported 6) if not, then modify or discard hypothesis.

null hypothesis

A hypothesis that specifies what the results of an experiment will be if the main hypothesis being tested is wrong. Often states that there will be no difference between experimental groups.

observational study

A study based on data in which no manipulation of factors has been employed.

experimental study

A study in which the researcher manipulates one of the variables and tries to determine how the manipulation influences other variables.

control group

checks for factors other than the one being tested that might influence the experiment's outcome.

hornet in the _

green green grass