Chapter 1 An Introduction To Life On Earth Flashcards
Biodiversity
The diversity of living organisms; measured as the variety of different species, the variety of different alleles in a gene pool, or the variety of different community interaction in a ecosystem.
Cell
The smalles unit of life, consisting, at a minimum, of an outer membrane that encloses a watery medium containing organic molecules, including genetic material composed of DNA
Community
All the interacting populations within an ecosystem.
Conclusion
The final operation in the scientific method; a decision made abou the validity of a hypothesis on the basis of experimental evidence.
Control
The portion of an experiment in which all possible variables are held constant; in contrast to the “experimental” portion, in which a particular varibale is altered.
Deoxyribonucleic Acid (DNA)
A molecule composed of deoxyribose nucleotides; contains the genetic information of all cells.
Energy
The capacity to do work.
Evolution
(1) The theory that all species are related by common ancestry and have changed over time; (2) Any change in the proportions of different genotypes in a population from one generation to the next.
Experiment
A fifth operation in the scientific method; the testing, by further observations, of a prediciton generated by a hypothesis, leading to a conclusion.
Gene
A unit of heredity that encondes the information needed to specify the amino acid sequence of protiens and hence particular traits; a functional segment of DNA located at a particular place on a chromosone.
Hypothesis
The third operation in the scientific method; a supposition based on a pervious observations that is offered as an explanation for the observed phenomenon and is used as the basis for further observations or experiments.
Natural Selection
The process in which unqeual survival and reproduction of organisms, favoring indiviuals with particular traits, causes those traits to become increasingly common in a population.
Observation
The first operation in the scientific method; noting of a specific phenomenon, leading the formulation of a question.
Organ
A structure (such as the liver, kidney, or skin) composed of two or more distinct tissue types that function together.
Organism
An individual living thing.
Photosynthesis
The complete series of chemical reactions in which the energy of light is used to synthesize high-energy organic molecules, normally carbohydrates, from low-energy inorganic molecules, normally carbon dioxide and water.
Population
All the members of a species that occupy a particular area at the same time.
Prediction
A fourth operation in the scientific method; a statement describing an observable outcome that would occur if a particular hypothesis were true.
Question
The second operation in the scientific method; a query that identifies a particular aspect of an observation that a scientist wishes to explain.
Scientific Method
A rigorous procedure for making observaions of specific phenomena and searching for the order underlying those phenomena; consists of six operations: observation, question, hypothesis, prediction, experiment, conclusion.
Scientific Theory
A general explanation of natural phenomena devoloped through extensive and reproducible observations; more general and reliable than a hypothesis.
Species
The basic unit of taxonomic classification, consisting of a group of populations that evolves independently. In sexually reproducing organisms, a species can be defined as a population or series of populations of organisms that interbreed frely with one another under natrual conditions but that do not interbreed with members of other species.
Tissue
A group of (normally similar) cells that together carry out a specific function; for example, muscle; may include extracellular material produced by its cells.
Variable
A condition, particularly in a scientific experiment, that is subject to change.
