Chapter 1: Principles of Life
Terms in this set (61)
(1) In evolutionary biology, a particular structure, physiological process, or behavior that makes an organism better able to survive and reproduce. Also, the evolutionary process that leads to the development or persistence of such a trait. (2) In sensory neurophysiology, a sensory cellâ€™s loss of sensitivity as a result of repeated stimulation.
Requiring molecular oxygen, O2. (Contrast with anaerobic.)
Occurring without the use of molecular oxygen, O2. (Contrast with aerobic.)
Unicellular organisms lacking a nucleus and lacking peptidoglycan in the cell wall. Once grouped with the bacteria, archaeans possess distinctive membrane lipids.
Unicellular organisms lacking a nucleus, possessing distinctive ribosomes and initiator tRNA, and generally containing peptidoglycan in the cell wall. Different bacterial groups are distinguished primarily on nucleotide sequence data.
A taxonomic naming system in which each species is given two names (a genus name followed by a species name).
The region that supports living organisms on Earth, extending about 23 km from the abyssal depths of the oceans into the stratosphere (an upper portion of the atmosphere).
The simplest structural unit of a living organism. In multicellular organisms, many individual cells serve as the building blocks of tissues and organs.
The catabolic pathways by which electrons are removed from various molecules and passed through intermediate electron carriers to O2, generating H2O and releasing energy.
An organelle bounded by a double membrane containing the enzymes and pigments that perform photosynthesis. Chloroplasts occur only in eukaryotes.
The assemblage of interacting individuals of different species within a particular geographic area.
Experimental design in which data from various unmanipulated samples or populations are compared, but in which variables are not controlled or even necessarily identified. (Contrast with controlled experiment.)
The interacting parts of a biological system.
A system in which the interactions among components are expressed as mathematical functions.
An experiment in which a sample is divided into groups whereby experimental groups are exposed to manipulations of an independent variable while one group serves as an untreated control. The data from the various groups are then compared to see if there are changes in a dependent variable as a result of the experimental manipulation. (Contrast with comparative experiment.)
Quantified observations about a system under study.
DNA (deoxyribonucleic acid)
The fundamental hereditary material of all living organisms. In eukaryotes, stored primarily in the cell nucleus. A nucleic acid using deoxyribose rather than ribose.
(1) An independent structural element within a protein. Encoded by recognizable nucleotide sequences, a domain often folds separately from the rest of the protein. Similar domains can appear in a variety of different proteins across phylogenetic groups (e.g., â€œhomeobox domainâ€; â€œcalcium-binding domainâ€). (2) In phylogenetics, the three monophyletic branches of life (Bacteria, Archaea, and Eukarya).
One or more organisms and the abiotic and biotic environment with which they interact.
In general, shorthand for â€œecological system.â€ Often used more specifically to refer to an ecological community and its abiotic environmental context.
The theory that the eukaryotic cell evolved via the engulfing of one prokaryotic cell by another.
One of the three domains of life; organisms made up of one or more eukaryotic cells. (See also eukaryotes.)
Organisms whose cells contain their genetic material inside a nucleus. Includes all life other than the viruses, archaea, and bacteria. (Contrast with prokaryotes.)
Any gradual change. Most often refers to organic or Darwinian evolution, which is the genetic and resulting phenotypic change in populations of organisms from generation to generation. (Contrast with speciation.)
In regulatory systems, information about the relationship between the set point of the system and its current state (Contrast with feedforward information).
A unit of heredity. Used here as the unit of genetic function which carries the information for a polypeptide or RNA.
The complete DNA sequence for a particular organism or individual.
A tentative answer to a question, from which testable predictions can be generated. (Contrast with theory.)
An ecological system consisting of multiple ecological communities within a geographical area larger than the area occupied by a single community.
An organelle in eukaryotic cells that contains the enzymes of the citric acid cycle, the respiratory chain, and oxidative phosphorylation.
A species that is widely studied experimentally to understand general principles about biology.
A change in the genetic material not caused by recombination.
An observation about nature, obtained outside of a formal hypothesis-testing context, that provides the basis for further investigation.
The differential contribution of offspring to the next generation by various genetic types belonging to the same population. The mechanism of evolution proposed by Charles Darwin.
In a regulatory system, a type of control that acts to reduce differences that arise between the level of a controlled variable and its set-point level. It tends to stabilize the controlled variable at a level close to the set-point level. (Contrast with positive feedback.)
A polymer made up of nucleotides, specialized for the storage, transmission, and expression of genetic information. DNA and RNA are nucleic acids.
The basic chemical unit in nucleic acids, consisting of a pentose sugar, a phosphate group, and a nitrogen-containing base.
(1) In cells, the centrally located compartment of eukaryotic cells that is bounded by a double membrane and contains the chromosomes. (2) In the brain, an identifiable group of neurons that share common characteristics or functions.
In statistics, the premise that any differences observed in an experiment are simply the result of random differences that arise from drawing two finite samples from the same population.
A body part, such as the heart, liver, brain, root, or leaf, that is composed of two or more tissues integrated to perform a distinct function.
Any of the membrane-enclosed structures within a eukaryotic cell. Examples include the nucleus, endoplasmic reticulum, and mitochondria.
Any living entity.
An interrelated and integrated group of tissues and organs that work together in a physiological function.
Metabolic processes carried out by green plants and cyanobacteria, by which visible light is trapped and the energy used to convert CO2 into organic compounds.
A graphic representation of lines of descent among organisms or their genes.
A group of individuals of the same species that live, interact, and reproduce together in a particular geographic area.
In a regulatory system, a type of control that acts to increase differences that arise between the level of a controlled variable and its set-point level. The period of amplifying deviation is followed by a period in which stabilization is restored in most biological systems. (Contrast with negative feedback.)
The ways in which the components of a biological system interact (e.g., protein synthesis, nutrient metabolism, grazing).
Unicellular organisms that do not have nuclei. (Contrast with eukaryotes.)
Long-chain polymer of amino acids with twenty different common side chains. Occurs with its polymer chain extended in fibrous proteins, or coiled into a compact macromolecule in enzymes and other globular proteins.
The immediate genetic, physiological, neurological, and developmental explanations for the advantages of an adaptation.
To assign numerical values to observations through measurement.
A system that uses feedback information to maintain a physiological function or parameter at an optimal level. (Contrast with controlled system.)
A set of interacting parts in which neither the parts nor the whole can be understood without taking into account the interactions among the parts.
The understanding of a biological system through evaluation of its components and their interactions.
A far-reaching explanation of observed facts that is supported by such a wide body of evidence, with no significant contradictory evidence, that it is scientifically accepted as a factual framework. Examples are Newtonâ€™s theory of gravity and Darwinâ€™s theory of evolution. (Contrast with hypothesis.)
A group of similar cells organized into a functional unit; usually integrated with other tissues to form part of an organ.
tree of life
A term that encompasses the evolutionary history of all life, or a graphic representation of that history.
The historical explanations of the processes that led to the evolution of an adaptation.
In a controlled experiment, a factor that is manipulated to test its effect on a phenomenon.