Introduction to Biology: Themes, Organization, and Diversity

Comprehensive vocabulary flashcards covering the characteristics of life, levels of biological organization, taxonomy, branches of study, and scientific ethics as discussed in the lecture transcript.

Biology

The science that studies life.

Virology

A branch of biology that studies viruses, which exhibit some characteristics of living entities but lack others.

Properties of Life

A set of characteristics shared by all living organisms: order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation/homeostasis, energy processing, and evolution.

Chemotaxis

A process in which tiny bacteria move toward or away from chemicals.

Phototaxis

A process in which tiny bacteria move toward or away from light.

Positive response

Movement toward a stimulus.

Negative response

Movement away from a stimulus.

DNA (deoxyribonucleic acid)

The genetic material containing genes that is passed along to an organism's offspring during reproduction.

Adaptation

The "fit" of living organisms to their environment, which is a consequence of evolution by natural selection.

Homeostasis

The relatively stable internal environment required to maintain life, literally meaning "steady state."

Thermoregulation

A regulatory mechanism in which organisms regulate their body temperature, such as polar bears using thick fur and fat to withstand low temperatures.

Atom

The smallest and most fundamental unit of matter that retains the properties of an element, consisting of a nucleus surrounded by electrons.

Molecule

A chemical structure consisting of at least two atoms held together by a chemical bond.

Macromolecules

Large molecules typically formed by combining smaller units called monomers, such as DNA.

Organelles

Small structures that exist within cells and perform specialized functions; some contain aggregates of macromolecules surrounded by membranes.

Cell

The smallest fundamental unit of structure and function in living organisms.

Prokaryotes

Single-celled organisms that lack organelles surrounded by a membrane and do not have nuclei surrounded by nuclear membranes.

Eukaryotes

Organisms with cells that contain membrane-bound organelles and nuclei.

Tissues

Groups of similar cells carrying out the same function in multicellular organisms.

Organs

Collections of tissues grouped together based on a common function, present in both animals and plants.

Organ system

A higher level of organization consisting of functionally related organs, such as the circulatory system.

Organisms

Individual living entities, including single-celled microorganisms and multicellular individuals like trees.

Population

All the individuals of a species living within a specific area.

Community

The set of populations inhabiting a particular area, such as all the trees, flowers, and insects in a forest.

Ecosystem

All the living things in a particular area together with the abiotic, or non-living, parts of the environment.

Biosphere

The highest level of organization; the collection of all ecosystems on Earth, including land, water, and portions of the atmosphere.

Evolution

The process of gradual change during which new species arise from older species, serving as the source of life's diversity.

Carl Linnaeus

The scientist who in the $18\text{th}$ century first proposed organizing known species into a hierarchical taxonomy and developed the binomial naming system.

Taxonomic Hierarchy

The eight levels of organization for organisms: species, genus, family, order, class, phylum, kingdom, and domain.

Domain

The highest level of taxonomic hierarchy; the three recognized domains are Bacteria, Archaea, and Eukarya.

Extremophiles

Single-celled organisms, often belonging to the domain Archaea, that live in harsh environments like boiling hot springs.

Binomial Naming System

A naming system consisting of the capitalized genus name and the lower-case species name, both set in italics (e.g., $Homo\text{ }sapiens$).

Phylogenetic Tree

A diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits.

Carl Woese

The microbiologist who in the early $1970\text{s}$ proposed the domain as a new taxonomic level based on genetic relationships rather than morphology.

Molecular Biology

A sub discipline that studies biological processes at the molecular level, including interactions among DNA, RNA, and proteins.

Neurobiology

The study of the biology of the nervous system, also known as neuroscience.

Paleontology

A branch of biology that uses fossils to study life's history.

Forensic Science

The application of science to answer questions related to the law, such as analyzing hair, blood, or DNA evidence from crime scenes.

Bioethics

A field that defines guidelines for scientific practice, balancing benefits with potential harm and ensuring dignity and safety for research subjects.

HeLa cell line

An "immortal" cell line created without permission from the cervical cancer cells of Henrietta Lacks in $1951$, contributing to major medical discoveries.