Chapter 1: Characteristics of Life, Evolution, Process of Science, and Biodiversity (Lecture Notes)

Vocabulary flashcards covering key terms and definitions from the lecture notes on life, its organization, evolution, taxonomy, scientific method, and contemporary challenges.

Biology

The scientific study of life.

Life

The characteristic shared by living things: diversity overall, yet common basic features, elements, and adherence to physical and chemical laws.

Emergent properties

New, unique characteristics that arise at higher levels of biological organization.

Atom

Smallest unit of an element, composed of electrons, protons, and neutrons.

Molecule

Union of two or more atoms of the same or different elements.

Cell

The structural and functional unit of all living organisms.

Tissue

A group of cells with a common structure and function.

Organ

A structure composed of tissues functioning together for a specific task.

Organ System

Several organs working together to perform a broader function.

Organism

An individual; more complex organisms contain organ systems.

Species

A group of similar, interbreeding organisms.

Population

Members of the same species in a particular area.

Community

Interacting populations in a particular area.

Ecosystem

A community plus its physical environment; includes energy flow and chemical cycling.

Biosphere

Regions of Earth’s crust, water, and atmosphere inhabited by living organisms.

Homeostasis

Maintenance of internal conditions within certain boundaries; requires feedback control.

Metabolism

All chemical reactions that occur in a cell.

Energy

The capacity to do work; essential to maintain organization and life processes.

Photosynthesis

Process by which solar energy is converted into chemical energy (carbohydrates) by plants and some algae.

Energy flow

The passage of energy through an ecosystem from producers to consumers to decomposers; must have continual input from the sun.

Chemical cycling

reuse of nutrients within an ecosystem; chemicals are not used up when organisms die.

Producer

Organisms that capture solar energy and convert it to chemical energy (through photosynthesis).

Consumer

Organisms that obtain energy by consuming other organisms.

Decomposer

Organisms that break down dead matter and recycle nutrients.

Feedback system

Mechanisms that monitor and adjust internal conditions to maintain homeostasis.

Reproduction

Process by which organisms produce offspring and pass on genetic information (genes) to the next generation.

Genes

Units of hereditary information composed of DNA.

DNA

Deoxyribonucleic acid; molecule that carries genetic information.

Adaptation

Modification that makes an organism better suited to its environment.

Evolution

Change in a population over time to become better suited to the environment.

Common descent with modification

All living things descended from a shared ancestor, with changes over time.

Natural selection

Mechanism by which environmental pressures favor certain traits, increasing their frequency; mutations provide variation.

Mutation

Alterations in DNA that introduce variation among population members.

Evolutionary tree

A diagram tracing the ancestry of life back to a common ancestor.

Taxonomy

Discipline that identifies, names, and classifies organisms.

Systematics

Study of evolutionary relationships among organisms.

Domain

Highest taxonomic rank; includes Archaea, Bacteria, and Eukarya.

Archaea

Unicellular prokaryotes that often live in extreme environments; lack a membrane-bound nucleus.

Bacteria

Unicellular prokaryotes found in diverse environments; include many on skin and in the gut; lack a nucleus.

Eukarya

Domain containing all eukaryotic organisms; cells with a membrane-bound nucleus.

Protista

Kingdom within Eukarya; algae, protozoans, slime molds, water molds; mostly single-celled.

Fungi

Kingdom including molds, mushrooms, yeasts; mainly multicellular; absorb food.

Plantae

Kingdom of multicellular, usually photosynthetic plants.

Animalia

Kingdom of multicellular animals that ingest food.

Binomial nomenclature

Universal Latin-based two-part name: genus (capitalized) + species (lowercase); both italicized.

Homo sapiens

Example of a binomial name for humans.

The Process of Science

Systematic method for gaining knowledge: observation, hypothesis, predictions/experiments, data collection with statistics, and conclusion.

Observation

Using senses to gather information about a phenomenon.

Hypothesis

Tentative, testable explanation developed from observations.

Prediction

A forecast about outcomes tested by experiments; uses deductive reasoning.

Experiment

Procedures designed to test a hypothesis; involves manipulating variables.

Independent variable

The factor deliberately tested in an experiment.

Control group

Group that is treated identically except for the absence of the experimental variable.

Test/Experimental group

Group exposed to the experimental variable.

Data

Results of experiments; should be observable and objective.

p-value

Probability value indicating the likelihood results occurred by chance; p < 0.05 is commonly considered significant.

Statistical significance

A result unlikely to be due to chance alone, as determined by statistical analysis.

Conclusion (in science)

Interpretation of data to determine whether the hypothesis was supported or rejected; findings may be published and peer-reviewed.

Theory

A well-supported explanation that links together multiple hypotheses and a broad range of observations and data.

Law/Principle

Widely accepted statements that describe natural phenomena and are resistant to change.

Biodiversity

Total number and relative abundance of species, genetic variation, and ecosystems; estimated up to 8.7 million species, with fewer than 2.3 million named.

Extinction

Death of the last member of a species or higher group.

Habitat loss

Destruction or alteration of environments, leading to biodiversity loss and ecosystem disruption.

Emerging diseases

New or increasing diseases due to factors like exposure, behavior changes, globalization, or pathogen mutation (examples: H5N1, H7N9, SARS, Ebola).

Climate change

Long-term changes in Earth's climate caused by human activities; increased CO2 from burning fossil fuels and deforestation leads to global warming.

Greenhouse effect

Warming of Earth due to heat-trapping gases in the atmosphere.

Global warming

Long-term increase in Earth's average surface temperature due to increased greenhouse gases.