Themes of Biology & Science as a Process (Video Notes)

Vocabulary flashcards covering key terms from the lecture notes on themes of biology, the scientific method, domains, cell theory, and taxonomy.

Theory

A well-supported explanation of natural phenomena, based on a large amount of evidence.

LUCA (Last Universal Common Ancestor)

The most recent common ancestor of all current life on Earth.

Descent with modification

Darwin’s idea that lineages change over time as offspring inherit changes from ancestors.

Natural selection

The mechanism of evolution where differential survival and reproduction favor certain heritable traits.

Domain

The highest taxonomic rank; the three domains are Bacteria, Archaea, and Eukarya.

Bacteria

A domain of prokaryotic organisms lacking a true nucleus; simple cellular organization.

Archaea

A domain of prokaryotes distinct from bacteria, often found in extreme environments.

Eukarya

A domain consisting of organisms with complex cells that have a nucleus.

Kingdoms (within Eukarya)

Major taxonomic groups within Eukarya, including Plantae, Animalia, Fungi, and Protista.

Plantae

Kingdom of multicellular, mostly photosynthetic organisms.

Animalia

Kingdom of multicellular, heterotrophic animals.

Fungi

Kingdom of organisms that decompose and absorb nutrients.

Protista

A diverse, informal kingdom of mostly single-celled eukaryotes.

Hypothesis

A testable educated guess about a relationship between variables.

Null hypothesis

The default statement of no effect or relationship; tested against data.

Prediction

A specific expected outcome used to test a hypothesis.

If… then…

A conditional format for expressing a testable prediction.

Scientific method

Process: ask questions, form hypotheses, test with experiments, analyze data, draw conclusions, publish.

Independent variable (IV)

The variable deliberately changed by the researcher.

Dependent variable (DV)

The variable measured in response to changes in the IV.

Experimental control

A baseline condition used for comparison to isolate the IV’s effect.

Open system

A system in which matter and energy can pass between the system and surroundings.

Emergent properties

New properties that arise at higher levels of organization, not present in individual parts.

Hierarchy of life / Levels of organization

Organization from simple to complex: molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere.

Cell theory

All living things are made of cells; cells come from preexisting cells; cell theory contributions by Schleiden, Schwann, and Hooke.

Prokaryotic

Cells lacking a true nucleus and many organelles; DNA in a nucleoid region.

Eukaryotic

Cells with a true nucleus and membrane-bound organelles.

Cell

The basic unit of life; smallest unit that can perform all vital functions.

DNA

Deoxyribonucleic acid; universal genetic material that stores hereditary information.

Homeostasis

Maintenance of internal stability through regulatory processes.

Negative feedback

A regulatory loop that returns a system toward a set point.

Positive feedback

A regulatory loop that amplifies a change, often leading to a new state.

Taxonomy

The science of naming, describing, and classifying organisms.

Domain (rank)

Highest taxonomic rank; groups life into Bacteria, Archaea, and Eukarya.

Species

The most specific taxonomic rank; organisms that can interbreed to produce fertile offspring.