Biol& 211: Cellular Biology - Characteristics of Life, Experimental Design, and Natural Selection

Vocabulary flashcards covering the characteristics of life, Pasteur's experiment, the central dogma, scientific method, and Darwinian natural selection from Biol& 211 lecture notes.

Five Fundamental Characteristics of Life

The five defining attributes shared by all living organisms: being composed of membrane-bound cells, the capacity for replication, processing hereditary and environmental information, acquiring and utilizing energy to stay alive, and continuous evolution of populations.

Spontaneous Generation

The hypothesis that living organisms can arise spontaneously from nonliving matter, which was disproved by Louis Pasteur's experiments.

Pasteur's Swan-Necked Flask Experiment

An experiment testing the origin of cells where boiled nutrient broth remained free of living organisms in a swan-necked flask because airborne cells became trapped in the neck, confirming that cells arise only from preexisting cells.

Cell Theory

The biological principle stating that all organisms are made of membrane-bound cells and that all cells present in a multicellular organism have descended from preexisting cells connected by a common lineage.

Chemical Evolution

The scientific process explaining how life originally arose from non-life early in Earth's history.

DNA Double Helix

The structure proposed by James Watson and Francis Crick consisting of two strands joined by specific interactions between base pairs ($A$ pairing with $T$, and $C$ pairing with $G$), which preserves genetic information and allows DNA replication.

Central Dogma

The principle describing the directional flow of genetic information inside cells: DNA is transcribed into messenger RNA (mRNA), which is then translated into proteins that carry out cellular tasks and determine physical traits.

Adenosine Triphosphate (ATP)

The chemical energy molecule that organisms must acquire or synthesize to fuel intracellular chemical reactions and maintain cellular life.

Evolution

A change in the characteristics of a population over time, which demonstrates that species are related to one another and change through generations.

Population

A group of individuals belonging to the same species that live in the same geographic area at the same time.

Natural Selection

The mechanism of evolution occurring when individuals in a population possess heritable variation and certain versions of those traits allow individuals to survive and reproduce more successfully in a particular environment.

Scientific Theory

A framework that explains a broad class of phenomena supported by substantial evidence, typically consisting of a pattern (observations about the natural world) and a process (the mechanism causing that pattern).

Null Hypothesis

A statement specifying what should be observed in an experiment or study when the primary hypothesis being tested is incorrect.

Pedometer Hypothesis

The hypothesis that Saharan desert ants calculate their distance from the nest using an internal pedometer that tracks stride number and stride length.

Typological Thinking

The philosophical viewpoint proposed by Plato stating that every organism is an example of an unchanging, perfect type created by a divine being, treating individual variation as trivial distortion.

Scale of Nature

Aristotle's organization of living organisms into a rigid hierarchy or ladder based on increasing size and complexity, with lower organisms at the bottom and humans at the top.

Historical Models of Diversity of Life

The conceptual progression of evolutionary thinking from Plato's typological thinking, to Aristotle's scale of nature, to Lamarck's change through time on a scale of nature, to Darwin and Wallace's model of change through time coupled with common ancestry.

Descent with Modification

Darwin's description of evolution, embodying the predictions that species change through time and that all species are related by common ancestry.

Darwin's Four Postulates

The four criteria of natural selection: variation exists among individuals in a population; some traits are heritable; survival and reproductive success are variable; and individuals with traits that confer higher survival and reproduction are a non-random subset of the population.

Biological Fitness

The relative ability of an individual to survive and produce viable offspring compared to other individuals in that population.

Adaptation

A heritable trait that increases the biological fitness of an individual in a specific environment relative to individuals lacking that trait.

Vestigial Trait

A reduced or incompletely developed structure that has no function or reduced function in an organism, but is clearly homologous to functioning structures in closely related or ancestral species.

Transitional Feature

A trait in a fossil organism that exhibits an intermediate state between ancestral (older) and derived (younger) forms, providing evidence for change through time.

Homology

A structural, developmental, or genetic similarity between different species resulting from shared inheritance from a common ancestor.

Necking Hypothesis in Giraffes

An alternative hypothesis proposing that giraffes evolved long necks through sexual selection rather than food competition, because males utilize their long necks and heavy skulls as weapons to strike each other in combat for female access.

Melanocortin-1 Receptor (Mc1r) Polymorphism

A genetic system in pocket mice where alleles $D$ and $d$ differ by four amino acids; genotypes $DD$ and $Dd$ confer dark coat color favored on dark volcanic rock substrates, while the $dd$ genotype confers light coat color favored on light granite substrates.