Biology Lecture Review: Scientific Method, Gene Expression, and Evolution

Flashcards covering key vocabulary from the lecture notes on Scientific Method, Gene Expression, Evolutionary Thought, Hardy-Weinberg Equilibrium, Mechanisms and Evidence of Evolution, Types of Natural Selection, Extinction, Speciation, and Patterns of Evolution.

Independent Variable

The factor that is manipulated by the researcher.

Dependent Variable

The measured response to the manipulation.

Standardized Variables

Factors kept constant to avoid confounding.

Control Group

Used as a baseline; helps show whether the independent variable has an effect.

Placebo

An inactive treatment used to control for psychological effects.

Transcription

The process of DNA converting to mRNA, occurring in the nucleus.

Translation

The process of mRNA converting to protein, occurring at ribosomes.

Missense Mutation

A type of mutation that changes one amino acid, which can alter protein function.

Nonsense Mutation

A type of mutation that introduces a stop codon, resulting in a truncated protein.

Frameshift Mutation

A type of mutation (insertion/deletion) that shifts the reading frame.

Duplication/Insertion Mutation

A type of mutation where extra DNA segments are added.

Darwin

Proposed natural selection as the mechanism of evolution and published On the Origin of Species.

Lamarck

Believed in the inheritance of acquired traits.

Hardy-Weinberg Equilibrium

A state where allele and genotype frequencies in a population remain constant across generations under specific conditions (large population, random mating, no mutation, no migration, no selection).

Hardy-Weinberg Allele Frequency Equation

p + q = 1, where p and q are the frequencies of two alleles.

Hardy-Weinberg Genotype Frequency Equation

p

p

2

• 2pq + q

q

2

= 1, where p

p

2

, 2pq, and q

q

2

represent the frequencies of the three possible genotypes.

Natural Selection

Individuals with advantageous traits survive and reproduce more successfully.

Genetic Drift

Random changes in allele frequency, more impactful in small populations, and reduces genetic variation.

Bottleneck Effect

Occurs when a population is drastically reduced, and the survivors do not represent the original gene pool.

Founder Effect

Occurs when a new population is formed by a few individuals, leading to alleles being over or underrepresented.

Homology

Traits inherited from a common ancestor (e.g., bat wing and human arm).

Analogy

Refers to similar function but different origin (e.g., shark fin and dolphin flipper).

Vestigial Structures

Structures that were once useful but are now reduced (e.g., human tailbone).

Relative Dating

A dating method where lower rock layers indicate older age.

Radiometric Dating

A direct dating method that uses isotopes (e.g., C-14).

Directional Selection

Favors one extreme phenotype (e.g., dark moths on dark trees).

Stabilizing Selection

Favors the average phenotype (e.g., birth weight in humans).

Disruptive Selection

Favors both extreme phenotypes (e.g., beak size in finches).

Background Extinction

Ongoing, low-level extinction balanced by speciation.

Mass Extinction

A sudden, global event that wipes out many species at once.

Biological Species Concept

Defines species as interbreeding populations that produce viable offspring.

Sympatric Speciation

New species arise without geographic separation (e.g., via behavior, timing).

Descent with Modification

The principle that species share common ancestors, but traits change over time.

Punctuated Equilibrium

A model of evolution characterized by long periods of stability interrupted by short, rapid bursts of change.

Gradualism

A model of evolution characterized by slow, continuous change.

Adaptive Radiation (Darwin's Finches)

A process where a single species evolves into multiple new species to fill different ecological niches, exemplified by Darwin's Finches.

Microevolution (Plasmodium drug resistance)

Evolutionary change within a species or small group of organisms, especially over a short period, as seen in Plasmodium developing drug resistance.