Evolution, Genetics, and the Scientific Method - Vocabulary Flashcards

Vocabulary flashcards covering core concepts from the lecture notes on science, evolution, genetics, and related methods.

Scientific Method

A systematic process for investigating phenomena that includes making observations, asking questions, forming hypotheses, testing with experiments, analyzing data, and drawing conclusions.

Observation

The act of noticing and describing phenomena without manipulating variables.

Hypothesis

A testable, educated guess that explains a phenomenon and can be tested by experimentation.

Theory (scientific)

A well-substantiated explanation of natural phenomena that has been repeatedly tested and confirmed through observation and experimentation.

Fact (scientific)

A statement or observation that is supported by evidence and widely accepted as true.

Coral Bleaching

Stress-induced loss of color in corals due to expulsion of their symbiotic algae (zooxanthellae), often driven by high water temperatures.

Zooxanthellae

Photosynthetic algae living in coral tissues that provide nutrients and color to corals.

Bleaching

The whitening of corals from loss of zooxanthellae or pigments, often caused by heat stress.

Hypothesis (Isolating)

A testable statement that connects cause and effect (e.g., If X is true, then Y will occur).

Independent Variable

The factor deliberately changed by the experimenter to test its effects.

Dependent Variable

The outcome or measurement collected in an experiment.

Control

A baseline or standard condition used for comparison with experimental treatments.

Observational Design

A study design where variables are not manipulated; data are collected as they occur.

Experimental Design

A study design that deliberately manipulates one or more variables to test causal effects.

Systematic Review

A comprehensive summary of related studies on a topic, following explicit methods to identify and evaluate evidence.

Meta-analysis

A statistical method to combine results from multiple studies to derive a overall conclusion.

Negative Data

Results that do not support the expected hypothesis but still inform and refine scientific understanding.

Mutation

A permanent change in DNA sequence; can be heritable if in germ cells.

Point Mutation

A single-nucleotide alteration in DNA.

Frameshift Mutation

Insertion or deletion of nucleotides that shifts the reading frame of a gene.

Chromosomal Mutation

Large-scale alterations in chromosome structure, such as deletions, duplications, translocations, or inversions.

Allele

Alternative form of a gene at a given locus.

Genotype

The genetic makeup of an organism at a particular gene or set of genes (the pair of alleles).

Phenotype

The observable physical or biochemical characteristics of an organism.

Homozygous

Having two identical alleles for a gene.

Heterozygous

Having two different alleles for a gene.

Dominant Allele

An allele whose phenotype is expressed in a heterozygote.

Recessive Allele

An allele whose phenotype is not expressed in a heterozygote.

Punnett Square

A diagram used to predict the genotypes and phenotypes of offspring from parental genotypes.

Mendel’s Law of Segregation

Alleles separate randomly into gametes during meiosis.

Mendel’s Law of Independent Assortment

Alleles of different genes assort independently during gamete formation.

Gene

A discrete unit of heredity located on a chromosome that codes for a protein or RNA.

Allele Frequency

The proportion of all alleles in a population that are of a given type.

Genotype Frequency

The proportion of individuals in a population with a given genotype.

Hardy-Weinberg Equilibrium

A null model where allele and genotype frequencies remain constant across generations in the absence of evolutionary forces.

p

Frequency of the dominant allele at a two-allele locus.

q

Frequency of the recessive allele at a two-allele locus.

p^2, 2pq, q^2

Expected genotype frequencies under HW equilibrium for a two-allele locus.

Natural Selection

Differential survival and reproduction of individuals due to heritable variation, shaping population traits over time.

Adaptation

A trait that increases an organism’s fitness in a given environment.

Fitness

Reproductive success; the contribution of an individual’s genes to the next generation.

Genetic Variation

Differences in DNA sequences among individuals in a population.

Mutation Rate

The frequency at which new genetic changes arise in a population (often germline).

Genetic Drift

Random changes in allele frequencies due to chance, especially in small populations.

Bottleneck

A drastic reduction in population size that alters allele frequencies and reduces genetic diversity.

Founder Effect

A new population started by a small number of individuals, leading to different allele frequencies.

Gene Flow

Movement of genes between populations via immigration or emigration.

Non-random Mating

Mating that is not random with respect to genotype or phenotype, including sexual selection.

Sexual Selection

Differential reproductive success due to variation in mating success, often causing dimorphism.

Sexual Dimorphism

Differences in traits between males and females beyond reproductive organs.

Mitosis

Cell division producing two genetically identical diploid daughter cells.

Meiosis

Cell division producing four genetically diverse haploid gametes; includes crossing over and independent assortment.

Homologous Chromosomes

Pairs of chromosomes that carry the same genes in the same order but may have different alleles.

Crossing Over

Exchange of genetic material between non-sister chromatids during Prophase I of meiosis.

Recombination

Generation of new allele combinations through crossing over and independent assortment.

Independent Assortment

Random orientation of homologous chromosome pairs during meiosis I, generating diverse gametes.

Linked Genes

Genes located close together on the same chromosome that tend to be inherited together.

Recombinant Offspring

Offspring with new combinations of alleles not found in the parents due to crossing over or independent assortment.

Pedigree

A family tree used to study inheritance patterns of traits across generations.

X-linked

Genes located on the X chromosome; inheritance shows sex-specific patterns.

Autosome

Any chromosome that is not a sex chromosome.

Sex-linked Diseases

Diseases associated with genes on the X or Y chromosomes (e.g., color blindness, hemophilia).

Phenotypic Plasticity

The ability of an organism to alter its phenotype in response to environmental conditions.

Twin Studies

Research comparing monozygotic and dizygotic twins to estimate genetic vs. environmental influences.

Population Genetics

Study of how allele frequencies in a population change over time under evolutionary forces.

Boxplot

A graphical summary of data showing median, quartiles, and extremes.

Boxplot Quartiles

Divisions of data into four equal parts; the box shows the middle 50% of data.

Null Model

A baseline assumption used to determine if an observed effect deviates from randomness, often HW in genetics.

Boxplots and Boxplots in Evolution

Boxplots summarize distributions of traits (e.g., beak size, body mass) to compare survivors vs. nonsurvivors in studies.

Biodiversity in Darwin’s Finches

Beak shape and size variation among finch species from the Galápagos as evidence of adaptive evolution.

HWE Assumptions

Large population, no mutation, random mating, isolation from other populations, no natural selection.

Phenotype vs Genotype

Phenotype is the observable traits; genotype is the genetic makeup at a locus.

Homozygous vs Heterozygous

Homozygous: two identical alleles; heterozygous: two different alleles at a locus.

Dominant vs Recessive Traits (Concept)

Dominant masks recessive in a heterozygote; recessive is expressed only in homozygous recessive.

Direct Selection (Natural Selection)

Beneficial traits increase survival and reproduction, shifting allele frequencies.

Pleiotropy

One gene influences multiple, seemingly unrelated phenotypic traits.

Epistasis

One gene’s expression depends on another gene, influencing phenotype.

Heterozygote Advantage

Heterozygous individuals have higher fitness than either homozygote, maintaining variation.

Codominance

Both alleles in a heterozygote are fully expressed (e.g., AB blood type).

Incomplete Dominance

Heterozygote phenotype is intermediate between the two homozygotes (e.g., pink flowers).

Blood Groups (ABO)

Three alleles (A, B, O) with A and B codominant and O recessive.

Genetic Linkage

Genes located close together on a chromosome tend to be inherited together.

Recombination Frequency

Proportion of recombinant offspring; used to map distance between genes on a chromosome.

Genetic Map/Map Units

Distance between genes based on recombination frequency; 1 map unit = 1% recombination.

Sex Chromosome Inheritance

Inheritance patterns governed by genes on X or Y chromosomes; often different in males and females.

Pedigree Analysis

Using family trees to infer whether a trait is dominant, recessive, or sex-linked.

Phenotypic Plasticity

The capacity of a genotype to produce different phenotypes in different environments.

Hardy-Weinberg Equilibrium (Formula)

p^2 + 2pq + q^2 = 1 and p + q = 1, describing allele/genotype frequencies under no evolution.

p and q in HW

p is the frequency of the dominant allele, q is the frequency of the recessive allele; p + q = 1.

Test Cross

Crossing an individual with a homozygous recessive to determine unknown genotype.

Karyotype

The number and visual appearance of chromosomes in a cell or organism.

Meiosis I vs Meiosis II

Meiosis I separates homologous chromosomes; Meiosis II separates sister chromatids, producing four haploid cells.

Crossing Over (Chiasmata)

Exchange of genetic material between non-sister chromatids during Prophase I.

Independent Assortment (Meiosis I)

Random orientation of homologous chromosome pairs leads to diverse gametes.

Fossil Record

Documented history of life on Earth showing gradual changes and extinctions over time.

Vestigial Structures

Remnant structures with little or no current function that hint at evolutionary history.

Homologous Structures

Similar bones in different species that serve different purposes, indicating common ancestry.

Convergent Evolution

Different lineages evolve similar features independently, not from a common ancestor.

Biogeography

Study of the geographic distribution of species and how it informs evolutionary history.

Red Queen Hypothesis

Sexual reproduction enables rapid genetic change to keep up in coevolutionary ‘arms races’ with parasites.