Video Lecture Review: Evolution, Population Genetics, Phylogenetics, and Plant Biology

Vocabulary flashcards covering key terms from genetics, evolution, phylogenetics, and plant biology topics described in the notes.

Genetic variation

Differences in alleles and morphological traits among individuals in a population.

Evolution

Change in the genetic composition of a population over time.

Electrophoresis

Technique used to separate proteins or enzymes to detect variation among individuals or populations.

Restriction fragment length polymorphisms (RFLPs)

Differences in DNA fragment lengths that serve as markers for genetic variation.

Descent with modification

Darwin’s idea that species accumulate differences over time as they evolve.

Population genetics

Study of genetic variation within populations and how allele frequencies change over time.

Gene sequencing

Determining the nucleotide sequence of specific genes to study variation.

Genome sequencing

Determining the entire DNA sequence of an organism.

Natural selection

Process where individuals with advantageous traits survive and reproduce more successfully.

Single Nucleotide Polymorphisms (SNPs)

Single base-pair differences between individuals that create new alleles.

Mutation

Random change in a DNA sequence that introduces new genetic variation.

Gene flow (migration)

Movement of alleles between populations, introducing new genetic material.

Genetic drift

Random fluctuation of allele frequencies, especially in small populations.

Allele frequency

Proportion of a specific allele among all alleles for a gene in a population.

Phenotypic variation

Observable differences among individuals, often reflecting genetic differences.

Lamarckism (inheritance of acquired characteristics)

Idea that acquired traits can be inherited; rejected by modern genetics.

Blending inheritance

Old concept that offspring traits are intermediate averages of parental traits.

Natural-selection requirements

Variation exists, traits are heritable, and differential survival/reproduction occur.

Fitness

Reproductive success of a phenotype or genotype in a given environment.

Directional selection

Favors one extreme of a trait distribution, shifting the mean.

Stabilizing selection

Favors intermediate phenotypes, reducing variation.

Disruptive selection

Favors extremes over intermediates, potentially leading to speciation.

Heterozygote advantage (overdominance)

Heterozygotes have higher fitness than either homozygote (e.g., sickle cell trait and malaria).

Frequency-dependent selection

Fitness depends on how common a phenotype is in the population.

Oscillating selection

Selection that favors different phenotypes at different times or conditions.

Positive frequency-dependent selection

Common phenotypes are favored, increasing their frequency.

Negative frequency-dependent selection

Rare phenotypes are favored, maintaining variation.

Genetic drift versus population size

Drift is random allele change; effects are stronger in small populations.

Founder effect

Genetic drift when a new population is started by a few individuals.

Bottleneck effect

Sharp reduction in population size causing loss of genetic variation.

Allopatric speciation

Speciation driven by geographic isolation.

Sympatric speciation

Speciation occurring in the same geographic area without barriers.

Reinforcement

Process that strengthens reproductive isolation to prevent costly hybrids.

Prezygotic isolating mechanisms

Barriers that prevent mating or fertilization (ecological, behavioral, temporal, mechanical, gametic).

Postzygotic isolating mechanisms

Barriers after fertilization (hybrid inviability or sterility).

Homologous structures

Similar structures in different species due to shared ancestry.

Vestigial structures

Remnants of features that had function in ancestors but are reduced now.

Biogeography

Study of the geographic distribution of species and populations.

Phylogeny

The evolutionary history and relationships among species.

Cladistics

Method of inferring evolutionary relationships using shared derived characters.

Cladogram

Diagram showing relationships among organisms based on branching patterns.

Monophyletic

A group that includes a common ancestor and all its descendants.

Paraphyletic

A group that includes a common ancestor and some, but not all, descendants.

Polyphyletic

A group that does not include the most recent common ancestor of all members.

Plesiomorphy

An ancestral trait shared by multiple taxa.

Apomorphy

A derived trait that evolved in a lineage.

Synapomorphy

A shared derived trait that links a clade to a common ancestor.

Homoplasy

Similar traits that arose independently (convergent evolution) rather than from a common ancestor.

Phylogenetic species concept

Species defined by monophyletic groups with unique ancestry; sometimes controversial.

Gig and taxon terms: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Hierarchical levels of biological classification.

Gymnosperm

Seed plant with naked seeds not enclosed in fruit; usually wind-pollinated.

Angiosperm

Flowering plant that produces seeds within fruit; typically has double fertilization.

Double fertilization

In angiosperms, one sperm fertilizes the egg and a second fuses with polar nuclei to form endosperm.

Megasporangium

structure that produces megaspores in seed plants (female gymnosperms/angiosperms).

Megaspore

Haploid spore that develops into the female gametophyte.

Micropyle

Opening in the integuments of ovules through which pollen tubes enter.

Ovary

Swollen base of a carpel that contains ovules and develops into fruit.

Ovary, stigma, style, carbels terms

Key parts of the female reproductive structure in flowers: ovary (contains ovules), style (connects stigma to ovary), stigma (receives pollen).

Pollen tube

Tube that grows from pollen grain to deliver sperm to ovule.

Seed

Embryo with stored nutrients, enclosed in a protective coat.

Endosperm

Nutritional tissue formed after double fertilization in many angiosperms.

Seed dormancy

Condition in which seeds remain inactive until environmental conditions are favorable.

Seed coat

Outer protective layer of a seed.

Fruits develop from the ovary

Ovary develops into fruit enclosing seeds.

Phloem

Vascular tissue that transports sugars and nutrients through the plant.

Xylem

Vascular tissue that transports water and minerals from roots upward.

Dermal tissue

Outer protective tissue system of the plant.

Ground tissue

Tissue system for storage, photosynthesis, and support.

Vascular tissue

Tissue system that conducts water, minerals, and nutrients (xylem and phloem).

Epidermis

Outer protective layer of cells covering leaves, stems, and roots.

Cuticle

Waxy layer secreted by epidermis reducing water loss.

Guard cells

Pairs of cells that regulate stomatal opening for gas exchange.

Stomata

Pores surrounded by guard cells that control gas exchange.

Trichome

Hair-like epidermal outgrowths; can deter herbivores or secrete substances.

Root hair

Tubular extension of epidermal cell increasing surface area for absorption.

Parenchyma

Most common ground tissue; involved in storage, photosynthesis, and healing.

Collenchyma

Flexible support tissue with unevenly thickened cell walls.

Sclerenchyma

Rigid, thick-walled supportive tissue; often dead at maturity and lignified.

Apex/apical meristem

Growth region at tips of roots and shoots responsible for primary growth.

Cambium

Lateral meristem producing secondary xylem and phloem for secondary growth.

Procambium

Primary meristem giving rise to vascular tissue.

Protoderm

Primary meristem that develops into the epidermis (dermal tissue).

Ground meristem

Primary meristem giving rise to ground tissue.

Meristem

Region of actively dividing plant cells from which growth originates.

Sporophyte

Diploid phase that produces spores by meiosis in alternation of generations.

Gametophyte

Haploid phase that produces gametes by mitosis in alternation of generations.

Spore

Haploid reproductive cell that can develop into a new organism without fertilization.

Gametangium

Organ producing gametes in plants and algae.