FULL SET- Exam 2 concepts

Natural selection

Process where individuals with advantageous traits survive and reproduce more.

Variation

Differences in traits among individuals in a population.

Inheritance

Passing traits from parents to offspring.

Struggle for existence

Competition for limited resources.

Adaptation

Trait that increases fitness in a given environment.

Fitness

Reproductive success of an individual.

Artificial (domestic) selection

Human-driven selection for desired traits.

Sexual selection

Selection for traits that increase mating success.

Sexual dimorphism

Physical differences between sexes of the same species.

Unequal mating success

Some individuals reproduce more than others due to traits or behaviors.

Mate choice

Selection of partners based on traits or displays.

Random mutation

Genetic change not directed by environment.

Neutral mutation

No effect on fitness.

Deleterious mutation

Harmful to fitness.

Beneficial mutation

Improves fitness.

Mutation

Change in DNA sequence.

Genetic drift

Random changes in allele frequencies.

Bottleneck event

Sharp reduction in population size → loss of genetic diversity.

Founder effect

New population established by few individuals → reduced variation.

Allopatric speciation

Formation of new species due to geographic isolation.

Geographic isolation

Physical separation of populations.

Reproductive isolation

Barriers preventing interbreeding.

Cell membrane

Boundary controlling movement of substances in/out of cell.

Nucleus

Organelle containing DNA in eukaryotes.

Organelle

Specialized structure within cells.

Mitochondrion

Organelle for aerobic respiration, produces ATP.

Chloroplast

Organelle for photosynthesis in plants/algae.

Prokaryotic

Cells lacking nucleus/membrane-bound organelles (bacteria, archaea).

Eukaryotic

Cells with nucleus and organelles.

Fission

Asexual reproduction in prokaryotes (binary fission).

Lateral transfer

Movement of genes across species (horizontal gene transfer).

Microbe

Microscopic organism.

Nitrogen fixation

Conversion of N₂ → organic nitrogen compounds (NH₄⁺, NO₂⁻, NO₃⁻).

Photosynthesis

CO₂ + H₂O → sugar + O₂.

Autotroph

Produces its own food (photosynthesis/chemosynthesis).

Heterotroph

Consumes organic molecules for energy.

Respiration

Breaking down sugars for energy (ATP).

Gram stain

Differentiates bacteria by cell wall structure (Gram+ vs Gram−).

Extremophile

Organism living in extreme environments.

Nuclear membrane

Double membrane surrounding nucleus.

Pseudopodia

Extensions of cytoplasm for movement/feeding.

Flagella

Whip-like tail for movement.

Cilia

Short hair-like projections for movement.

Bioluminescence

Light production by organisms.

Test

External shell/covering (protists).

Multicellularity

Organisms composed of multiple cells.

Alternation of generations

Life cycle with both haploid (gametophyte) and diploid (sporophyte) stages.

Sporophyte

Diploid stage producing spores.

Gametophyte

Haploid stage producing gametes.

Phytoplankton

Photosynthetic plankton (autotrophic).

Zooplankton

Animal-like plankton (heterotrophic).

Primary endosymbiosis

Eukaryote engulfed a cyanobacterium → chloroplasts.

Secondary endosymbiosis

Eukaryote engulfed another eukaryotic alga → complex plastids.

Multiple-walled membranes

Evidence for secondary endosymbiosis (extra membranes around plastids).

Plastid

General term for chloroplast and related organelles.

Chlorophyll

Pigment absorbing light for photosynthesis.

Prokaryotes

Unicellular organisms without nucleus (Bacteria + Archaea).

Bacteria

Prokaryotes with peptidoglycan cell walls.

Archaea

Prokaryotes often extremophiles; unique membranes.

Eukarya

Domain of organisms with nucleus + organelles.

Firmicutes

Gram-positive bacteria (e.g., Streptococcus).

Actinobacteria

Gram-positive, soil bacteria, many produce antibiotics (Streptomyces).

Proteobacteria

Large diverse group, includes E. coli.

Rickettsiales

Intracellular bacteria, ancestor to mitochondria.

Cyanobacteria

Photosynthetic prokaryotes, important for O₂ production.

Protista

Diverse eukaryotes not in plants/animals/fungi.

Dinoflagellates

Protists, some cause red tide, many are bioluminescent.

Diatoms

Photosynthetic algae with silica shells.

Brown algae

Multicellular, photosynthetic, include kelps.

Amoebozoa

Protists with pseudopodia.

Streptococcus

Firmicute; causes strep throat.

Lactobacillus

Firmicute; lactic acid bacteria used in yogurt.

Streptomyces

Actinobacteria; produce antibiotics.

Escherichia coli (E. coli)

Proteobacteria; gut bacteria, lab model.

Thermus aquaticus

Source of Taq polymerase for PCR.

Artificial selection

Human-driven selection of traits.

Prokaryote

No nucleus/organelles.

Eukaryote

Nucleus + organelles.

Endosymbiosis

Eukaryotes gained mitochondria & chloroplasts via engulfing bacteria.