Evolution and Systematics Test 2

Big Bang

The beginning of the known universe, approximately 14 billion years ago.

Formation of Earth

Earth formed approximately 4.5 billion years ago.

First Life on Earth

Life first appeared on Earth approximately 3.5 billion years ago.

First Eukaryotes

The first complex cells appeared approximately 2 billion years ago.

Goldilocks Zone (Habitable Zone)

The area around a star where conditions are not too hot or too cold for liquid water to exist.

Primordial Soup Model

The hypothesis that life began through a series of chemical reactions in water using an external energy source, such as lightning or ultraviolet light.

Stanley Miller and Harold Urey

Scientists who attempted to recreate the chemical conditions of primitive Earth in a laboratory during the 1960s.

Emergent Properties

New properties that appear as simpler components combine to form more complex structures.

Characteristics of Life

Life has structural organization, metabolism, responses to environmental conditions, growth and reproduction, homeostasis, and a heritable blueprint.

Structural Organization

The arrangement of living components into an organized system with an inside and an outside.

Metabolism

The control and coordination of chemical reactions within an organism.

Homeostasis

The ability to adjust internal conditions to maintain a stable equilibrium.

Heritable Blueprint

Encoded genetic information that is transmitted between generations.

Natural Selection

The process that promotes organisms with advantageous inherited traits and removes those with less favorable traits.

Protocells

Early cell-like structures that developed before modern cells.

DNA-Protein Paradox

The problem that DNA is needed to code for proteins, but proteins are needed to replicate DNA.

RNA World Hypothesis

The hypothesis that early life began with RNA molecules capable of storing genetic information and helping copy themselves.

Evolution from RNA to DNA

The use of DNA as a more stable genetic information carrier allowed larger genomes and freed RNA to specialize in other functions.

Deep Sea Vent Hypothesis

The hypothesis that life began near deep-sea hydrothermal vents, sometimes called black smokers.

Origin of Complex Life

Prokaryotic life may have evolved relatively easily, but complex life took much longer, with the first eukaryotes appearing about 2 billion years ago.

Fundamental Difference Between Prokaryotes and Eukaryotes

Eukaryotes have mitochondria and two genomes, while prokaryotes lack mitochondria and generally have one genome.

Horizontal Gene Transfer

The movement of genetic material from one cell or organism to another rather than from parent to offspring.

Vertical Gene Transfer

The transfer of genetic information from parent to offspring.

Environmental Metagenome

A pool of genes that different prokaryotic species can incorporate into their genomes.

Gene Exchange in Prokaryotes

Prokaryotes can gain or lose genes independently of reproduction through horizontal gene transfer.

Gene Exchange in Eukaryotes

Genetic changes are primarily passed between generations through reproduction, with horizontal gene transfer being rare in contemporary eukaryotes.

Prokaryotic Replication Speed

A major determinant of prokaryotic success because rapid replication helps organisms compete and spread.

Prokaryotic Complexity Limitation

According to the lecture, prokaryotes remained relatively simple for over a billion years despite becoming highly efficient at extracting energy and replicating.

Endosymbiont Hypothesis

The hypothesis that a eukaryotic cell evolved first and later captured a prokaryote that became the mitochondrion.

Chimera Hypothesis

The hypothesis that a bacterium and an archaeon fused to form a new organism, eventually producing the eukaryotic cell.

Evidence for the Endosymbiotic Origin of Mitochondria

Mitochondria resemble bacteria in size, have circular DNA without introns, and replicate through fission.

Nuclear Genome

The main genetic information center of a eukaryotic cell, containing most of its genes and controlling many cellular functions.

Mitochondrial Genome

The genetic material retained within mitochondria, containing a small set of genes important for mitochondrial energy production.

Evolution of Chloroplasts

Chloroplasts evolved from prokaryotes after mitochondria and became organelles in certain eukaryotes.

Proto-Eukaryote

A cell on its way to becoming a eukaryote but not yet fully developed.

Genomic Consolidation

The evolutionary restructuring of two original genomes into the modern nuclear and mitochondrial genomes.

Origin of Nuclear DNA

The nuclear genome originated from the archaeal partner in the lecture's chimera hypothesis.

Origin of Mitochondrial DNA

The mitochondrial genome originated from the bacterial partner in the lecture's chimera hypothesis.

Genome Reduction in Mitochondria

Mitochondria lost most of their original genes, with many genes being transferred to the nucleus.

Electron Transport System

Protein complexes in mitochondria that use energy from electrons to pump protons across a membrane.

Oxidative Phosphorylation (OXPHOS)

The process that uses the energy stored in a proton gradient to generate ATP; it produces most of the energy from cellular respiration.

Aerobic Respiration

The process of using oxygen to extract energy from food, producing carbon dioxide, water, and ATP.

Cellular Respiration

The process by which cells convert energy from food into ATP.

Glycolysis

The first phase of cellular respiration, which occurs in the cytoplasm.

Krebs Cycle

A stage of cellular respiration that occurs in the mitochondrial matrix.

Inner Mitochondrial Membrane

The membrane where the electron transport system and oxidative phosphorylation occur.

Proton Gradient

A difference in proton concentration across a membrane that stores energy used to produce ATP.

ATP

The molecule cells use to transfer and supply energy for cellular processes.

Mitonuclear Coadaptation

The coordination of functions performed by mitochondrial and nuclear gene products to achieve oxidative phosphorylation.

Mitonuclear Interactions

Interactions between proteins encoded by mitochondrial and nuclear genes that are necessary for effective energy production.

CORR Hypothesis

The co-location-for-redox-regulation hypothesis proposes that some genes remain in mitochondria to allow local control of energy production.

Introns and Mitochondrial DNA

The lecture proposes that mitochondrial DNA entering the nuclear genome contributed to the appearance of introns in early eukaryotes.

Nuclear Membrane and Introns

The lecture proposes that the nuclear membrane helped separate transcription from translation, giving RNA time to be processed before translation.

Alternative Splicing

The processing of RNA in different ways to produce different protein products from the same gene.

Mitochondrial Genome and Disease

Harmful mitochondrial gene variants can cause inherited diseases.

Mitochondrial Genes and Speciation

Differences in mitochondrial genes can play a role in the evolution of reproductive or genetic differences between populations.

Mitochondrial-Nuclear Genomic Conflict

A conflict that can occur when mitochondrial and nuclear genes have different evolutionary interests.

Levels of Selection

The different levels at which natural selection may operate, including genes, individuals, and groups.

Gene-Level Selection

The idea that individual genes promote their own spread through a population.

Selfish Gene Theory

The idea that adaptive evolution occurs through the differential survival and transmission of competing genes.

Richard Dawkins

The evolutionary biologist associated with popularizing the selfish gene theory.

Genomic Conflict

A conflict within an organism in which one or more genes promote their own transmission at the expense of other genes in the same genome.

Outlaw Genes

Genes that promote their own transmission at the expense of most other genes in the genome.

Selfish Genes versus Outlaw Genes

Selfish genes promote their own spread but do not necessarily harm other genes; outlaw genes directly harm other genes.

Green-Beard Effect

A hypothetical mechanism in which a gene causes a recognizable trait, allows individuals to recognize that trait in others, and promotes preferential treatment of those individuals.

Group Selection Theory

The idea that natural selection acts at the level of groups rather than individuals.

Problem with Group Selection

Selfish individuals can gain an advantage over cooperative individuals within a group, allowing cheating strategies to spread.

Individual Selection Theory

The idea that natural selection acts primarily at the level of individual organisms.

Unit of Natural Selection

The individual organism is the unit emphasized by individual selection theory.

Personal Fitness

The number of offspring an individual produces.

Inclusive Fitness

An individual's genetic representation in the next generation through both its own offspring and the offspring of relatives.

Indirect Fitness

The genetic contribution an individual makes through helping relatives reproduce.

Kin Selection

Natural selection involving the effects of an individual's behavior on the reproductive success of genetic relatives.

Hamilton's Rule Concept

The idea that helping relatives can be favored by selection when the genetic benefit to relatives outweighs the cost to the helper.

Maternal Inheritance of Mitochondria

The pattern in which offspring inherit mitochondria from their mother rather than from both parents.

Genetic Dead End of Male Mitochondria

When mitochondria are inherited only from females, mitochondrial genes in males are not transmitted to future generations.

Genomic Conflict in Mitochondria via males and females

A conflict arising because nuclear genes are passed on through both males and females, while maternally inherited mitochondrial genes are passed on only through females.

Mother's Curse

The accumulation of mitochondrial mutations that harm males but have little or no harmful effect on females, allowing those mutations to persist.

Mitochondrial Mutations Harmful to Males

Mutations that reduce male fitness may not be efficiently removed by natural selection when mitochondrial genes are transmitted only through females.

Recombination

The exchange of corresponding sections of chromosomes, producing new combinations of genetic information.

Two-Fold Cost of Sex

The idea that sexual reproduction can have a reproductive cost because females producing offspring asexually could potentially produce more descendants than females investing in sexual reproduction.

Other Costs of Sex

Sexual reproduction can involve mate-searching costs, sexually transmitted diseases, and the disruption of successful gene combinations.

Paradox of Sex

The problem of explaining why sexual reproduction remains widespread despite its costs compared with asexual reproduction.

Adaptable Genotype Theory of Sex

The theory that recombination creates genetic diversity that helps populations keep up with changing environments.

Red Queen Hypothesis

The idea that organisms must continually evolve to keep up with changing environments, including evolving pathogens.

Pathogen Co-Evolution

The ongoing evolutionary interaction between hosts and pathogens, proposed as a major force favoring sexual reproduction.

Problems with the Adaptable Genotype Theory

Novel gene combinations can also arise without sex, and recombination can break up successful gene combinations.

Mutational Theory of Sex

The theory that sexual reproduction is beneficial because recombination helps remove harmful mutations and allows beneficial mutations to spread independently.

Mutational Load

The genetic burden in a population caused by accumulated harmful mutations.

Mutational Erosion

The loss of fitness caused by the accumulation of deleterious alleles.

Muller's Ratchet

The irreversible accumulation of deleterious mutations in an asexual population when there is no recombination to remove them.

Selection Sweep

A process in which selection on an allele at one genetic location affects the frequency of alleles at another linked location.

Hill-Robertson Effect

The effect in which selection on one allele interferes with selection on other linked alleles, potentially allowing harmful alleles to increase in frequency.

Genetic Linkage

The tendency of alleles located close together on a chromosome to be inherited together.

Benefits of Recombination

Recombination allows natural selection to promote beneficial genes and remove harmful genes separately instead of selecting for entire linked chromosomes.

Nuclear Bombardment Hypothesis for the Evolution of Sex

The hypothesis that sex evolved partly in response to mitochondrial DNA entering and disrupting the nuclear genome early in eukaryotic evolution.

Nuclear Bombardment

The transfer of mitochondrial DNA into nuclear DNA, which the lecture proposes created a challenge for early eukaryotes.

Mating Type

A genetically determined phenotype that can produce a zygote only with a different mating type.

Anisogamy

A reproductive system in which gametes occur in distinct size classes.

Isogamy

A reproductive system in which gametes occur in one size class.