Evolutionary Biology and Phylogeny Quiz

Groups of organisms sharing an immediate common ancestor, each other's closest relatives.

Phylogenetic tree including the most recent common ancestor of all taxa.

Lineage diverging early in a group's history, branching near the common ancestor.

Branch point on a phylogenetic tree from which more than two groups emerge, due to limited understanding of relationships.

Phenotypic and genetic similarities due to shared ancestry.

Show patterns of descent, not phenotypic similarity. Branching order reflects descent, not age.

Phylogenies can reveal closely related species with beneficial traits for genetic transfer to cultivated plants or identify illegally harvested species.

Differences in form between closely related species, possibly due to few genetic differences or different environmental pressures.

In some trees, branch lengths represent rates of change or time, while in others, they don't hold any specific meaning.

Phylogenetic trees show evolutionary relationships, but their branching order only tells us which events came earlier or later, not the precise timing.

The principle of selecting the simplest explanation that fits observed data when reconstructing evolutionary relationships.

Characteristics that were present in an ancestor and then changed in its descendants, being a unifying feature when comparing phylogenies.

Comparing base changes in DNA sequences (e.g., A, T, G, C) helps to determine relationships among groups.

As data (e.g. DNA sequences) increases, the possible tree shapes multiply exponentially, making accurate analysis challenging.

All lineages, despite the long stretches of time, have a common ancestor.

Fossils and DNA information combine to understand the history of life on Earth.

Genes found in different species which diverged after speciation, though they may have similar functions.

Genes within the same species that diverged after gene duplication, potentially carrying out distinct tasks.

A method to estimate evolutionary time based on the rate of genetic change in orthologous genes.

The rate at which genes and genomes change over time, important for understanding evolutionary relationships.

The time elapsed since two species shared a common ancestor, revealed through molecular comparisons.

High percentage similarity between orthologous genes in different species indicates a shared evolutionary history and ancestry, reflecting conserved roles.

A substantial proportion of human genes have orthologs in yeast, demonstrating the fundamental conservation of biological processes across vastly different life forms.

A process where a section of DNA is copied, leading to an extra copy of a gene which then can evolve different functions.

The idea that many genetic changes are neutral and have little or no impact on fitness, leading to a clock-like rate of change.

Random changes in the frequency of genes in a population, affecting the molecular clock.

The assumption that most changes used in the molecular clock are not influenced by natural selection.

The speed at which genetic differences accumulate in a gene, influencing the molecular clock.

Natural selection favoring a specific trait, potentially affecting the accuracy of the molecular clock.

The impact of a gene's function on survival determines its rate of change, affecting the molecular clock.

Over long evolutionary periods, fluctuations in the rate of genetic change due to natural selection tend to even out.

Biologists are wary of conclusions derived from molecular clocks for time spans beyond fossil record calibration, as these clocks assume consistent rates over vast periods, introducing uncertainty.

Using a multitude of genes to construct molecular clocks can minimize the impact of variable evolutionary rates, leading to more accurate estimates of divergence times.

Molecular clock analysis suggests that the most common HIV strain, HIV-1 M, likely infected humans in the 1930s, based on viral samples collected over time.

The three domains—Bacteria, Archaea, and Eukarya—represent a higher taxonomic level than kingdoms, encompassing all life forms. This system recognizes the deep evolutionary split between prokaryotes.

Historically, organisms were classified into two kingdoms: plants and animals. Later, a five-kingdom system emerged, adding Monera (prokaryotes), Protista, Fungi, and Animalia.

Genetic analyses revealed that some prokaryotes differ as much from each other as they do from eukaryotes, prompting a reevaluation of the five-kingdom system.

Analyses of numerous fully sequenced genomes provide strong evidence for the validity of the three-domain system, supporting the profound separation between Bacteria, Archaea, and Eukarya.

Our understanding of the tree of life is constantly being updated as new data emerges, leading to modified classifications and a deeper appreciation for the relationships among all living things.

The three primary branches of life on Earth: Bacteria, Archaea, and Eukarya. Each domain possesses unique cellular structures, biochemical processes, and evolutionary histories.

Organisms lacking a true nucleus and membrane-bound organelles. Bacteria and Archaea are prokaryotes.

Organisms with cells containing a true nucleus and membrane-bound organelles. Plants, animals, fungi, and protists are all eukaryotes.

The transfer of genetic material between organisms that are not direct ancestors or descendants. This process can occur through mechanisms like transposable elements, plasmid exchange, and viral infection.

A diagram that depicts the evolutionary relationships between all living organisms. The branching pattern represents the evolutionary history and common ancestry of different species.

Genes that code for ribosomal RNA, a crucial component of ribosomes involved in protein synthesis. rRNA genes are used extensively in phylogenetic analysis.

Phylogenetic studies based on rRNA genes, as well as other genetic analyses, suggest that Eukarya and Archaea are more closely related to each other than either is to Bacteria.

During the early stages of life, horizontal gene transfer was prevalent, leading to significant exchange of genetic material between different domains. This resulted in a more complex and dynamic evolutionary landscape.