Evolution and Natural Selection Quiz

The pattern of change in organisms over long periods on Earth.

The process of changing allele frequencies within a population over generations.

Ancient Greek philosophers believed life originated in the sea and evolved towards more complex forms.

The idea that Earth's processes are constant over time, meaning ancient processes shaped the planet as they do today.

The incorrect belief that traits acquired during an organism's lifetime are passed on to offspring.

Charles Darwin and Alfred Russel Wallace observed that species can diversify in isolation, leading to unique adaptations.

The concept that all living organisms share a common ancestor in the distant past.

A diagram depicting the evolutionary relationships between species, using branches to show lineages and common ancestors.

A characteristic that increases an organism's chance of survival and reproduction in its environment.

The process by which organisms better adapted to their environment tend to survive and reproduce more successfully.

The ability of an organism to survive and reproduce, measured by the number of offspring it leaves behind.

A change in the nucleotide sequence of DNA.

A single base change in DNA.

A type of mutation that affects more than one base pair.

Genes that can move around and insert themselves into other parts of the genome.

The process by which populations of organisms change over time.

Different species concepts categorize organisms based on factors like reproductive isolation, morphology, genetic differences, and ecological niches. They agree that species are groups of interbreeding populations that are reproductively isolated from other such groups.

Speciation occurs when populations become reproductively isolated and evolve independently, leading to the formation of new species. This isolation can happen through geographical barriers or through changes in ecological interactions.

Pre-zygotic barriers prevent fertilization from even occurring, such as habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation. Post-zygotic barriers occur after fertilization and often result in hybrid inviability or sterility, like reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown.

Allopatric speciation occurs when populations are geographically separated, leading to independent evolution and eventually, reproductive isolation. Sympatric speciation happens when populations become reproductively isolated within the same geographical area, often due to ecological specialization or disruptive selection.

Long-term genetic separation can lead to genetic incompatibilities because populations evolve along different paths, accumulating different mutations and gene combinations. This can result in hybrid offspring that are less fit or even infertile.

Hybrids can be at a disadvantage due to reduced fitness, such as reduced viability (survival), fertility (ability to reproduce), or breakdown (poor adaptability), leading to lower chances of survival and passing on genes.

Polyploidy, the duplication of the entire set of chromosomes, can lead to instant speciation because it creates a reproductively isolated lineage. Autopolyploidy involves duplication within the same species, while allopolyploidy involves duplication from different species.

Sexual selection is a type of natural selection that favors traits that increase an organism's ability to find mates, such as bright colors, elaborate displays, or competitive behaviors.

The effective population size is the number of individuals in a population that contribute to the next generation. It is often smaller than the census population size due to factors such as unequal reproductive success, non-random mating, and genetic drift.

Heterozygosity is the proportion of individuals in a population that are heterozygous for a particular gene. It reflects the genetic diversity of a population. A lower heterozygosity indicates a smaller effective population size.

Quantitative traits are traits that are influenced by multiple genes and the environment. These traits often have a continuous distribution, unlike discrete traits which are typically controlled by one or a few genes.

The number of loci influencing a quantitative trait affects the distribution of the trait in a population. More loci lead to a wider and smoother distribution. It also affects the magnitude of allele frequency changes on genotype and phenotype frequencies.

Directional selection favors individuals with extreme phenotypes at one end of the distribution. Stabilizing selection favors individuals with the average phenotype. Disruptive selection favors individuals with extreme phenotypes at both ends of the distribution.

Directional selection increases the mean and decreases the variance of a trait. Stabilizing selection reduces the variance but doesn't affect the mean much. Disruptive selection increases the variance and can lead to bimodal distributions.

A cline is a gradual change in the frequency of an allele or trait across a geographic region. It often reflects adaptation to local conditions.

Bergmann's rule is a pattern in which organisms in colder climates tend to be larger than those in warmer climates. This is thought to be an adaptation to conserve heat.

The average number of offspring produced by an individual of age x in a population.

The average number of offspring produced by an individual of age x in a population.

The net reproductive rate of a population, measured by the total number of offspring produced per individual over their lifetime. It considers both survival and reproduction rates.

This concept explains that it can be more advantageous for an organism to delay reproduction and invest in survival and future reproduction, resulting in higher lifetime reproductive success. This is because organisms may have a higher chance of surviving to reproduce in later years, and their offspring may have a better chance of survival in a stable adult population.

Kin selection, also known as inclusive fitness, occurs when an individual's fitness is influenced by the fitness of their relatives, and not just their own survival and reproduction. It suggests that altruistic behaviors can evolve if the benefits to the relatives of the altruistic act outweigh the costs for the altruist themselves.

Hamilton's Rule formalizes the concept of kin selection. It states that altruism is favoured by natural selection if the benefit to the recipient (b) multiplied by the degree of relatedness (r) is greater than the cost to the altruist (c). In other words, the benefit to relatives needs to outweigh the cost to the individual.

A situation where an individual's fitness is influenced by the fitness of other individuals in the group, not just their own relatives. Group selection occurs when a group of individuals with certain traits is more likely to survive and reproduce than other groups, thus driving the evolution of those traits within the group.

In a haplodiploid system, females develop from fertilized eggs (diploid) and males develop from unfertilized eggs (haploid). As a result, sisters have a higher degree of relatedness (r = 3/4) than they do with their mother (r = 1/2). This can explain the evolution of eusociality in species like ants and bees, where workers can be more closely related to their sisters than their own daughters, making it more advantageous to help raise their sisters than to reproduce themselves.

Incomplete lineage sorting refers to the phenomenon where ancestral alleles persist within a population longer than expected, leading to different species inheriting different ancestral versions of the same gene. This can create misleading phylogenetic relationships, as it might appear that two species are more closely related than they truly are.

A molecular clock is a technique used to estimate the time of divergence between species based on the rate of mutations in a specific DNA sequence. Assuming a constant mutation rate, we can calculate the time elapsed by observing the number of accumulated mutations. This method has limitations as mutation rates can vary between lineages and genes.

Allometry is the study of how the size and shape of different body parts change relative to each other during growth or evolution. It describes the scaling relationships between body parts, often following a power law (y = bxa, where 'y' is the size of one body part, 'x' is the size of another body part, 'a' is the scaling exponent, and 'b' is a constant).

Heterochrony is a change in the timing of developmental events during evolution. It can lead to differences in the relative sizes or proportions of different body parts between species. Two main types include: Paedomorphosis, where adult features resemble juvenile ancestral forms, and Peramorphosis, where development is prolonged beyond the ancestral state.

Heterotopy is a change in the spatial location of a developmental process during evolution. It results in alterations to the position or structure of body parts. It reflects shifts in where certain genes are expressed, leading to evolutionary modifications.

Epigenetic effects are heritable changes in gene expression that are not caused by alterations in DNA sequence. They can be influenced by environmental factors and can affect an individual's traits. These effects do not change the DNA itself, but rather involve modifications to the DNA's packaging or the regulation of gene expression.

Homeotic mutations are alterations in the Hox genes, master control genes that determine the body plan of organisms. These mutations can result in dramatic changes in the body structure, such as the appearance of limbs in unexpected locations.

Co-option is a process in evolution where an existing gene or structure acquires a new function. It can involve repurposing a gene or structure for a completely different purpose, which can lead to surprising evolutionary adaptations.