Q4: Evolution

Evolution

The development of new types of living organisms from pre-existing types over long periods of time through cumulative changes in heritable characteristics of a population.

Gene Pool

The total collection of genes and their variants in a population, representing the genetic diversity available for evolution through processes like natural selection.

Allele Frequency

The proportion of a particular allele among all allele copies in a population.

Catastrophism

The theory that animals were annihilated by natural disasters, leading to a repopulation by other species, as proposed by Georges Cuvier.

Lamarckism

The theory of evolution that suggests organisms have an inner drive for improvement and that characteristics acquired during an organism's life are passed to offspring.

Natural Selection

A process in evolution whereby organisms better adapted to their environment tend to survive and produce more offspring.

Variation

Differences in physical traits among individuals of a population, often due to genetic differences.

Overproduction

The concept that most organisms produce more offspring than can survive to adulthood, leading to competition for resources.

Struggle for existence

The competition between organisms for limited resources such as food, space, and mates necessary for survival and reproduction.

Gradual Change

The theory that evolution occurs slowly and steadily over long periods of time, as opposed to in rapid bursts.

Mutation

A permanent alteration in the DNA sequence that makes up a gene, which can lead to changes in protein function and potentially affect an organism's traits.

Gene Mutations

Permanent alterations in the DNA sequence that make up a gene, which can lead to changes in protein function and potentially affect an organism's traits.

Chromosome Mutations

Alterations in the structure or number of chromosomes, which can include deletions, duplications, inversions, and translocations affecting genetic information.

Genome Mutations

Permanent changes in the DNA sequence of an organism's genome, which can lead to variations in traits and influence evolution.

Modification

The process of changing or altering something, often to improve its suitability for a particular purpose.

Recombination

A critical process during meiosis, specifically in prophase I, where homologous chromosomes pair and exchange segments of genetic material through a mechanism known as crossing over. This occurs when chromatids of homologous chromosomes align closely together and form structures called chiasmata, allowing for the exchange of genetic information. As a result, offspring inherit a mix of traits from both parents, increasing genetic diversity.

Genetic Drift

Random changes in allele frequencies in a population, particularly impacting smaller populations.

Bottleneck effect

A sharp reduction in the size of a population due to environmental events (such as earthquakes, floods) or human activities (like habitat destruction), leading to a loss of genetic diversity.

Founder Effect

The reduced genetic diversity that occurs when a small group of individuals establishes a new population, leading to a limited representation of the original population's genetic variation.

Speciation

The formation of new and distinct species in the course of evolution, often as a result of reproductive isolation.

Homologous Structures

Anatomical features in different species that share a common ancestry, despite differences in function.

Vestigial Structures

Body parts that have lost their original function through evolution, such as human wisdom teeth and pelvic bones.

Balanced Polymorphism

A situation where multiple phenotypic variants are maintained within a population due to selective advantages in differing environmental contexts.

Transitional Forms

Fossils or organisms that show traits common to both an ancestral form and its derived descendant group.

Adaptive Radiation

The diversification of a group of organisms into forms filling different ecological niches.

Allele Frequency

The proportion of a particular allele among all allele copies in a population.

Hardy-Weinberg Principle - calculate frequencies in populations

1. No disadvantages in selection for certain genotypes

2. No mutations

3. No preference of a particular genotypes in reproduction

4. No random effects

Isolation

The process that separates populations leading to reduced gene flow and potential speciation, often caused by geographical barriers, temporal differences, or other reproductive barriers.

Geographical Isolation

A form of isolation that occurs when a physical barrier prevents two populations from interbreeding; leads to allopatric speciation.

Temporal Isolation

A reproductive barrier where two groups breed at different times, preventing interbreeding.

Reproductive Isolation

The mechanisms that prevent two different species from interbreeding, maintaining distinct species by preventing gene flow.

Mechanical Isolation

Not compatible sexual organs

Behavioral Isolation

Incompatible mating behaviors (mating ritual)

Biotic Factors

Living factors that can influence a population such as predation and competition.

Abiotic Factors

Non-living environmental factors that can affect a population, like temperature, water supply, and soil nutrient levels.

Selection

The process by which certain traits increase in frequency within a population due to their advantageous effects on survival and reproduction.

Directional Selection

A mode of natural selection where one extreme of a trait distribution is favored, leading to a shift in the population's trait distribution.

Stabilizing Selection

A type of natural selection that favors average phenotypes, reducing variation within a population.

Disruptive Selection

A form of selection that favors extreme phenotypes over the average phenotype, potentially leading to speciation.

Artificial Selection

The process by which humans intentionally select specific traits in organisms for breeding purposes, leading to changes in those traits over generations.

Sexual Selection

A mode of natural selection where individuals with certain inherited characteristics are more likely than others to obtain mates.

Fossil Record

Chronological collection of life's remains in sedimentary rock layers, providing evidence for evolution.

Molecular Biology

The branch of biology that studies the composition, structure, and interactions of cellular molecules such as DNA, RNA, and proteins involved in the maintenance and expression of genes.

Synthetic Evidence

A concept that combines traditional evolutionary theory with modern genetics and molecular biology to explain how organisms evolve through genetic modifications and advancements in technology.