Biology Chapter 11: Evolution and Its Processes

The process where species characteristics change and new ones arise.

A unifying biological theory used by scientists to study living things.

A theory used by biologists to study living organisms.

A group of organisms with common characteristics which can interbreed.

The shared ancestor from which multiple species evolved.

Something that continues with no end.

Mechanisms and processes that shapes diversification of life.

Ukrainian-born American geneticist.

Before Darwin, general belief held species as unchanging, rooted in Plato's writings. However, evolutionary ideas existed in ancient Greece and were expanded upon in the 18th century.

Darwin's theory of evolution proposed a mechanism for species change over time, contrasting with the prevailing view at the time.

The Scottish naturalist, Hutton, proposed that geological changes occur gradually over long periods via ongoing processes, challenging the idea of catastrophic events.

Lyell's geological ideas influenced Darwin by arguing that Earth's age allows more time for species change, providing an analogy for gradual change in species.

Lamarck proposed inheritance of acquired characteristics. Changes due to environment or use/disuse of traits during an organism's lifetime could be inherited by offspring.

A theory proposed by Lamarck suggesting that changes in an organism during its lifetime due to the environment or use/disuse of structures, could be passed down to its offspring.

The study of how populations evolve using genetic principles (not provided in detail).

Evolutionary ideas emerged gradually from the ancient past - progressing to Hutton's emphasis on gradual change, Lyell's support, and Lamarck's specific mechanism. These concepts were precursors to Darwin's later theory.

When two species evolve in different directions from a common ancestor.

Structures that have similar functions and appearances in different species but evolved independently.

Structures that share similarities due to descent from a common ancestor, even if they have different functions.

When unrelated species evolve similar traits due to adapting to similar environments.

An outdated theory that incorrectly claimed traits mix completely during inheritance.

Analogous structures are similar because of convergent evolution (independent evolution), whereas homologous structures share similarities due to common ancestry.

It suggested that variation would be lost across generations, making it hard for natural selection to act on traits.

A deeper understanding of heredity or genetics, which was later provided by Gregor Mendel's work.

A state where allele and genotype frequencies in a population remain stable across generations, assuming no evolutionary forces are acting on the population.

Factors that disrupt the Hardy-Weinberg equilibrium causing changes in allele or genotype frequencies within a population.

The four most important evolutionary forces are: natural selection, mutation, genetic drift, and migration. A fifth factor, nonrandom mating, also disrupts the equilibrium, but only by impacting genotype frequencies, not allele frequencies unless it influences reproductive potential.

The process where organisms with traits better suited to their environment survive and reproduce more successfully, passing these traits on to their offspring. This leads to a gradual change in the population's gene pool.

A change in the DNA sequence of an organism. This change can create a new allele and thus increase or decrease its frequency in a population.

Random fluctuations in allele frequencies, especially significant in smaller populations. This can cause loss or fixation of alleles.

The movement of individuals into or out of a population, which can introduce or remove alleles, altering allele frequencies.

When individuals choose mates based on specific phenotypes rather than randomly. This affects genotype frequencies but not necessarily allele frequencies unless phenotype influences reproduction.

It provides a baseline for comparing allele frequencies in real populations, helping scientists identify and study the evolutionary forces at play.

A special form of natural selection that favors traits that enhance an individual's chances of mating and producing offspring.

Competition between members of the same sex (usually males) for access to mates.

One sex (usually females) chooses mates based on specific traits, leading to the evolution of those preferred traits.

Direct competition between males for resources, territory, or access to females, often leading to ritualized fights or dominance displays.

The evolution of traits favored through sexual selection can be constrained by natural selection if they negatively impact survival, creating a balance between mating success and survival.

The collection of preserved remains and traces of past organisms found in layers of rock, providing evidence of evolutionary change.

Fossils showing intermediate anatomy between earlier and later forms, demonstrating the evolutionary stages between species.

The rapid evolution of new species from a common ancestor into many diverse forms, often driven by environmental change.

The theory that evolutionary change occurs slowly and continuously over long periods, driven by natural selection.

The fossil record shows how species have changed over time through transitional fossils, displaying evolutionary relationships and adaptive radiations, providing evidence of the evolutionary process.