Question

The evolution of one species into two or more species is called a gradualism. b punctuated equilibrium. c cladogenesis. d horizontal gene transfer. e microevolution.

Short answer

The correct answer is c) cladogenesis.

Step-by-step solution

Understand the Question

The question wants us to identify the term used to describe the evolutionary process where one species becomes two or more species.

Evaluate the Options

Gradualism is the concept that species evolve slowly over time. Punctuated equilibrium describes periods of apparent stasis punctuated by sudden change observed in the fossil record. Cladogenesis is the formation of a new group of organisms or species by evolutionary divergence from an ancestral form. Horizontal gene transfer is the transfer of genes between unrelated species. Microevolution describes the small-scale changes in gene frequencies in a population over a few generations.

Choose the Correct Answer

From the definitions provided, it's clear that cladogenesis is the evolutionary process where one species splits into two or more species. The other terms describe different processes or aspects of evolution.

Key concepts

Evolutionary Biology

Evolutionary biology is a branch of biological sciences concerned with the study of evolutionary processes. It provides insight into how different species originated and how they are related through a common ancestry.
This field encompasses a wide array of topics, such as genetic variation, natural selection, and the adaptation of organisms to their environments. By understanding these phenomena, scientists can unravel the complexities of life's diversity and the intricate histories of living forms.
Evolutionary biology not only explores historical developments but also contemporary changes in populations, emphasizing the dynamic nature of life on Earth.

Speciation

Speciation is the process through which new distinct species arise from a single ancestral species. This diversification can occur because of various mechanisms such as geographical isolation or genetic divergence.
In essence, speciation is like the family tree of life growing new branches. When populations of one species become isolated, either physically or genetically, they can evolve independently. This can ultimately lead to the emergence of new species.
Some important types of speciation include:

• Allopatric speciation: Occurs due to geographical barriers that separate populations.
• Sympatric speciation: Happens within a single habitat, often through genetic factors like polyploidy in plants.

Evolutionary Processes

Evolutionary processes are the mechanisms through which species evolve over time. They encompass a broad range of biological changes and adaptations that contribute to the diversity of life.
Some of the key evolutionary processes include:

• Natural Selection: The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
• Genetic Drift: Random changes in the frequency of alleles in a population.
• Mutation: Changes in the genetic material that can introduce new traits to a population.
• Gene Flow: The transfer of genetic variation from one population to another.

These processes together drive the evolution and speciation of organisms, highlighting the complexity of life's tapestry.

Gradualism

Gradualism is a theory of evolution that suggests species change slowly and continuously over time. It contrasts with the idea that significant changes occur quickly and sporadically.
According to gradualism, evolutionary changes occur in small, incremental steps rather than through large mutations or abrupt shifts. This idea is rooted in the observation of the fossil record, which often shows slight differences between successive layers.
Such a perspective aligns with Charles Darwin's view of evolution as a slow and steady process, where the cumulative effect of small variations results in significant evolutionary transformations.

Punctuated Equilibrium

Punctuated equilibrium is a model of evolution which proposes that most species will exhibit little net evolutionary change for most of their geologic history. Instead, significant changes happen relatively quickly and in rapid bursts.
This theory contrasts with gradualism by suggesting that long periods of evolutionary stasis are interrupted by short, intense periods of change that result in new species.
This model finds support in the fossil record, which often shows sudden emergence of new species, coinciding with abrupt environmental shifts or other factors that induce rapid evolutionary change. By explaining both gradual and abrupt changes, punctuated equilibrium offers a comprehensive perspective on how species may evolve.