Natural Selection

Definition

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring. It operates on the principle that individuals with favorable traits are more likely to thrive and reproduce, leading to the gradual evolution of species over time. This concept is fundamental in understanding how species adapt, evolve, and interact within ecological systems and processes.

5 Must Know Facts For Your Next Test

1. Natural selection was first articulated by Charles Darwin in the 19th century and is often referred to as 'survival of the fittest.'
2. The process relies on variation within a population, meaning not all individuals are identical, which is crucial for natural selection to occur.
3. Environmental pressures such as climate, food availability, and predators influence which traits are advantageous for survival.
4. Natural selection can lead to speciation, where new species arise from a common ancestor due to accumulated adaptations over time.
5. The concept of natural selection helps explain biodiversity, as different environments favor different traits, leading to a variety of life forms.

Review Questions

• How does natural selection contribute to the adaptation of species in their environments?
  • Natural selection contributes to adaptation by favoring individuals with traits that enhance their survival and reproductive success in a given environment. Over time, these advantageous traits become more common in the population, leading to a gradual shift in characteristics. This process enables species to become better suited to their ecological niches, promoting resilience and survival amid changing environmental conditions.
• Evaluate the role of genetic variation in the process of natural selection and how it affects populations over time.
  • Genetic variation is crucial for natural selection as it provides the raw material for evolutionary change. Without variation, all individuals would be identical, limiting adaptability and survival. The presence of diverse traits means that when environmental pressures arise, some individuals will possess characteristics that allow them to thrive while others may not. Over generations, this leads to shifts in population traits as those with beneficial adaptations are selected for, shaping the evolutionary trajectory of the species.
• Synthesize how natural selection interacts with ecological processes to shape ecosystems and biodiversity.
  • Natural selection interacts with ecological processes by influencing species interactions such as predation, competition, and symbiosis. As certain traits become advantageous through natural selection, they can alter community dynamics and ecosystem functions. For example, a predator evolving improved hunting skills may lead prey species to develop better camouflage or escape strategies. This ongoing interplay between natural selection and ecological processes drives biodiversity, as varied adaptations result in a wide range of species that occupy different roles within ecosystems.

Related terms

Adaptation:

A characteristic that improves an organism's ability to survive and reproduce in its environment.

Fitness: A measure of an organism's ability to survive and reproduce in a particular environment compared to other individuals.

Mutation: A change in the DNA sequence of an organism that can lead to new traits and variations within a population.