Related Experiment Video
Updated: Mar 19, 2026

04:57
Proper Care and Cleaning of the Microscope
Published on: August 11, 2008
45.9K
Strengthening JOSA A-our new topical editors in action: editorial
Abstract
None:
Editor-in-Chief Olga Korotkova summarizes the Journal's progress in 2025, recognizes editors who have completed their terms, and introduces editors who have recently joined the board.
Related Concept Videos
Proofreading
61.9K
Overview
61.9K
Proofreading
9.7K
Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore, it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase...
Errors During Replication are Corrected by the DNA Polymerase...
9.7K
Types of Selection
46.1K
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
46.1K
Ecological Niches
27.2K
All organisms have a position within an ecosystem. The complete set of living and nonliving factors—including food resources, climate, and terrain—that define the position of a given organism are collectively referred to as the organism’s ecological niche.
27.2K
Feedback Loops
67.3K
In most cases, excessive hormone production is prevented by negative feedback—a loop that starts with a stimulus inducing the release of a particular substance, like a hormone, to maintain a certain level before triggering a signal that results in a decrease in further release of the hormone.
67.3K
Competition
25.3K
When organisms require the same limited resources within an environment, they may have to compete for them. Competition is a net-negative interaction. Even if two competing individuals or populations do not interact directly, the overall fitness of both competitors is lowered as a result of not having full access to the limited resource.
25.3K

