Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Types of Selection

Types of Selection

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...

Limits to Natural Selection

Limits to Natural Selection

Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.

What is Natural Selection?

What is Natural Selection?

Natural selection is an evolutionary process in which individuals with survival-promoting traits reproduce at higher rates. These favorable traits become more common within a population or species. Naturally selected traits initially arise via random genetic mutations. In order for selection to occur, there must be variation within a population, the trait controlling the variation must be heritable, and there must be an evolutionary advantage for variation in the trait.

Antibiotic Selection

Antibiotic Selection

Frequency-dependent Selection

Frequency-dependent Selection

When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.

Natural Selection and Adaptation

Natural Selection and Adaptation

Natural selection, a fundamental concept in evolutionary biology, is the mechanism by which evolution is driven, favoring organisms that are best adapted to their environments. This process enhances their chances of survival and reproduction. Adaptation, a key outcome of this process, involves genetic modifications that optimize an organism's functionality under specific environmental challenges, such as extreme cold or thinner air at high altitudes.
Beyond physical adaptations,...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

A Survey of Salmonella Contamination in Modern Broiler Production.

Journal of food protection·2019

Same author

A Survey of Campylobacter jejuni Contamination in Modern Broiler Production and Processing Systems.

Journal of food protection·2019

Same author

ASD restricted and repetitive behaviors associated at 17q21.33: genes prioritized by expression in fetal brains.

Molecular psychiatry·2017

Same author

TNF-α modulates genome-wide redistribution of ΔNp63α/TAp73 and NF-κB cREL interactive binding on TP53 and AP-1 motifs to promote an oncogenic gene program in squamous cancer.

Oncogene·2016

Same author

A mutant p53/let-7i-axis-regulated gene network drives cell migration, invasion and metastasis.

Oncogene·2014

Same author

Methodology of the 2009 Survey on Living with Chronic Diseases in Canada--hypertension component.

Chronic diseases and injuries in Canada·2013

Same journal

Encore! Encore!

Physician executive·2014

Same journal

The medical loss ratio: a core component of reform.

Physician executive·2014

Same journal

Avoid the breach: put data security measures in place.

Physician executive·2014

Same journal

Hospitals of excellence and geography: an update.

Physician executive·2014

Same journal

Collegial intervention and the disruptive physician.

Physician executive·2014

Same journal

Standardizing electronic medical record documentation.

Physician executive·2014

See all related articles

Search research articles

Related Experiment Video

Updated: Jan 26, 2026

Author Spotlight: Advancing Human Brain Modulation – Optimized Protocols for Transcranial Ultrasound Stimulation Experiments

Author Spotlight: Advancing Human Brain Modulation – Optimized Protocols for Transcranial Ultrasound Stimulation Experiments

Published on: June 28, 2024

Selecting a physician executive.

Physician Executive

|October 6, 1989

Summary

This summary is machine-generated.

Finding qualified physician executives is challenging due to high demand and limited supply. Many organizations are unfamiliar with recruiting for roles like Medical Director or Vice President of Medical Affairs.

More Related Videos

Setup and Execution Of the Blindfolded Code Training Exercise

Setup and Execution Of the Blindfolded Code Training Exercise

Published on: March 29, 2019

Using Brain Activation nir-HEG/Q-EEG and Execution Measures CPTs in a ADHD Assessment Protocol

Using Brain Activation nir-HEG/Q-EEG and Execution Measures CPTs in a ADHD Assessment Protocol

Published on: April 1, 2018

Related Experiment Videos

Last Updated: Jan 26, 2026

Author Spotlight: Advancing Human Brain Modulation – Optimized Protocols for Transcranial Ultrasound Stimulation Experiments

Author Spotlight: Advancing Human Brain Modulation – Optimized Protocols for Transcranial Ultrasound Stimulation Experiments

Published on: June 28, 2024

Setup and Execution Of the Blindfolded Code Training Exercise

Setup and Execution Of the Blindfolded Code Training Exercise

Published on: March 29, 2019

Using Brain Activation nir-HEG/Q-EEG and Execution Measures CPTs in a ADHD Assessment Protocol

Using Brain Activation nir-HEG/Q-EEG and Execution Measures CPTs in a ADHD Assessment Protocol

Published on: April 1, 2018

Area of Science:

Healthcare Management
Physician Leadership

Background:

The demand for physician executives significantly exceeds the available supply of qualified candidates.
The number of physicians in management roles has increased, but not enough to meet current needs.

Purpose of the Study:

To highlight the complexities and challenges in selecting physician executives.
To address the growing gap between the demand for and supply of physician leaders.

Main Methods:

Analysis of physician executive market trends.
Review of recruitment processes for medical leadership positions.

Main Results:

High demand for physician executives complicates the selection process.
A shortage of experienced physician executives persists despite growth in the field.

Conclusions:

Organizations face difficulties in recruiting for roles like Medical Director or VP of Medical Affairs.
The recruitment process for these specialized roles is often new to many healthcare organizations.