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

Genetic Drift

Genetic Drift

Natural selection—probably the most well-known evolutionary mechanism—increases the prevalence of traits that enhance survival and reproduction. However, evolution does not merely propagate favorable traits, nor does it always benefit populations.

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.

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.

Conservation of Declining Populations

Conservation of Declining Populations

Conservation of declining population focuses on ways of detecting, diagnosing, and halting a population decline. The approach uses methods to prevent populations from going extinct.

Light Acquisition

Light Acquisition

In order to produce glucose, plants need to capture sufficient light energy. Many modern plants have evolved leaves specialized for light acquisition. Leaves can be only millimeters in width or tens of meters wide, depending on the environment. Due to competition for sunlight, evolution has driven the evolution of increasingly larger leaves and taller plants, to avoid shading by their neighbors with contaminant elaboration of root architecture and mechanisms to transport water and nutrients.

Survival Tree

Survival Tree

Survival trees are a non-parametric method used in survival analysis to model the relationship between a set of covariates and the time until an event of interest occurs, often referred to as the "time-to-event" or "survival time." This method is particularly useful when dealing with censored data, where the event has not occurred for some individuals by the end of the study period, or when the exact time of the event is unknown.
Building a Survival Tree
Constructing a survival tree begins...

You might also read

Related Articles

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

Sort by

Same author

Divergent population trajectories despite similar response to temperature in a widespread aerial insectivore.

Proceedings of the National Academy of Sciences of the United States of America·2026

Same author

Individual trajectories of fertility with age highlight the costs of reproduction in a pre-industrial population.

Proceedings. Biological sciences·2026

Same author

No Pedigree, No Problem: Genomic Inbreeding Tracks Genetic Rescue With High Resolution.

Evolutionary applications·2026

Same author

Genome size and phenotypic change: insights on contemporary evolution across biological groups.

Journal of evolutionary biology·2026

Same author

"The landscape of love": sex-specific habitat-use during the mating season in a solitary large carnivore.

Landscape ecology·2025

Same author

Family Breakup Dynamics in a Promiscuous Solitary Mammal.

Ecology and evolution·2025

Search research articles

Related Experiment Video

Updated: May 22, 2026

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Published on: August 8, 2017

Data from selective harvests underestimate temporal trends in quantitative traits.

Fanie Pelletier¹, Marco Festa-Bianchet, Jon T Jorgenson

¹Département de Biologie, Université de Sherbrooke, 2500 boulevard de l'Université, Sherbrooke, Québec, Canada. fanie.pelletier@usherbrooke.ca

Biology Letters

|May 4, 2012

Summary

Trophy hunting can cause evolutionary changes in wild populations, like bighorn sheep horn size decline. Harvest records may underestimate these changes due to selective hunting, impacting conservation efforts.

More Related Videos

Development of an Individual-Tree Basal Area Increment Model using a Linear Mixed-Effects Approach

Development of an Individual-Tree Basal Area Increment Model using a Linear Mixed-Effects Approach

Published on: July 3, 2020

Measurement of Lifespan in Drosophila melanogaster

Measurement of Lifespan in Drosophila melanogaster

Published on: January 7, 2013

Related Experiment Videos

Last Updated: May 22, 2026

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Published on: August 8, 2017

Development of an Individual-Tree Basal Area Increment Model using a Linear Mixed-Effects Approach

Development of an Individual-Tree Basal Area Increment Model using a Linear Mixed-Effects Approach

Published on: July 3, 2020

Measurement of Lifespan in Drosophila melanogaster

Measurement of Lifespan in Drosophila melanogaster

Published on: January 7, 2013

Area of Science:

Ecology
Evolutionary Biology
Wildlife Management

Background:

Human harvesting can impose artificial selection on wild populations.
Managers often use harvest data to track population changes, but data bias is a concern.
Previous studies reported evolutionary changes in bighorn sheep due to trophy hunting.

Purpose of the Study:

To assess the ability to detect horn size decline in bighorn sheep (Ovis canadensis).
To compare trends in horn size between harvested males and all males in the population.
To evaluate the reliability of harvest records for monitoring evolutionary changes.

Main Methods:

Comparing horn size data from harvested bighorn sheep rams with data from all rams in the population.
Analyzing temporal trends in horn size over time.
Investigating the impact of hunting regulations on harvest selectivity.

Main Results:

Harvest records underestimated the temporal decline in bighorn sheep horn size.
An increasing proportion of rams were not harvested due to horns being smaller than the legal threshold.
Selective harvesting biased the temporal trends observed in harvest data.

Conclusions:

Harvest data can be biased and may underestimate the magnitude of evolutionary changes in wild populations.
Conservation and wildlife managers must account for selective harvesting when interpreting population trends.
Understanding harvest selectivity is crucial for effective natural resource management and conservation strategies.