Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Convergent Evolution01:54

Convergent Evolution

Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.The structures that arise from convergent evolution are called analogous structures. They are similar in function even if they are dissimilar in structure. Further, structures can be analogous while also...
Limits to Natural Selection01:38

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.For one, natural selection can only act upon existing genetic variation. Hypothetically, redtusks may enhance elephant survival by deterring ivory-seeking poachers. However, if there are no gene variants—or alleles—for redtusks, natural selection cannot increase the prevalence of...
The Fossil Record02:56

The Fossil Record

The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
The Evidence for Evolution02:55

The Evidence for Evolution

Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.The collection of fossils within sedimentary rocks give a record of common ancestry and often depicts the history of evolution.
What is Evolutionary History?02:35

What is Evolutionary History?

Scientists record evolutionary history by analyzing fossil, morphological, and genetic data. The fossil record documents the history of life on Earth and provides evidence for evolution. However, both fossil and living organisms offer evidence that outlines Earth’s evolutionary history.Phylogenetic trees illustrate the evolutionary relationships among these organisms. Scientists infer organisms’ common ancestry by evaluating shared morphological and genetic characteristics. Together, the fossil...
Speciation Rates01:07

Speciation Rates

Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.

You might also read

Related Articles

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

Sort by
Same author

Hatchlings of <i>Tyrannosaurus rex</i> and the Evolution of Dinosaur Reproductive Strategies.

Biology·2026
Same author

The evolution of the eufalconimorph syrinx informed by phylogenetic comparative methods and diceCT imaging of falconiforms, parrots, and passerines.

Zoological journal of the Linnean Society·2026
Same author

Paleotribological models using preserved fossil tissue properties reveal functional significance of Eurasian mammoth dental evolution.

Acta biomaterialia·2026
Same author

Arctic ecosystems shaped mammalian dispersal and diversification before the Cretaceous-Paleogene mass extinction.

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

<i>Bicharracosaurus dionidei,</i> gen. et sp. nov., a new macronarian (Dinosauria, Sauropoda) from the Late Jurassic Cañadón Calcáreo Formation of Argentina and the problematic early evolution of macronarians.

PeerJ·2026
Same author

Neuroanatomical convergence between pterosaurs and non-avian paravians in the evolution of flight.

Current biology : CB·2025

Related Experiment Video

Updated: Jul 11, 2026

Creating Avian Forebrain Chimeras to Assess Facial Development
04:10

Creating Avian Forebrain Chimeras to Assess Facial Development

Published on: February 18, 2021

A basal dromaeosaurid and size evolution preceding avian flight.

Alan H Turner1, Diego Pol, Julia A Clarke

  • 1Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA. turner@amnh.org

Science (New York, N.Y.)
|September 8, 2007
PubMed
Summary

Extreme miniaturization was ancestral for early bird relatives (Paraves), challenging previous ideas about the unidirectional evolution of flight. Dinosaur body size changes leading to flight were complex, not a simple progression.

More Related Videos

Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila
06:00

Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila

Published on: October 1, 2011

Assessing Species-specific Contributions To Craniofacial Development Using Quail-duck Chimeras
09:38

Assessing Species-specific Contributions To Craniofacial Development Using Quail-duck Chimeras

Published on: May 31, 2014

Related Experiment Videos

Last Updated: Jul 11, 2026

Creating Avian Forebrain Chimeras to Assess Facial Development
04:10

Creating Avian Forebrain Chimeras to Assess Facial Development

Published on: February 18, 2021

Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila
06:00

Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila

Published on: October 1, 2011

Assessing Species-specific Contributions To Craniofacial Development Using Quail-duck Chimeras
09:38

Assessing Species-specific Contributions To Craniofacial Development Using Quail-duck Chimeras

Published on: May 31, 2014

Area of Science:

  • Paleontology
  • Evolutionary Biology
  • Dinosauria

Background:

  • Fossil evidence for dinosaur evolution leading to birds and flight has been limited.
  • Understanding theropod body size changes is crucial for reconstructing the origin of flight.

Purpose of the Study:

  • To investigate the body size trends in the dinosaur lineage leading to birds.
  • To determine if miniaturization or gigantism was ancestral in Paraves.

Main Methods:

  • Phylogenetic analysis of a new dinosaur fossil from Mongolia.
  • Comparative analysis of body size evolution across Dromaeosauridae and Troodontidae.

Main Results:

  • A new basal dromaeosaurid from Mongolia indicates extreme miniaturization was ancestral for Paraves.
  • Dromaeosaurids and troodontids, the closest relatives to birds, experienced four independent events of gigantism.
  • Some lineages increased in size by nearly three orders of magnitude.

Conclusions:

  • The evolution of theropod body size leading to avian flight was not a unidirectional process.
  • Miniaturization preceded flight evolution in the Paraves clade.
  • Gigantism in bird-related dinosaur lineages occurred independently and later in their evolutionary history.