
Concept explainers
To describe: The comparison and differences between Haeckel’s and Von Baer’s ways of thinking about changes in development over the course of animal evolution.
Introduction: Biologists from the nineteenth and twentieth centuries compared and described embryonic development of a diverse group of animals. They also described the ways in which the various morphogenetic processes in different groups of organisms result in different adult forms.

Explanation of Solution
Among the many first things, the biologists who were studying developmental biology learned that the embryos of many species are more often similar than the adults. Both Karl Von Baer and Ernst Haeckel studied embryo development to know more about the developmental pattern of organisms. In 1882, Karl von Baer noted that those features that are common to higher taxon appear early than those characters of lower tax such as families or order. According to Baer’s law, embryo development passes through the developmental stages of their adults. Haeckel also explained that the development of an organism, during the course of evolution, pass through all its adult form’s developmental stages.
Following are some differences in the way of thinking of these two biologists about changes in an organism’s development over the course of evolution:
To explain: The learning about phylogeny from development, even though Haeckel’s dictum seldom holds.
Introduction: Biologists from the nineteenth and twentieth century compared and described embryonic development of a diverse group of animals. They also described the ways in which the various morphogenetic processes in different groups of organisms result in different adult forms.

Explanation of Solution
Ernst Haeckel, a German biologist, interpreted developmental patterns to mean that an individual organism’s development repeats the evolutionary history of adult forms of their ancestors. It is known as “ontogeny recapitulates phylogeny”.
However, by the end of the 19th century, it was clear that Haeckel’s dictum seldom holds. For example, embryos of mammal and reptile go through a development stage where they have pharyngeal clefts and branchial arches identical to fish supporting that they share a common ancestor with fish. However, mammals and reptiles never acquire the characters of typical adult fish.
Nevertheless, these developmental studies provided information about the evolutionary relationship between different organisms. By studying embryo development, biologists identified many common developmental difference patterns among species.
Want to see more full solutions like this?
- can you help? I think its B but not surearrow_forwardSkip to main content close Homework Help is Here – Start Your Trial Now! arrow_forward search SEARCH ASK Human Anatomy & Physiology (11th Edition)BUY Human Anatomy & Physiology (11th Edition) 11th Edition ISBN: 9780134580999 Author: Elaine N. Marieb, Katja N. Hoehn Publisher: PEARSON 1 The Human Body: An Orientation expand_moreChapter 1 : The Human Body: An Orientation Chapter Questions expand_moreSection: Chapter Questions Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,... format_list_bulletedProblem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,... See similar textbooks Bartleby Related Questions Icon Related questions Bartleby Expand Icon bartleby Concept explainers bartleby Question Draw a replication bubble with two replication forks.blue lines are DNA single strands and red lines are RNA single strands.indicate all 3' and 5’ ends on all DNA single…arrow_forwardProvide an answerarrow_forward
- Question 4 1 pts Which of the following would be most helpful for demonstrating alternative splicing for a new organism? ○ its proteome and its transcriptome only its transcriptome only its genome its proteome and its genomearrow_forwardIf the metabolic scenario stated with 100 mM of a sucrose solution, how much ATP would be made then during fermentation?arrow_forwardWhat is agricuarrow_forward
- When using the concept of "a calorie in is equal to a calorie out" how important is the quality of the calories?arrow_forwardWhat did the Cre-lox system used in the Kikuchi et al. 2010 heart regeneration experiment allow researchers to investigate? What was the purpose of the cmlc2 promoter? What is CreER and why was it used in this experiment? If constitutively active Cre was driven by the cmlc2 promoter, rather than an inducible CreER system, what color would you expect new cardiomyocytes in the regenerated area to be no matter what? Why?arrow_forwardWhat kind of organ size regulation is occurring when you graft multiple organs into a mouse and the graft weight stays the same?arrow_forward
- What is the concept "calories consumed must equal calories burned" in regrads to nutrition?arrow_forwardYou intend to insert patched dominant negative DNA into the left half of the neural tube of a chick. 1) Which side of the neural tube would you put the positive electrode to ensure that the DNA ends up on the left side? 2) What would be the internal (within the embryo) control for this experiment? 3) How can you be sure that the electroporation method itself is not impacting the embryo? 4) What would you do to ensure that the electroporation is working? How can you tell?arrow_forwardDescribe a method to document the diffusion path and gradient of Sonic Hedgehog through the chicken embryo. If modifying the protein, what is one thing you have to consider in regards to maintaining the protein’s function?arrow_forward
- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning





