Evolutionary biology

For Darwin, comparative embryology was important evidence in support of the evolution of descendants from a common ancestor. In 1874, the German biologist Ernst Haeckel followed Darwin’s line of thinking with the notion that ancestral developmental processes are repeated during embryonic development, and are a record of evolutionary ancestry … ‘Ontogeny (development) recapitulates phylogeny (evolutionary history)’ …  the biogenetic law that dominated evolutionary thinking in the late 19th century.

Often misinterpreted as referring to the recapitulation of adult forms rather than the forms of embryo, Walter Garstang at Leeds University, highlighted the problems of recapitulation theory in 1921, by pointing out that an adult cannot evolve directly into another adult. According to Garstang, embryonic development represents the stages of ancestors to whatever point it was in ontogeny when divergence into new forms occurred. In effect ‘Ontogeny does not recapitulate phylogeny – it drives it’. He realised that the larval stages of adult forms of many animal taxa were, according to Henson (personal communication), precociously hatched embryos. Subject to Darwinian selection, larvae are potentially the nodes for major evolutionary innovation as the result of selection of larval characteristics consequently affecting adult morphology/physiology in subsequent generations.

Today, investigating the gene interactions controlling development and how these have changed through time resulting in the evolution of new taxa is now possible using the techniques of molecular genetics. Arkhat Abzhanov at Imperial College, UK et al have unravelled the intricacies of the genetic interactions controlling beak development in Darwin’s finches deepening our understanding of how new finch species/sub-species have evolved from a common ancestor arriving on the islands from South America about two million years ago.

Evolutionary-developmental biology (evo-devo) highlights how the interactions between genes might affect the micro- and macro-evolution of lineages (e.g. Darwin’s finches, larval forms). Today, the emerging discipline reframes the arguments of earlier evolutionary thinking, adding molecular biology to our understanding of how developmental processes influence evolution. The sessions explore a synthesis of these ideas to reassess the nature of evolution in process.

Session titles:

1. Evolution through Natural Selection
2. Development and evolution 
3. Larval Forms   
4. Galapagos Tales  
5. The Tales continue

All course content will be delivered online via the Virtual Learning Environment (VLE). You will be taught largely through a series of pre-recorded talks (which may be audio and/or video), designed to help you address different aspects of the main topic. You will normally have access to a range of useful resources and suggested activities.

There will also be an element of interactive work, and the opportunity for you to engage in written form with other course participants and discuss questions set by the Course Director via the Course Forum. The Course Director will generally respond to a selection of key questions and comments on a daily basis.

Some courses may also have elements of optional live discussions via Zoom.

There are no pre-requisites for courses, unless specified, and all are open to adult learners over 18 years old. Courses are taught at approximately first-year undergraduate level.

Content will be made available on each day of the course, Monday to Friday, from 8.00am BST. Course content will normally amount to c 1.5hrs per day across the 5 days, comprising of material delivered by the Course Director and activities/reading set, which would include discussions via the course forum. You may also need to complete reading or other preparation suggested in advance of the course.

We therefore suggest that you set aside approximately 1.5 hours of study per day to complete each day’s content and activities. However, this does not need to be done in one sitting, and you have the flexibility to access content when and where you want, and to go back and review it as often as you wish. Each course runs for one week and content will remain available to access on the VLE for 2 weeks after the course has finished.

A Certificate of Participation for the course(s) will be sent electronically, upon request via email, after the end of the Summer Festival. Details will be provided on the VLE.