Why vs what? Tinbergen’s 4 questions
1. What is it for?
2. How di dit develop during the lifetime of the individual?
3. How did it evolve over the history of the species?
4. How does it work?
Fisheries Biology
- Genetic consequences of selective harvesting
How does selective harvesting affect the future of fisheries?
- Genetic consequences of hatcheries
How do hatchery raised fish affect wild stocks?
Conservation Biology
- Identification of evolutionary significant units
- Avoidance of inbreeding depression in captivity
- Avoiding the loss of adaptive variation (adaptive rescue)
- Identification of minimal population size for viability
- Predicting the response to global change
Human health
- Evolution of pathogens and antibiotic resistance
- Understanding gene function through comparative study
- Tracing the origin and spread of infectious diseases
Ebola
- Detection of nucleotides changes responsible for genetic disorders from gene
genealogies
- Long-term consequences of medical intervention
Pharmaceutical industry:
- Drug design by in vitro of in vivo evolution
- Targeted searches for natural products: bio=prospecting
- Evolution of antibiotic resistance
Agriculture
- Crop and livestock improvement by selective breeding
- Evolution of pesticide resistance
- Transgenic organisms – advantages and risks
1
,Primary goals of Evolutionary Biology:
- To document evolutionary history. How has life changed through time?
- To understand the mechanisms that drive biological change through time
- To apply this knowledge to understand the genetic underpinnings of biological
diversity, and to solve practical problems in the life sciences.
What is evolution?
- Descent with modification
- Changes in the properties of populations that transcend the lifetime of a single
individual
- Changes in allele frewuenties over time
- Key ingredients:
Change that is heritable across generations
A property of populations, not individuals
All evolving systems have the following properties:
- Populations: groups of entities
- Variation: members of the population differ from one another with respect to some
characteristic
- Hereditary similarity: offspring resemble parents
Historical background
- Aristotle (384-322 bc) – believed that all living organisms could be arranged in a
‘scale of nature’ or great chain of being. The ladder of life consists of graduation from
inanimate material through plants, through lower animals and humans to other
spiritual beings.
Before Darwin ( and other early developers )
- Orthodoxy – species as fixed, designed by God
- Variation = imperfection
- Young earth
- But evolutionary thinking beginning
Carolus Linnaeus (1707-1778) – Established the modern system of taxonomy in an attempt
to discover order in the diversity of life ‘for the greater glory of God’
- Groupings based on similarity
- Hierarchal relationships of organisms
Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck
- First articulated theory of evolution:
Organisms continually arise by spontaneous generation
‘Nervous fluid’ acts to move each species up the ‘great chain of being’/ No
extinction, just continuous change.
Organisms develop adaptions to changing environment through the use and
disuse of organs (heavy use attracts more ‘nervous fluid’)
Acquired characteristics are inherited
2
, Problems with Lamarck’s ideas:
1. There is no evidence of spontaneous generation and plenty for extinction
2. There is no evidence of an innate drive towards complexity
3. There is no evidence of inheritance of acquired characteristics (at least in the way
Lamarch intended)
Charles Lyell – Principles of Geology
Emerging field of geology lead to a new concept of the age of the Earth
- The history of the earth extends back through vast time periods
- The processes at word today are the same as those that have been operating throughout
the entire history of earth
These concepts became known as Uniformitarianism
Charles Robert Darwin (1809-1882)
- Briefly studied medicine at Edinburgh
- Studied for the clergy at Christ’s College, Cambridge University
- Interacted with some natural scientists (John Henslow and Adam Sedgwick) at
Cambridge
- Offered a position (in 1831) as the ship’s naturalist on the H.M.S. Beagle, which was
going on an expedition to chart the waters of South America
Variation in Bill shape among Galapagos finches
- Closely related species that occupy different ecological settings tend to have different
characteristics
- Populations that are physically isolated tend to differ
Observations from domestic animals:
- High levels of variability within a species
- Variants can pass these characteristics to offspring
Artificial selection can rapidly alter the characteristics of a breed
3