Download 5. Evolution and extinction of biological population by Dr Snigdhadip

Evolution to the rescue
Snigdhadip Dey
École normale supérieure, Paris
Maison de l’inde, 3rd July 2015
Sketch of the talk
• What is evolution?
• Charles Darwin and his theory of evolution by natural selection.
• Practical applicability of evolutionary research.
• Causes and consequences of species extinction.
• My research.
Charles Darwin
(1809-1882)
Evolution by
Natural Selection
What Darwin did?
• Proposed a theory on how
evolution works by natural
selection.
• Gathered plenty of evidences
to support his theory.
Darwin´s voyage
• Invited to travel around the globe as a
naturalist (1831-1836).
Darwin´s voyage
Darwin´s research
• Darwin found many unique species in Galapagos.
• Each island had its own species of tortoises
and birds that were distinctly different from
other islands.
• Studied fossils to find evidences that living
creatures changed over time
• Embryological evidences.
Ontogeny recapitulates phylogeny – Earnst Haeckel
How does natural selection work?
Darwinian vs Lamarckian giraffe
Why do you need evolutionary ideas??
Evolutionary medicine:
Antibiotic resistance
Understanding how antibiotic
resistance evolves
Agriculture:
• Improving the quality of crop and livestock by artificial selection.
• Understanding the evolution of pesticide resistance.
Fishery :
• How does selective harvesting affect the future of fisheries?
• Improving the quality and yield via artificial selection.
Conservation Biology:
Adaptive potential to withstand global change.
More efficient
Drug designing
The tree of life
Species Extinction : unfortunate facts
• According to the fossil record, 2-4% of the species that have ever lived survive today.
• Rapid loss of species in recent time is estimated to be between 1000 and 10,000 times higher
than the “background” or expected natural extinction rate.
International Union for Conservation of Nature (IUCN)
How does extinction affect ?
• Loss of biodiversity results in disruption of the balance of the ecosystem (water cycling, soil
formation and retention, resistance against invasive species, plant pollination, climate
regulation and pollution control.
• The monetary value of goods and services provided by ecosystems is estimated to amount to
some 33 trillion dollars per year – nearly twice the global production resulting from human
activities.
(IUCN)
Major threats to biodiversity
• Habitat destruction and degradation
• Over-exploitation (extraction, hunting, fishing etc.)
• Pollution
Can populations adapt to these threats?
• Disease
• Global climate change
(IUCN)
Real-time evolution in the laboratory!!
Artificial speciation in the laboratory!!
• One of the first to carry out a controlled
evolution experiment was William Dallinger.
• During the course of a seven year-long (1880–
1886) experiment, Dallinger slowly increased
the temperature from 60 °F to 158 °F.
Dodd (1989)
My voyage so far…..
Dr. Amitabh Joshi
Dr. Henrique Teotónio
How do populations adapt to
fluctuating environments?
What are maternal effects?
Maternal
environment
Maternal
genotype
Maternal
phenotype
Heredity
maternal effects
Offspring
genotype
Offspring
environment
Offspring
phenotype
Anticipatory maternal effects in fluctuating environments:
Maternal effects
Maternal
phenotype
Maternal
environment
Predictable
fluctuation
Unpredictable
fluctuation
Maternal
bet-hedging
strategy ??
Offspring
phenotype
Offspring
environment
Anticipation
N
N
A
A
N
A
A
N
N
A
A
N
A
N
N
N
A
A
A
N
N
A
N
N
A
A
N
N
A
A
A
N
N
Does exposure to controlled fluctuating environments
in the laboratory facilitate the evolution of maternal effect
and consequent adaptation to fluctuating environments?
Design of the experiment
A
= Anoxia stress
N
= Normoxia
Predictable
N
A
N
A
N
A
N
A
N
A
A
N
N
A
N
A
N
......... (60 generations)
Unpredictable
N
N
A
A
N
A
N
N
A
A
N
N
A
N
A
A
N
...... (60 generations)
de novo evolution of anticipatory maternal effect
Predictable
Unpredictable
Mother
A
N
Offspring
A
A
How does the maternal effect work?
The hypothesis
Mother
N
Offspring
Glycogen allocation
in the eggs
Better performance in
A
Evolution of anticipatory glycogen provisioning
Predictable
A
N
Mother
Perspective: is evolution of maternal effect favourable in
fluctuating environments in general?
Maternal effects improve future performance of the populations in an array of
fluctuating environments.
Conclusions
Populations exposed to predictably fluctuating
environments adapted by evolving maternal effects. While
the ones exposed to unpredictably fluctuating environment
failed to do so.
The maternal protection from anoxic stress is due to an
adaptive glycogen provisioning to the oocytes.
We have evolved so much that we are studying evolution!!
But have we evolved enough to save ourselves from extinction?
Thank you