Climatic Changes

Thoughts

1. Is there any hint of glacial cycles or change of temperature in the Quran?
2. Figs and olives, mentioned in the Quran, do they have anything special with regards to their evolution?
3. The general Western view has been that humans have had a negative impact on earth and the environment. The call has been for attempting to reduce or neutralize, if ever possible, the harmful effect humans have on the environment. The Islamic view, as it shows in the Quran, has a different perspective. The Quran sees humans as either destroyers or carers and reformers. Islam advocates the latter. The Islamic view therefore is that humans not only can reduce or neutralize their negative impact on earth and the environment but can, and should, through their actions, enhance and maintain such environment to become even better!
4. It would be cool if I pay a visit to the tropics! I feel a deep connection to such places.
5. I should go live and teach (ecology) in Sudan!
6. I am against the author's view of historic accidents and that plants are not well adapted to their environments.
7. The lush vegetation that had been present in place of the current deserts in Egypt at the time of Ancient Egyptians, were they a result of climatic cycles? Was their disappearance manmade or natural?
8. Does the concept of succession, popular in permaculture, have anything to do with the succession of plants and their evolution with time in a particular geographical location?

Digest

• "Changes in climate have occurred on shorter timescales than the movements of land masses."
• "Much of what we see in the present distribution of species represents phases in a recovery from past climatic shifts."
• "Changes in climate during the Pleistocene ice ages ... bear a lot of the responsibility for the present patterns of distribution of plants and animals."
• Technology for discovering, analyzing and dating biological remains is becoming more sophisticated particularly by the analysis of buried pollen samples.
• "Techniques for the measurement of oxygen isotopes in ocean cores indicate that there may have been as many as 16 glacial cycles in the Pleistocene, each lasting for about 125,000 years."
• "Each glacial phase lasted for 50,000 to 100,000 years, with brief intervals of 10,000 to 20,000 years when the temperatures rose close to those we experience today."
• "During the 20,000 years since the peak of the last glaciation, global temperatures have risen by about 8°C."
• "The rate at which vegetation has changed ... has been detected by examining pollen records."
• Sequence of trees invading:
• spruce
• jack pine or red pine
• white pine
• oak
• hemlock
• chestnut
• Forests expand as glaciers retreat! Forests are still expanding till this day!
• Impact on much smaller space and time scales takes place when high discharge events (associated with storms or snow melt) result in a very small-scale mosaic of patches.
• "The stream fauna may rarely achieve an equilibrium between flow disturbances."
• Similar changes also show up in Asia, Africa and South America.
• "Particular ‘hot spots’ of species diversity are likely sites of forest refuges during the glacial periods, and sites of increased rates of speciation."
• "Global warming, maybe 3°C in the next 100 years, is predicted to result from continuing increases in atmospheric carbon dioxide."
• The extinction of the Picea critchfeldii tree in the Quaternary occurred around 15,000 years ago at a time of especially rapid postglacial warming.
• "Even more rapid change in the future could result in extinctions of many additional species."

Glacier melting

Questions

1. Is the current rise in global temperature really attributed to manmade activities or is it just a natural oscillation of temperature inline with temperature variation cycles like those that have been occurring in the distant past?
2. What effect has repeated climatic change had in the distant past on species and what role has it played, if any, in their evolution?

Movements of Land Masses

Thought

After a deep, and heated, discussion it became clear to me that the theory of evolution of species does not conflict with the verses of the Quran or what Islam teaches.

Digest

• Movement of continents:
• The wide dispersion of related species across continents first led biologists to suggest that continents were adjacent to one another in the past and have moved apart later on. This view was advocated early in 1915 by Alfred Wegener.
• Geologists first resisted such view until geomagnetic measurements confirmed this. "The discovery that the tectonic plates of the earth’s crust move and carry with them the migrating continents, reconciles geologist and biologist."
• The following large flightless birds are one example of widely distributed yet related organisms:
• South America: rhea and tinamou
• Australia: cassowary and emu
• New Zealand: kiwi
• Africa: ostrich
• Continents moved apart along millions of years (the past 150 to 10 million years ago).
• "Changes in temperature in the North Sea over the past 60 million years. During this period there were large changes in sea level that allowed dispersal of both plants and animals between land masses."
• Gondwanaland is one of the two ancient supercontinents that have split about 150 million years ago.
• "Molecular techniques make it possible to analyze the time at which the various flightless birds started their evolutionary divergence."

Cassowary

Question

Was the wide dispersion of species really why it was first suggested that currently far away land masses have moved away from one another and were in the past adjacent?

Islands and Speciation

Thoughts

1. The theory of evolution of species and what Islam and the Quran teach, how can they be reconciled?
2. In Upper Egypt, people are more isolated then those in the Nile Delta area. What effect, if any, does this have on them?
3. Taking plant species from such remote islands and reintroducing them elsewhere would be an interesting idea.
4. Breeding, of animals, taken from elsewhere can be interesting.
5. 'Specialization' of humans when isolated.
6. Specialization of coexisting humans.
7. How and why do populations diverge despite being in the same geographic location?

Digest

• Galápagos Islands are volcanic islands
• Location: Isolated in the Pacific Ocean about 1000 km west of Ecuador and 750 km from the island of Cocos, which is itself 500 km from Central America.
• Description: At more than 500 m above sea level the vegetation is open grassland. Below this is a humid zone of forest that grades into a coastal strip of desert vegetation with some endemic species of prickly pear cactus (Opuntia).
• Darwin's finches: Fourteen species of finch are found on the islands.
• Microsatellite: The evolutionary relationships amongst them have been traced by molecular techniques
• The 14 distinct species of finches differ in shape and feeding habits.
• Isolation of individual islands within the archipelago has led to the evolution of a series of species each matching its own environment.

Small ground finch (Geospiza fuliginosa)

Questions

1. How do populations specialize despite not being geographically separated?
2. What islands, other than land surrounded by water, exist? (Oases?)
3. Let's explore the interesting subject of rare and specialized species in isolated islands and the process by which they evolve!

What do we Mean by a Species?

Thoughts

1. Gog and Magog, are they different species from humans?
2. Therefore, by definition, humans all belong to the same species.
3. Have Gog and Magog specialized and becomes a different species than humans due to isolation?
4. What about isolated communities like in Siwa, Nubia and other more isolated ones such as in Islands (belonging to India for instance where contact has been attempted yet unsuccessfully).
5. Hybridization in American population, what does it lead to.
6. Inadvertent hybridization of F1 hybrids with other forms of the same species or hybridization among different cultivars of a plant may result in unfavorable results in offspring.
7. What is a cultivar? (A form of ecotype?)
8. Isolated communities of humans, like Siwa and Nubia, have imposed cultural rules of not marrying from outside their communities.
9. Donkeys and horses produce infertile mules when they mate. This fits them perfectly within the definition of being two distinct species (two distinct biospecies).

Hybridization against forces of natural selection

Digest

• Speciation, the forming of distinct species, is a process not a sudden event
• Hybridization and natural selection are two opposing forces
• According to the Mayr-Dobzhansky test, two organisms belong to the same biospecies if they could breed together in nature to produce fertile offspring
• Allopatric speciation vs sympatric speciation
• Ecological speciation is speciation driven by divergent natural selection in distinct subpopulations according to Dolph Schluter (2001)
• Stages of speciation (in the most orthodox view of ecological speciation):
1. Two subpopulations become geographically isolated and natural selection drives genetic adaptation to their local environments
2. Reproductive isolation (pre-zygotic or post-zygotic) builds up between the two subpopulations
3. The two subpopulations re-meet in a phase of secondary contact
4. The hybrids between individuals from the different subpopulations are now of low fitness. Natural selection will then favor any feature in either subpopulation that reinforces reproductive isolation preventing the production of low fitness hybrid offspring. These breeding barriers then cement the distinction between what have now become separate species.
• In northern Europe, the lesser black-backed gull and the herring gull are now two distinct species. They do not hybridize and are therefore true biospecies.  Their 'ancestors' still hybridize freely after spreading east and west from Siberia.

European herring gull (top) and lesser black-backed gull (bottom)

Questions

1. So, what exactly is a species?
2. So, ecotypes are different forms of the same species? Also different forms, like peppered moths (melanic and nonmelanic) belong to the same species?
3. How come species are classified by scientists then reclassified later on in a different way?