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Presentatioin on have human actions changed the course of evolution


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Presentatioin on have human actions changed the course of evolution

  1. 1. Have Human Actions Changed The Course Of Evolution? Presented By: Raunak Roy Department Of Zoology
  2. 2. • The universe in its very fabric is inherently complex and to this end, evolution yields complexity in organisms. • Hence, Change is both inherent and inevitable. • Evolutionary change would
  3. 3. • Molecular Clock Hypothesis was proposed by Emile Zuckerland and Linus Pauling based on the observation that the rate of evolutionary change of any specified protein was approximately constant over time and over different lineages. • Motoo Kimura‟s theory on evolution occurring through neutral mutations which in turn
  4. 4. Have Human Actions Changed The Course Of Evolution? Evolutionary processes may have general patterns but the process itself doesn‟t have a “fixed course”. The late Stephen Jay Gould has written that if we were to rewind the “tape” of evolutionary history and play it
  5. 5. • Random processes play a major role in biological evolution. Mutations that were present at the right time, in the right species, in the right environment. • Without a path one can‟t go astray • Evolution has no “fixed course” or “fixed goal”, because, science defines no purpose for nature and natural processes. • Humans are a product of these very processes therefore “human actions”
  6. 6. Human actions aren‟t always detrimental…• Research on Heteropteran species in the Canary Islands suggest that agriculture has led to an increase in species richness. • New plants introduced by humans were
  7. 7. • The results were obtained using Bonferroni sequential test. • Indicated that the number of species of heteroptera followed a linear regression with: o No. of plant species o No. of inhabitants o Total cropland surface o No. of natural habitats A direct anthropogenic factor Increased due to introduction of non endemic flora for agriculture
  8. 8. • Research on fishes in world river systems. Data was compiled from 1055 river basins worldwide.
  9. 9. • Three major hypotheses, which are not necessarily mutually exclusive, have been proposed to explain the establishment of non-native species: • The „„human activity‟‟ hypothesis, which argues that human activities facilitate the establishment of non-native species by disturbing natural landscapes and by increasing propagule pressure; • The „„biotic resistance‟‟ hypothesis, predicting that species-rich communities will readily impede the establishment of non-native species;
  10. 10. • Results show that the human activity indicators account for most of the global variation, associated with increase in non-native species richness, which is highly consistent with the „„human activity‟‟ hypothesis. In contrast, our results do not provide support for either the „„biotic acceptance‟‟ or the „„biotic resistance‟‟ hypothesis.
  11. 11. • Research on species diversity pattern in the US of plants indicate that the number of established non- native plant species per state does tend to outpace the number of extinct and threatened species per state. The net gain in plant species is strongly
  12. 12. • Many animal and plant species have adapted to the new stresses, food sources, predators and threats in urban and suburban environments, where they thrive in close proximity to humans. Their success provides researchers with valuable (and sometimes unexpected) insights into evolutionary and selective processes. Because these adaptations have had to be rapid, cities are, in some
  13. 13. • For species that rely on sound to communicate or execute mating strategies, noise pollution presents a problem. Extensive studies on songbirds show how many species have adapted by adjusting various aspects of their song to overcome residual noise. • They can adjust the amplitude of their song to overcome anthropogenic background noise. Such noise is most pervasive at lower frequencies, and it is therefore unsurprising that song sparrows, for example, have been found to raise the frequency of their low notes
  14. 14. Even if it is negative, it is natural… • Evolutionary processes like natural selection (even if the selection pressure is of anthropogenic origin) is not like “mother Nature” watching over us. It is a completely impersonal process. • The notion that many species are adversely affected by human actions, and that this is “bad” is a matter of perspective. For, even in
  15. 15. • The impact of mankind on biodiversity has clearly been detrimental to many animals and plants, but the story is more complex and subtle than has been appreciated. • Urbanization provides ready-made laboratories for studying evolution and adaptive processes, and examining the influence of humans on flora and fauna creates the potential to mitigate any negative effects. • According to John Marzluff, a professor
  16. 16. Thank you
  17. 17. Research Literature cited: