Presentatioin on have human actions changed the course of evolution

Have Human Actions Changed The Course Of

Evolution?

Presented By:Raunak RoyDepartment Of Zoology

• 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 occur, with or without human

• Molecular Clock Hypothesis wasproposed by EmileZuckerland and Linus Paulingbased on the observation that therate of evolutionary change of anyspecified protein wasapproximately constant over timeand over different lineages.

• Motoo Kimura‟s theory onevolution occurring throughneutral mutations which in turnresult from the RNA “wobble” and

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 again, the results would not be the

• 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” are as natural as any other action by

Human actions aren‟t always detrimental…

• Research onHeteropteranspecies in theCanary Islandssuggest thatagriculture has ledto an increase inspecies richness.

• New plantsintroduced byhumans wereexploited by the non

• The results were obtained using Bonferronisequential 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 habitatsA direct anthropogenic factor

Increased due tointroduction of nonendemic flora foragriculture

• Research on fishes in world river systems. Data was compiled from 1055 river basins worldwide.

• Three major hypotheses, which are notnecessarily mutually exclusive, havebeen proposed to explain theestablishment of non-native species:

• The „„human activity‟‟ hypothesis, whichargues that human activities facilitatethe establishment of non-native speciesby disturbing natural landscapes and byincreasing propagule pressure;

• The „„biotic resistance‟‟hypothesis, predicting that species-richcommunities will readily impede theestablishment of non-native species;and

• 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.

• Research on speciesdiversity pattern inthe US of plantsindicate that thenumber ofestablished non-native plant speciesper state does tendto outpace thenumber of extinctand threatenedspecies per state.The net gain in plantspecies is stronglyand positively

• Many animal and plant specieshave adapted to the newstresses, food sources, predatorsand threats in urban and suburbanenvironments, where they thrive inclose proximity to humans. Theirsuccess provides researchers withvaluable (and sometimesunexpected) insights intoevolutionary and selectiveprocesses. Because theseadaptations have had to berapid, cities are, in somerespects, ideal laboratories for

• For species that rely on sound tocommunicate or execute matingstrategies, noise pollution presents aproblem. Extensive studies on songbirdsshow how many species have adaptedby adjusting various aspects of theirsong to overcome residual noise.

• They can adjust the amplitude of theirsong to overcome anthropogenicbackground noise. Such noise is mostpervasive at lower frequencies, and it istherefore unsurprising that songsparrows, for example, have been foundto raise the frequency of their low notesand concentrate their energy on high

Even if it is negative, it is natural…

• Evolutionary processes like naturalselection (even if the selectionpressure is of anthropogenic origin) isnot like “mother Nature” watchingover us. It is a completely impersonalprocess.

• The notion that many species areadversely affected by humanactions, and that this is “bad” is amatter of perspective. For, even inconservation efforts the end goal is to

• The impact of mankind on biodiversityhas clearly been detrimental to manyanimals and plants, but the story ismore complex and subtle than hasbeen appreciated.

• Urbanization provides ready-madelaboratories for studying evolution andadaptive processes, and examining theinfluence of humans on flora and faunacreates the potential to mitigate anynegative effects.

• According to John Marzluff, a professorof wildlife science at the University of

Thank you

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