Question

1) Describe the data shown below in 2-3 sentences. 2) What type of relationship appears to exist between (explain your answer): Species 1 and 3: Species 2 and 3 Species 1 and 2 3) Draw expected growth curves for the three species in co-cultures and monocultures: 4) Do you think that any of the organisms effect the carrying capacity of the culture in three species co-culture compared to monocultures? Why or why not? How would you expect the curves drawn in your answer to question 3 to change if Species 3 was competing with Species 1 and 2? 5) In the experiment shown below Species 1 and Species 2 were grown in monocultures using medium that had first been used to culture Species 3, then Species 3 was removed (conditioned medium) or regular medium (unconditioned medium). incond. Mediwm Cand mediun 6) Describe the results shown in the figure above in 2-3 sentences 7) Write a testable hypothesis based on the results shown above:

Answer 1

  
cfu/ml species -fl species -2 -f2species -f3 2 species 2 species 3 species

Ans. 1. The above data represent the interspecies relationship between three species. At first, they are cultured in monoculture and CFU/ml was estimated. Then growth estimation was done for co-culture of two species (f3-f1 and f3-f2) and finally for the culture of three species(f3-f1-f2). By closely analyzing the above data we can correlate the behavioral correlation between species.

Ans.2

Species 1 and 3 --- Commensalism --- Because the growth of species 1 is increased where species 3 unaffected in co-culture

Species 2 and 3 --- Commensalism ---- Because the growth of species 2 is increased where species 3 unaffected in co-culture

Species 1 and 2 --- amensalism ---- Because the growth of species 3 is decreased where species 2 unaffected in co-culture.

Ans.3 The graph shown below is of species grown in monoculture and co-culture.

cfu ml cfu ml cfu ml Species 1 Species 2 Species 3 ecies 2 Species 1 Species 3 cfu /ml time

Ans 4 .  Yes species 3 increases the carrying capacity of co-culture as in the presence of species 3 the growth of species 1 and species 2 increase.

Ans5. If the species 3 is in competition which species 1 and 2 It no longer increases the growth but decreases it change it to below mentioned graph

Species 3 Species 1 Species 2 cfu ml time

Ans 6.

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The result above shows that species 3 has a commensalism behaviour for species 1 and 2, conditioned media obtained from the species 3 increases the growth of species 1 and 2. This may be due to nutritional enrichment of medium by degrading components that can be utilised by species 1 and 2 that they are unable to utilise in monoculture conditions. Result above clearly suggest that condition media of species 3 promotes the growth of the other two species.

Ans 7 All the above data shows that these three species have a inter-species relationship species 3 have a growth promoting effect on species 1 and 2. whereas species 1 decreased the growth of species 2. so it can hypothesis that in a co-culture condition species 2 dominates over species 1 and 3 .