Question

a scientist is growing a population of bacteria in a Petri dish. The dish is set up with a growth medium and bacteria and then left alone. No additional nutirents are added, ad there is no way for dead organisms to be recycled back into the ecosystem. The graph represents the population of bacteria in the first few days after being added to the dish. What will happen to the graphed line a few days after the population reaches carrying capacity?

Answer 1

The bacteria population will reach a stable state after reaching carrying capacity, with fluctuations around the stable size due to births, deaths, mutations, and potential disruptions.

The graphed line representing the population of bacteria will eventually reach a stable state after the population reaches carrying capacity. This is because, in a closed system with no additional nutrients or recycling of dead organisms, the population size cannot grow indefinitely.

Here's what will likely happen:

1. Population Overshoot: Initially, the graph will show a steep exponential growth as the bacteria utilize the available resources rapidly. This phase is known as the "exponential growth phase."
2. Carrying Capacity: As the available resources start to deplete and competition increases for those resources, the growth rate will eventually slow down. This point where the population stabilizes at the maximum number it can support given the available resources is called the "carrying capacity."
3. Equilibrium: Once the population reaches carrying capacity, the birth rate and death rate will balance out. The graph will reach a plateau, indicating a relatively stable population size. However, even at equilibrium, there will be fluctuations in the population as individuals are born and die.

Additional factors to consider:

1. Mutation: Random mutations can occur in the bacteria, potentially leading to new strains with different characteristics. This could affect the carrying capacity or the population dynamics.
2. Dormant stage: Some bacteria can enter a dormant stage in response to unfavorable conditions. This could result in a temporary decrease in the population size as measured in the graph.
3. Unexpected events: The closed system could be disrupted by unexpected events like contamination or changes in temperature, impacting the population size and stability.

Overall, while the exact future behavior of the graphed line is dependent on various factors, it is expected to eventually reach a stable state with fluctuations around the carrying capacity in a closed system with limited resources and no recycling of dead organisms.