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IB DP Biology Populations and communities Study Notes | New Syllabus

IB DP Biology Populations and communities Study Notes

IB DP Biology Populations and communities Study Notes

IB DP Biology Populations and communities Study Notes at  IITian Academy  focus on  specific topic and type of questions asked in actual exam. Study Notes focus on IB Biology syllabus with guiding questions of

  • How do interactions between organisms regulate sizes of populations in a community?
  • What interactions within a community make its populations interdependent?

Standard level and higher level: 5 hours

IBDP Biology 2025 -Study Notes -All Topics

C4.1.1—Populations as interacting groups of organisms of the same species living in an area

Population refers to a group of individuals of the same species living in a given area. They normally interbreed with each other and don’t interbreed with other species. Populations can range from a few individuals to billions. They are often separated by geographical barriers, like the sea separating islands.

Population interactions include competition for resources and cooperation. Emergent properties arise from these interactions. For instance, in a herd, individuals interact to minimize predation risk. Predator-prey interactions often occur at the herd’s edges. Individuals within the herd can move to reduce their chance of predation.

A single individual, like Lonesome George, the last Pinta Island tortoise, cannot be considered a population as it cannot interbreed.

C4.1.2—Estimation of population size by random sampling

Estimating population size is often challenging due to the vastness of populations and the difficulty of counting individuals. Random sampling is a technique used to estimate population size by selecting a representative sample. This involves randomly choosing individuals from the population, ensuring that each individual has an equal chance of being selected. By analyzing the sample, researchers can make inferences about the entire population.

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