C4.1  Populations and Communities

Guiding Questions:  
Guiding questions help students view the content of the syllabus through the conceptual lenses of both the themes and the levels of biological organization.

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

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​Linking Questions:  
Linking questions strengthen students’ understanding by making connections between topics.  The ideal outcome of the linking questions is networked knowledge.

• What are the benefits of models in studying biology?
• What factors can limit capacity in biological systems?

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Resources:

• ​Quizlet study set for this topic.  Coming soon!

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

• Define population. 
• State what isolates populations of the same species.​

​C4.1.2— Estimation of population size by random sampling.

• Define sample.
• Outline the purposes of sampling a population.
• Define sampling error. 
• Describe the need for randomness in sampling procedures. 
• Compare sampling methods for sessile vs motile organisms.

C4.1.3-- Random quadrat sampling to estimate population size for sessile organisms.

• Outline the use of quadrat sampling to estimate the population of a sessile organism.  

C4.1.4— Capture–mark–release–recapture and the Lincoln index to estimate population size for motile organisms.

• Describe the method of capture- mark- release-recapture sampling to estimate the population of a motile organism.  
• List assumptions made about the population when using mark-recapture methods to estimate population size. 
• Outline use of the Lincoln index to estimate population size from mark-recapture data.  ​

​C4.1.5—  Carrying capacity and competition for limited resources. 

• Define carrying capacity.
• List examples of resources that may limit the carrying capacity of a population. ​​

​C4.1.6- Negative feedback control of population size by density-dependent factors.

• Outline population size control as an example of a negative feedback loop. 
• Distinguish between density- dependent and density- independent factors that control population size. 
• List examples of density- dependent factors that maintain population  carrying capacity.
• Outline examples of density- independent factors that maintain population  carrying capacity.

C4.1.7-  Population growth curves.

• State that species have the ability to produce more offspring than the environment can support.
• Outline conditions in which populations can grow exponentially. 
• Explain the reasons for the pattern of sigmoid population growth curve.
• ​Sketch and annotate a graph of the sigmoid and exponential growth curves. 
• Outline the use of a logarithmic scale when plotting change in population over time.

​C4.1.8- Modelling of the sigmoid population growth curve. 

• Outline a method for monitoring the population of yeast or duckweed over time.
• Use data of yeast or duckweed population over time to compare observed and expected population growth curves.
  

C4.1.9- Competition versus cooperation in intraspecific relationships.

• Define intraspecific relationship.
• Outline cause and effect of competition in a population.
• Outline cause and effect of cooperation in a population. 
• List examples of competition and cooperation in plant and animal populations. 

​C4.1.10-  A community as all of the interacting organisms in an ecosystem.

• Define community.
• Give an example of a community of organisms.

C4.1.11- Herbivory, predation, interspecific competition, mutualism, parasitism and pathogenicity as categories of interspecific relationship within communities.

• Outline the ecological interactions within biological communities.  Include mutualistic (++), competition (--), predation (+-), herbivory (+-), parasitic and pathogenic interactions (+-).
• State an example of mutualistic (++), competition (--), predation (+-), herbivory (+-), parasitic and pathogenic interactions (+-).

​​​C4.1.12- Mutualism as an interspecific relationship that benefits both species.

• Outline the mutualistic relationship within root nodules in Fabaceae (legume family).  
• Outline the mutualistic relationship within mycorrhizae in Orchidaceae (orchid family).
• Outline the mutualistic relationship of zooxanthellae in hard corals.

C4.1.13- Resource competition between endemic and invasive species.

• Define endemic and invasive species.  
• Describe the effect of invasive species on the realized niche of an endemic species. 
• Outline the competition for resources in an example of endemic and invasive species.

C4.1.14- Tests for interspecific competition.

• Explain the methodology and limitations of using a chi-square test to assess presence of interspecific competition in a community.
• Explain the use of direct experimentation to assess the presence of interspecific competition in a community.

C4.1.15- Use of the chi-squared test for association between two species.

• State the null and alternative hypothesis of the chi-square test of association between species in a community.
• Use a contingency table to complete a chi-square test of association between species in a community.​

C4.1.16- Predator–prey relationships as an example of density-dependent control of animal populations.

• Explain the typical dynamic equilibrium of populations of predator and prey. 
• Describe an example of an oscillating cycle of predator and prey population sizes.​

C4.1.17- Top-down and bottom-up control of populations in communities.

• Compare and contrast top-down and bottom-up control of populations in communities. ​

​​​​C4.1.18- Allelopathy and secretion of antibiotics.

• Define allelopathy.  
• Outline an example of allelopathy.
• Define antibiotics.
• Outline an example of the natural production and function of antibiotics.  ​