This week, in preparation for your research projects and your visit from Mark (on Monday!), I would like you to review some of the topics we covered on Wednesday concerning the scientific method. To start, watch this video and explore the resources on this site. On the Science buddies website, be sure to scroll all the way down and read through the first four rows of the table they provide, clicking on the links in the right-hand column to learn more about each topic. The information on this page is very good and useful, so please review it carefully. Don't worry about the rows after # four, we'll cover that information later on. After you watch the video, see my caveat comment below. I want you to think carefully about the differences between hypotheses and predictions.
Once you have completed reviewing the materials, please respond in the Comments section with the following:
What is one of your research questions that you would like to ask for your research project?
What are your hypotheses to potentially answer your research question?
What are your predictions from each of your hypotheses?
While here I ask you for one research question, you might have multiple hypotheses to answer the question, and each hypothesis could have multiple alternative predictions (remember the hypothetico-deductive method).
I'll give you one quick and simple example:
Research question: Is there a difference in the number of bat species found in large, continuous forest and small forest fragments?
Null Hypothesis: There is no difference in the number of bat species in continuous and fragmented forest.
Alternative Hypothesis: There is a difference in the number of bat species in continuous and fragmented forest.
Prediction 1: There are more species in continuous forest than in fragmented forest.
(This is what I really think, based on the concept of island biogeography - bigger areas have more species than smaller areas).
Prediction 2: There are more species in fragmented forest than in continuous forest.
(This is possible too, based on the intermediate disturbance hypothesis. Because fragmented forests may have greater variety in habitat types than continuous forest and species may be dispersing to or from fragments, there may be higher species richness in fragments if continuous forest is homogeneous with respect to habitat types and stable over time).
**After viewing the video, see the following caveat***
One note I would like to make is that I slightly disagree with the way the YouTube video frames their 'hypothesis'. The video states that the hypothesis is: "saltwater has lower freezing point than freshwater". That is a prediction, with a direction. The hypothesis should be something like: "There is a difference in the freezing point of saltwater and freshwater", with the predicted difference being that "saltwater has lower freezing point than freshwater". The null hypothesis would be that there is no difference in the freezing point of saltwater and freshwater, and you try to falsify the null by testing if there is a difference in freezing point between salt and freshwater. This is a subtle difference, but it means a lot when it comes time to do statistics.
Dear Students -
This week we'll be talking about one of my favorite topics in ecology - community ecology. Please watch this video and respond to the discussion topics below. While I am open to you working on just about anything for your independent research projects, I feel some of the most interesting questions have to do with community ecology - but I'm a little biased ;) We have data on multiple species co-occurring in the same habitat, where they are sharing/competing for space and resources. We also have data on multiple habitats where the numbers and kinds of species that co-occur vary. This is a great set-up to test, for example, how does the abundance or morphology of a species change in the presence or absence of a competitor? How does species richness vary with the abundance of resources? Which species tend to co-occur more frequently, and which tend not to co-occur? What do these patterns tell us about competition, co-evolution, and species interactions?
What defines an ecological community?
Give a few examples of communities.
What is the competitive exclusion principle?
What kinds of resources might be limiting, and which resources might not be limiting population size and competition?
What is an ecological niche?
What is the difference between a fundamental and a realized niche?
Describe MacArthur's research on warblers; what does MacArthur's work have to do with the theories of ecological communities?
What is character displacement?
Who are the Grants (Peter and Rosemary)? What are they famous for?
Describe the situation described for Darwin's finches - how did competition drive evolution?
What is mutualism?
What is commensalism?
How do these concepts relate to our studies of small mammals of Madagascar and bats of Belize? Please answer this question by coming up with a research question you might ask for your project about community ecology with our data. This should be something to do with how many species are in the communities, what traits they have, what resources they need, and how competition may relate to which species occur where.
This week we will be discussing an aspect of organismal biology that plays into it's population ecology intimately - life history. Please watch this video and respond to the discussion points below.
What is life history?
What is fecundity?
Compare and contrast the life histories of the three organisms discussed in this video.
Compare and contrast semelparity and iteroparity.
What is meant by 'fitness'?
We talk about the combinations of life cycle variables like fecundity, age of reproduction, and life span as 'life history strategies'. Discuss how natural selection may have lead to alternative life history strategies.
How do you think an organism's life history might be related to its population ecology? (Hint, think growth rates.)
How do you think life history variables relate to our projects on bats of Belize and small mammals of Madagascar?
Dear Students -
This week we'll take population ecology to a more complex level by examining the important dynamics of predator-prey relationships. Please watch this YouTube video and this one as well. Then respond to the following discussion topics.
What is co-evolution?
What is predation? Think broadly defined.
What are the types of predation?
What are some examples of adaptations predators have for capturing their prey?
What are some examples of adaptations prey have for avoiding being preyed upon?
What is aposematism? What are some examples?
What is mimicry?
The predator-prey dynamics of the lynx and the hare is one of the most classic examples of predator prey dynamics. Describe the relationship between the population sizes of predators and prey (the predator-prey cycle).
How might predator-prey dynamics fit into our studies of the bats of Belize and the small mammals of Madagascar?
Dear Students -
Great responses to last week's video and questions! This week we will continue exploring some of the basics of ecology, starting with the first level of complexity - the population. What regulates population size? In other words, what determines whether a population will increase or decrease over time? Please watch this Introduction to Population Regulation and respond to the following discussion topics. For this discussion, I also ask you to explore the topic a little more deeply, for example by reading up about population regulation here and doing some internet research on your own.
What are the two types of population regulation and what makes them different?
What is meant by logistic growth? What makes logistic growth different from exponential growth?
What is the term for the 'cap' on population size or the maximum population size?
What biological factors limit population growth rates?
What are some examples of factors that regulate populations that are not related to population size itself?
What did Thomas Malthus say about people?
How might these concepts be related to the research we're doing on small mammals of Madagascar and bats of Belize?
Please watch this Introduction to Ecology video and answer the following questions by adding Comments to this blog. Please answer by midnight Monday Oct 10. Enjoy!
What is Ecology?
What are biotic factors? Give an example of a biotic factor involved in the ecology of Central Park.
What are abiotic factors? Give an example of an abiotic factor involved in the ecology of Central Park.
What are the scales of study in ecology? List them at increasing levels of complexity.
Give an example of ways different biotic and abiotic factors in an ecosystem interact with each other. How might this apply in our projects about the bats of Belize and the small mammals of Madagascar?