Presentation on theme: "Biodiversity What is it? Work with a partner to come up with a definition."— Presentation transcript:
Biodiversity What is it? Work with a partner to come up with a definition.
What is biodiversity? The total variation and richness found among all living organisms (plants, animals, fungi, microorganisms) We can talk about: – Genetic diversity – Species diversity – Functional diversity – Ecosystem diversity
Name as many organisms living in your backyard or schoolyard as you can. (use the notecard)
What do you think students answer to this question?
What do students think about biodiversity? Work in groups Sort the answers in order of increasing sophistication Fill out the first column of the worksheet: what characteristics are you using to sort the students’ answers into different levels? Write the letter of the student responses in the second column (teacher generated rubric); leave the last column blank for the “answers”
We asked 776 students (369 middle school, and 407 high school) in five states to name as many organisms as they could that lived in their backyard or schoolyard. The most common type of organism that students mentioned were vertebrates (birds, squirrels, dogs and cats), followed by invertebrates (most common answer: bugs!), and then plants. Very few students mentioned fungi or microbes; when they did, students simply said “microbes”. Additionally, it was much more common for students to provide the names of big groups of taxa such as “trees” or “bugs” rather than specifics like “sugar maple” or “ladybug”.
Implications… If you don’t know what lives here, how do you understand it? If you don’t understand that there are many different kinds of organisms within a big group like “trees”, and that those organisms have different functions and roles, why should you care if one kind of tree has a disease, or one kind of bug goes extinct? If all trees are the same, then you can’t understand the complexity within an ecosystem
Learning progressions are descriptions of increasingly sophisticated ways of thinking about a subject Knowledge, practice, discourse Goal: Create a grade 6-12 learning progression for biodiversity Anchored at the lower end by what we know about how younger students reason Anchored at upper end by what experts in the field believe students should understand when they graduate
Biodiversity & Student thinking: Students : Think that predator-prey relationships are the only things going on in an ecosystem (Magntorn & Hellden, 2007; Lock 1995; Munson, 1991) More easily connect biotic to biotic components than connect abiotic and biotic components (Lin and Hu 2003) and believe that if an animal’s main food source is taken away, it will die Tend to ignore processes and organisms that are not visible (Magntorn & Hellden, 2007) Think that balance (nature is constant and unchanging) is normal and returns after disturbance. (Sander, Jelemenska and Kattman 2006) View organisms as existing for the benefit of humans (Brumby, 1982) Tend to anthropomorphize organisms and actions in ecosystems
To help elementary students… Start with recognizing that there is more than one kind of: bugs, trees, plants, birds… Allow students time to explore the similarities and differences between organisms – ie make a tree key, observe insects, watch a bird feeder Discuss the “roles” of one group of organisms – how are different bugs different? Why are they different? Where does stuff “go” when it dies? - observe decomposition, discuss conservation of matter (carbon!) Combine biotic and abiotic – why did we find more x in this area? What is different between place y and z?
Allow time for exploration We will do several activities today that focus on collecting and identifying common organisms in a school garden You can use this as a starting point for exploring biodiversity in and of itself as well as the benefits of having a diverse organic garden as compared to a lawn with chemical inputs, etc
Who cares? Genetic diversity makes it more likely that a community can withstand changes A diversity of ecosystems provide “ecosystem services” – for free – such as water purification, climate regulation, pollination, intrinsic benefits
Shade Grown Coffee Increased bird, butterfly, and invertebrate diversity in shade grown coffee Fewer chemical inputs, less energy, less erosion Improved health for workers Organic coffee does NOT equal shade grown coffee
Who cares? Genetic diversity makes it more likely that a community can withstand changes A diversity of ecosystems provide “ecosystem services” – for free – such as water purification, climate regulation, pollination, intrinsic benefits Diverse communities may reduce your exposure to disease (dilution effect hypothesis)
What happens when you remove species from an ecosystem one by one? Keesing et al, Proceedings Roy Soc B, 2009
Are we at a tipping point? NOW: 43% of the earth’s surface has been converted to agriculture or urban systems, and much of the rest is crisscrossed with roads The last global-scale transition happened when 30% of the earth’s surface went from being covered by ice to being ice-free in approx. 3500 years
Barnosky, et al. 2012. Approaching a “state shift” in Earth’s biosphere. Nature.
Benefits of Organic Food Biodiversity is higher on organic farms Crops often do better because natural predators are left to eat the pests Less energy and fewer chemicals are used on organic fields Some evidence that organic foods are better for you *
Is the world really “hungry”…? Currently, world agriculture produces 17% more calories per person today than it did 30 years ago, despite a 70% population increase There is currently enough food in the world to provide everyone with at least 2,720 calories per day Close to 1 billion people are considered “hungry”, or malnourished; most of those are in Asia and Africa More than 1/3 of the adult population of the US is obese; almost half of the student body in Poughkeepsie qualifies as overweight or obese (2009 data) We waste 30-40% of our food globally
What you can do: Buy local, buy organic, ask questions
Measuring Biodiversity Species richness: number of different species in a given area; “the number of different species in a community” Species evenness: how equal the community is; “the relative abundance of individuals within each of those species” Abundance: how many Composition of a community – who lives here? What are their roles? What are the implications (ie water quality, “health” of a community)? Diversity indices include richness and evenness: – Shannon index (also called Shannon-Weaver or Shannon- Weiner); Simpsons index; Gini Index; many others!
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