Species, communities and ecosystems

In this section (IB Topic 4.1)

- Species

- Communities

- Energy and modes of nutrition

- Nutrient flow (see Sealed Mesocosm Project)

Vocabulary and cross-word

4.1_Vocabulary.pdf

Down

1 experimental tool environmental controlled conditions

3 organism that manufactures its own food

4 obtain nutrients by external digestion

6 non-living factors in an environment

9 organisms that can interbreed and produce fertile offspring

Across

2 Autotrophs are fed on by ------- consumers

5 ----------- sampling method used to study vegetation

7 obtain nutrients from dead organisms by internal digestion

8 heterotrophs that feed on living organisms by ingestion

10 organisms of same species living in the same area at the same time

11 populations of different species living together and interacting

Species

There are 41 different species of birds of paradise in Papua New Guinea. Hybrids are rarely produced, so species remain distinct. Species interbreeding produce offspring. Cross-breeding often lead to infertile organisms. Watch this video... Why do you think is the reason for such an elaborated ritual of courtesy?

Testing for association between two species

The chi-squared test is an statistical analysis that ca be used to test whether two species are or not associated in a specific location/ecosystem. Data from the distribution of species can be collected by quadrat sampling.

The null hypothesis is that there is no pattern in the presence of the two species: if one is present, it is random whether the other is there or not. The alternate hypothesis is that there is a pattern when it comes to the presence of the two species. There are two possible interactions that could lead to this pattern: one species could be present to the exclusion of the other or one species could encourage the presence of the other; i.e., the presence of one is associated with the presence of the other or the absence of one is associated with the presence of the other.

Moss and heather

For example moss and heather occur together. If enough data from the distribution of these two species is collected from a natural ecosystem (not artificially maintained by humans) and a chi-squared test is conducted, the result would be lead to rejection of the null hypothesis. The conclusion should be that the presence of the two species is not random. Alternatively, the presence of one species of the algae Fucus is associated with the absence of the other.

Simple explanation of how to use the p-value to draw conclusions from statistical output. It includes the story of Helen, making sure that the choconutties she sells have sufficient peanuts.

This is a relatively straightforward explanation of most of the principles of the chi-squared test, though it doesn’t go into the test of association as clearly .

Virtual Lab 1: Organisms in biomes and ecosystems

Explore different biomes and ecosystems and identify the organisms living in each environment.

In this interactive ecosystem simulation, you can answer questions about individual organisms from different biomes and the ways in which they interact with their environment (here).

Communities

Activity - Stocks and flows diagrams

Use concept mapping strategies and mapping software such as Bubbl.us to represent stocks (shown as boxes) and flows (shown as arrows) of energy and nutrients within an ecosystem. Population would be the stock (shown as boxes) and the immigration, births are inflow and the outflow would be deaths and emigration. What factors influence the inflow? And what factors influence (increase/decrease) the outflow?

Virtual Lab 2 Marine Biome

Use this simulation to set up a marine community system. Then alter the variables and observe the outcomes. Draw conclusions based on you observations and take notes to contrast with other examples of communities that you find in your textbook and in class activities (here).

Virtual Lab 3 Abiotic and biotic factors

In this Virtual Lab, you will observe how temperature affects a fish's metabolism. One way to determine the metabolic rate of a fish is to observe the rate of water movement over the gills. Rapid movement of the operculum, the bony covering over the gills, indicates increased consumption of oxygen, while slow movement indicates decreased consumption. Counting the number of movements can give observers an indication of a fish's metabolic rate (here).

How do organisms react to changes in abiotic factors? To survive, living things must adapt to nonliving factors in the environment. These nonliving, physical factors, including temperature, climate, air, water, sunlight, and soil, are called abiotic factors. Abiotic factors determine the kind of organisms that are able to live in a certain environment.

Crash Course Ecology #4. Explains how the interactions between species are what define ecological communities, and community ecology studies these interactions anywhere they take place

Paul Andersen explains the major classification terms in ecology and how a community can be measured by species composition and species diversity. The symbiosis of leaf cutter ants is included. The video ends with a discussion of population growth.

Energy and modes of nutrition

Food webs

This interactive website allows you to make food webs. A food chain shows how each living thing gets its food. Some animals eat plants and some animals eat other animals. For example, a simple food chain links the trees and shrubs, the giraffes (that eat trees & shrubs), and the lions (that eat the giraffes). Each link in this chain is food for the next link. A food chain always starts with plant life and ends with an animal.

Video explaining how fungi are understood as nutrients to the human consciousness and ecological sustainability (2 min 30)

Short video summarizing the main role of decomposers (3 min)

The Elephant: life after death. Fascinating 2-minute video showing what happens when an elephant dies in the wild and the life cycle that it feeds, from vultures and leopards to flies and beetles.

Here's a powerful provocation from artist Jae Rhim Lee. Can we commit our bodies to a cleaner, greener Earth, even after death? Naturally, using a special burial suit seeded with pollution-gobbling mushrooms. Yes, this just might be the strangest TEDTalk you'll ever see!

Helmont's experiment

Helmont's experiment and the willow tree

Discuss von Helmont’s experiment to explore misconceptions regarding the origins of plant biomass.

In 1634, Jan Baptist van Helmont was arrested for the crime of studying plants and other phenomena. While under house arrest, he started to consider how plants grew. The prevailing theory at the time was that plants grew by eating soil, and van Helmont devised a clever investigation to test this idea. He weighed a willow tree and weighed dry soil. He planted the tree, watered it and then left it for 5 years. He then re-weighed the tree, which had increased in mass by over 12 stone. He dried the soil and weighed it, showing that the soil was almost the same mass. He concluded that the tree grew by drinking water.

Other stuff

These series of lectures on Species and speciation from the Open Yale Courses are a great complement to further understanding ecology and evolution.

Play with this, it's really really cool.

Report abuse