CORE: pck

Biology Education EDF4402 Pauline Steele 11967048

VCE YEAR LEVEL
Year 11; Unit 2
Organisms & their environment.
Area of Study 2:
Dynamic Ecosystems /
IMPORTANT BIOLOGY CONCEPT: Ecological Systems
Big Idea: Ecosystems are made up of many components.
What you intend the students to learn about this idea. / An ecosystem is defined as an arrangement of living organisms interacting with each other and with the physical surroundings occupying a given area.
Interaction between non-living (abiotic) and living (biotic) elements. Abiotic factors include range, quantity & distribution of light intensity, water, wind speed, aspect, slope of land, salinity, nutrients, pH and moisture in soil, temperature, solar radiation, atmosphere (oxygen level, air pressure).
Biotic factors include composition of species, numbers & distribution of plants, animals & microorganisms. Also, disease, parasitism & predation.
Different types of ecosystems: terrestrial - desert, alpine, rainforest, tundra, savanna grassland, taiga; aquatic – freshwater (river, pond, swamp) or marine (ocean, mangroves).
Ecosystems may be named according to their abiotic environment (lake, rock pool), or based on the dominant organism of the community (oyster community, eucalyptus forest) or based on the structure of the plant community (woodland, open-forest). A biome is a general category of ecosystem defined on the basis of climate (desert, rainforest) or specific characteristics (coral reef).
When discussing dynamic ecosystems many levels of organisation may be observed.
The surface of the earth, the biosphere, is composed of many ecosystems.
A population is a group of organisms from one species living in the same area.
A community is an ecological grouping of all the different populations (animal & plant) that live together and interact within the ecosystem. The richness of a community depends on the type of habitat. A habitat is the physical location where the community of organisms live.
A microhabitat is a local smaller area within a habitat.
An ecological niche is the role that a particular species occupies in an ecosystem eg. plants have the role of "producers" of energy.
An ecosystem is an integrated whole of interdependent parts that function as a unit. Eg. A tundra ecosystem consists of its abiotic environment, producers, consumers & decomposers.
Why it is important for students to know this. / Appreciation for the complexity & interaction between living & non-living elements will enhance understanding of the significance of all components within an ecosystem.
Because human intervention (damming a waterway) or natural disturbance (cliff erosion) causing changes to the abiotic environment may not seemingly affect the living communities of an ecosystem but actually can upset the delicate balance of a self-sustaining ecosystem, determining its success or failure.
What else you know about this idea (that you do not intend students to know yet). / As well as having natural ecosystems there are artificial or man-made ecosystems. These are maintained & manipulated by man. Examples include sugarcane fields, aquariums, dams, gardens & orchards.
This big idea leads into interactions between species (eg. symbiotic relationships) and also closely ties with food webs (cycling of matter & bioaccumulation) and later population dynamics.
Knowledge about students’ thinking
/difficulties connected with teaching this idea. / Initially, students may consider environment and ecosystem to have interchangeable meanings and so it is imperative that students can clearly define the organisational terms related to the structure and function of an ecosystem.
Students may only link interactions within an ecosystem between animals and plants (biotic elements) and may not realise the existence of interactions with abiotic elements.
Teaching procedures
(and particular reasons for using these to engage with this idea). / Brainstorm list of words relevant to the topic of ecosystems from prior knowledge, reading and through class discussion. Form a class consensus on the meaning of each list word offered. Ask each student in the class to volunteer an abiotic factor and ask classmates for approval of their idea.
Students draw Venn diagrams representing how the terms regarding ecological groupings and components (species, population, community, ecosystem, habitat, microhabitat, niche, biosphere, biotic and abiotic) fit together.
From the class-suggested list of ecosystems, students are to select an ecosystem, describe it, note its potential abiotic factors and list some expected organisms and their niches that one would find in this ecosystem. Some research may be required.
Students to annotate diagram of “Stratification of a tropical rainforest” whereby the vertical layers of this habitat are divided into microhabitats receiving a differing range of abiotic and biotic factors.
Field trip of an ecosystem whereby an investigation of interactions between biotic and abiotic factors can occur.
Specific ways of ascertaining students’ understanding or confusion around this idea
(include likely range of responses). / Students work in pairs to create a relationship web with link-lines, using the selected ecosystem and information, as above, that builds a picture of the interactions that exist in the ecosystem.
“What if” Questions:
Teacher-generated “what if” questions to probe understanding. For example, how might a change of an abiotic element affect or influence the organisation of an ecosystem? Give an example.
Class discussion as to why an ecosystem is described as “finely balanced”; teacher listens to students’ explanations.

References

Victorian Curriculum Assessment Authority (VCAA) VCE Biology web page at

http://www.vcaa.vic.edu.au/vce/studies/biology/biologyindex.html

Kinnear, J. & Martin, M. (2006). Chapter 13: Ecosystems and their living communities. In Nature of Biology Book 1 (3rd ed.). Jacaranda. ISBN:9780731402366

http://www.hi.com.au/biolVic/pdf/Biology1SWa.pdf

Sanders, Y. Heinemann Biology 1: Student Workbook (4th ed.).Pearson Secondary. ISBN: 978 1 74081 499 7

http://www.biozone.co.nz/modular.php

Biozone International, Ecology –Biology Modular Workbook Series. ISBN:1-877329-86-X

http://www.microbiologyprocedure.com/microbial-ecology-of-different-ecosystems/types-of-ecosystems.html

1