Biophysical Interactions

Let's start with a Kahoot pretest on Ecosystems at Risk.

Work through the following slides below on what an ecosystem is, and how it functions. Answer each question in full sentences in your workbooks.

Remember your notes are revision!

Ecosystems at risk biophysical interactions updated.ppt

Biophysical Interactions

An ecosystem is the dynamic complex of plant, animal and microorganism communities and their non-living environment as a functional unit. Ecosystems include the biotic (living) and abiotic (non-living) elements of the environment and the relationships between the components.

• Each ecosystem has its own specific plant and animal community

• Plants and animals are related to each other through relationships within food chains and food webs

• Nutrients are retained and recycled by living things within ecosystems

• The two main types of ecosystems are:

– Terrestrial ecosystems or biomes (land-based ecosystems) e.g., forest, grasslands, deserts

– Aquatic ecosystems (water-based ecosystems) e.g., ponds, lakes, rivers, oceans, coral reefs, estuaries and coastal and inland wetlands

Productivity of ecosystems

For an ecosystem to be functioning at its most productive level. The natural processes which occur within ecosystems must be occurring as close as possible to their natural state. The most important processes of ecosystems are:

– The Carbon Cycle

– The Nitrogen and Phosphorous Cycle

– The Nutrient Cycle

– The Oxygen Cycle

The Nutrient Cycle

Biomass is a measure of the mass of all organisms at a particular trophic level. A biomass pyramid shows the total weight (biomass) of organisms at each level for a particular habitat. Note: if the biomass pyramid exists in an ecosystem in this form than the ecosystem is in equilibrium.

A food chain is a series of organisms, each eating or decomposing the preceding one. However, in nature the feeding relationships of living things are much more complicated than simple food chains. A sometimes-complicated branching diagram which shows the feeding relationships of all living things in an ecosystem or particular area is called a food web. Energy is transferred from one animal to another through food chains and food webs.

• Every food chain begins with a producer organism

• Energy flows in the direction of the arrows

• Some energy is lost at each step in the food chain as heat

• The source of energy is the sun

Trophic levels: The feeding level of an organism is its trophic level.

A simplified ecosystem is made up of:

• Tertiary Trophic level – Decomposers: organisms that feed by breaking down the dead organic matter in an ecosystem (e.g. fungi, bacteria)

• Secondary Trophic level – Consumers (most animals): organisms that are unable to produce their own food, and consume plants and animals to obtain energy

• Primary Trophic level – Producers (plants): autotrophic organisms, they convert sunlight into energy through photosynthesis

Biomass: Biomass is a measure of the mass of all organisms at a particular trophic level. A biomass pyramid shows the total weight (biomass) of organisms at each level for a particular habitat. Note: if the biomass pyramid exists in an ecosystem in this form than the ecosystem is in equilibrium.

Productivity: Productivity is the rate at which biological matter (biomass) is produced by an ecosystem or part of an ecosystem. The more productive the ecosystem, the healthier it is.

Energy: Energy in a food chain declines the further up the food chain you go. For example, a producer has more usable energy than a tertiary consumer. This is because energy is lost by organisms through activity and also through heat.

Photosynthesis: Plants make food in their leaves, which contain a special green pigment, or colouring, called chlorophyll. The chlorophyll uses energy absorbed from sunlight to convert carbon dioxide from the air, and water from the ground, into a sugary form called glucose.

Lesson 2

What leads to a diverse Ecosystem?

Ecosystems can be thought of as a set of interactions between the biotic and abiotic features. The biophysical Interaction model uses the interactions between the Atmosphere, Lithosphere, Hydrosphere and Biosphere to describe as ecosystem. When an ecosystem is described in this way, then an alteration (either human or natural) will alter the ecosystem. For example, if the amount of precipitation were increased due to climate change, then there may be more erosion of top soil leading to reduced fertility and an altered biosphere (Queensland Government, 2015).

The variations in sunlight and heat, available water and available nutrients determine how quickly an ecosystem can grow which in turn affects how lush or dense an ecosystem's vegetation appears. The variations in these factors alter from location to location changing the abiotic character and producing different ecosystems. For this reason, the same biome may produce quite different ecosystems at two different locations.

Insolation, altitude, aspect, parent material, ocean and atmospheric circulation patterns are all highly variable and have significant impacts on the biophysical environment.

Task 1 - Glossary of Key words

Using your textbook and extend research, create a glossary of key terms and definitions in your workbooks.

Insolation
Altitude
Aspect
Parent Material
Ocean and atmospheric circulation patterns

Task 2 -

Analyse the map above, what observations can be made about ecosystems and geographical location? Write your response in your workbook.

Task 3 - Biodiversity Cloze Passage

Word Bank

survival species ecological levels

animals biotic function robust

species diminished processes trophic

___________________________________________________________________________________________________________________________________________

Biodiversity is usually considered at three ………………….: genetic diversity, …………………. diversity, and ecosystem diversity.

Genetic diversity:

Genetic diversity is the variety of genetic information contained in all the individual plants, …………………. and micro-organisms. Genetic diversity occurs within and between populations of species as well as between ………………….. Genetic diversity favours the …………………. of a species, because it increases the chances that some members of the species will have characteristics that aid their survival if the population is subject to stress.

Species diversity:

Species diversity is a measure of the number of species at each …………………. level of an ecosystem. In simple terms, the greater the species diversity the more …………………. the ecosystem: if the population of one producer or consumer organism crashes there are other producers or consumers available that can fulfil a similar …………………. in the ecosystem. When ecosystems are diverse, there is a range of pathways for the …………………. processes, such as nutrient cycling. If one pathway is damaged or destroyed, an alternative may be used and the ecosystem can continue to function at its normal level. If the level of biodiversity is …………………., the functioning of the ecosystem is put at risk.

Ecosystem diversity:

Ecosystem diversity is the variety of habitats, …………………. communities and ecological …………………., as well as the diversity present within ecosystems in terms of habitat differences and the variety of ecological processes.

CHALLENGE - answer this question - how do wolves change rivers?

You have three minutes to come up with a plausible explanation of how on earth wolves might change rivers!

Energy Cycling and Food Chains

All ecosystems cycle nutrient and energy through their food chains. For nearly all ecosystems, energy is taken from the sun and converted to sugars and proteins by autotrophs (producers). These sugars and proteins are eaten by heterotrophs (consumers). When plants and animals die they are broken down by decomposers. Energy is lost as heath, movement and waste at each trophic level and so there is less biomass at each higher level. This is why there are fewer apex predators, such as lions than secondary consumers, such as zebras.

The removal of a species or trophic level can cause disruption in ecosystems, sometimes referred to as a trophic cascade. The best example of this has been the removal and reintroduction of wolves in Yellowstone National Park.

Task 4

Answer the following question using a TEEL paragraph structure, in your books:

Using an example, explain how the removal of a species might transform an environment.

Page updated

Report abuse