For an ecosystem to be healthy, every animal needs to interact with biotic and abiotic factors equally. If for some reason one of those organisms is taken out of the equation, we can see by the above food web how that would affect other living organisms in that ecosystem. In an ideal ecosystem, each trophic level is allowed to prey on each other equally, however in reality, due to human activity that is not always the case.

Humans are constantly taking organisms out of ecosystems. Deforestation and fishing are just two examples where we do it directly.  


© elasmo holdings pty ltd

© elasmo holdings pty ltd

Using the above food web, choose a species you’d like to focus on.

How would the food web be affected if your species was removed?

The role of Phytoplankton

We have already learnt that Phytoplankton are microscopic, plant-like organisms that grow abundantly in the seas and oceans. Much like land-based plants, phytoplankton require sunlight, water and nutrients for growth. They get their green colour from chlorophyll which also allows them to perform photosynthesis, creating their own food from sunlight and carbon dioxide. They provide us with 70% of the Oxygen we breathe and make up the base of most marine ecosystems.



Discuss how introducing a new species into an ecosystem could impact on food webs?

Can you think of other examples from history?


In 1914 the culling of wolves, prairie dogs, and other animals injurious to agri-culture and humans began. By 1926 the last two wolves were killed.


Ecology is the branch of biology which studies the interactions among organisms and their environment.

By studying individual ecosystems and the interactions within them, we can make more informed decisions about what happens when we cut a lot of trees down to make way for new houses or what happens when we take too many fish. Understanding how far spread these interactions are is key to understanding what other species may be affected.

Living things and the environment


Do livings things rely on their environment? Can you explain your answer?

All living things require

  • Air to breathe

  • Water to stay hydrated

  • Food to provide energy

  • Sunlight for energy

  • Suitable and safe environment to grow and reproduce.

Now we understand the interactions and interdependence of living things. Remember that 70% of the Earth’s surface is water and the ocean produces 70% off the oxygen we need to breathe.

What does all this have in common?

Unity - everything is connected.

Our individual health and the health of all species will always correlate to the health of the planet. Perhaps, in this connectivity we can find compassion, empathy - finding the wisdom to live in harmony with one another.

© elasmo holdings pty ltd

© elasmo holdings pty ltd