1. Sustaining Ecosystems and Human Activity
Understanding Ecosystems

2. Ecology:
the study of the interaction of living things with each other and with the non-living factors in the environment

3. Sometimes these interactions are disrupted by the introduction (either accidentally or deliberately) of an Invasive Species – a species that is not native to an area. For example: The Round Goby
fish that is not native to the Great Lakes
appeared in 1990’s
brought over accidentally by ships from Europe
no natural predators
lay many eggs, twice a year

4. aggressively defend spawning areas
greedy bottom feeders
less food for other species

5. Another Species to Watch: The Disappearing Frog
the frog population has been in a steady decline recently
the frog is considered to be an indicator species
It gives an idea of the general health of the ecosystem

6. The following could be causes of a declining frog population:
Decline
loss of
habitat
climate
change UV
radiation
pollution

7. Life on Earth
A habitat is the place where an organism lives. It includes the space as well as the other organisms
Terrestrial habitats exist on land, while aquatic habitats are found in the water.
the earth is surrounded by a thin layer of gas called the atmosphere.

8. this gas layer keeps the Earth’s temperature just right
contains O2, CO2, N2 and water vapour for living things
blocks out harmful solar radiation

9. the water on the planet Earth is called the hydrosphere
the solid part of the Earth is called the lithosphere
The biosphere is all of the places on the planet where life can exist

10. Introducing Ecosystems
An ecosystem is all the living and non-living things in a particular area
the living part an ecosystem is the biotic component (wasps, perch, pine trees, microorganisms and fungi)
the non-living part is called the abiotic component (water, rocks, air and weather)

11. the biotic and abiotic components are all related
when a component is changed, everything can be affected (Ex: Round Goby)
Ecosystems can be as large as an entire forest or as small as a rotting log

12. members of the same species living in an ecosystem are called a population (all of the white-tailed deer in Short Hills Provincial Park)
a species is a group of organisms that can naturally reproduce together
all of the populations of different species form a community (all of the different species living in Short Hills Provincial Park)

13. Sustainability

14. most natural ecosystems are sustainable
a sustainable ecosystem is one that survives and works well over time
natural ecosystems occur where there is little influence from man
man-made ecosystems, such as parks, are protected and maintained by humans

15. The Case of Easter Island
Is thought to have once been a thriving island
People built statues and lived in forested area
People cut down trees to grow crops, to burn as a heat source, until there were no more trees
This lead to erosion, loss of plants as a food source, no extra materials to make houses, boats
The island could no longer support the human population and society began to die off
Only the statues remain

18. human actions such as cutting down trees, oil spills and the planting of different plant species can change an ecosystem
natural events, such as forest fires and floods can also change an ecosystem
ecosystems supply resources for humans (lumber, medicine, seafood)

19. these resources need to be managed so that they are sustainable
natural ecosystems are also used for recreation
“take only pictures” and “leave only footprints”
even the footprints can be a problem!

20. Interactions in the Ecosystem

21. every species interacts with its environment
these interactions are referred to as the species ecological niche
niche includes what a species eats, what eats it, where it lives and how it behaves

22. There are different types of consumers:
herbivore (eat producers/plants)
carnivore (eats consumers/animals)
omnivore (eats producers & consumers)
scavenger/decomposer (feeds on dead or decaying organisms)

23. consumers that eat plants are also called primary consumers
secondary consumers such as carnivores, eat other consumers
a consumer that eats a secondary consumer is called a tertiary consumer

24. the transfer of energy from the sun to a producer, primary consumer, secondary consumer and so on is called a food chain

25. quaternary
consumer
top
carnivore
Hawk
tertiary
consumer
Snake
carnivore
secondary
consumer
carnivore or
omnivore
Frog
primary
consumer
Grasshopper
herbivore
producer
Grass

27. ENERGY FLOW IN THE FOOD CHAIN
each level of production or consumption in the food chain is called a trophic level
the arrows in a food chain represent energy transfer
most of this energy is used for life functions or lost as heat
only a fraction of the energy transferred to an organism is passed on to the next level

28. Food Chain Pyramids food chains can also be illustrated using pyramids
There are 3 main types:

29. Shows the population of each level in a food chain.
i) Pyramid of Numbers
Shows the population of each level in a food chain.

30. - shows the dry mass of each trophic level
ii) Pyramid of Biomass
- shows the dry mass of each trophic level

31. iii) Pyramid of Energy Shows the energy of each trophic level
- Most useful of the pyramids

32. real feeding relationships are more complex
most consumers have more than one source of food
several food chains interconnected form a food web

33. Black
Bear
Cougar
Deer
Hawk
Chipmunk
Grouse
Groundhog
Berries
Grass
Seeds
Robin

35. Energy Flow in Ecosystems

36. Radiant energy from the sun supports life on Earth
Only about 0.025% is absorbed by plants for this purpose
the remainder is absorbed (70%) or reflected (30%)

37. Sun provides energy for photosynthesis
Produces food (glucose) and oxygen
Plants are called producers because they make their own food
light energy
carbon water glucose + oxygen
dioxide
chlorophyll

38. energy is stored in glucose
plants use much of this energy for themselves
producers release oxygen during this process of photosynthesis

39. the energy that is not used can be passed on to other organisms that cannot make their own glucose
recall that organisms that cannot make their own food are called consumers
when consumers eat food, the energy is released through cellular respiration

40. glucose + oxygen carbon + water + energy
dioxide
photosynthesis and respiration are complementary processes
the reactants of one are the products of the other

41. Biotic Interactions
The interaction between members of two different species that live together in a close association. You may not see any interaction from the surface.between the sea anemone and the clown fish. The clown fish eats animals that are attracted to the sea anemone and the fecal matter from the fish feeds the sea anemone
There are three main types of symbiotic relationships:
1. Mutualism- both organisms benefit from the relationship ex. Oxpecker and zebra
2. Commensalism- one organism benefits while the other is unaffected ex. barnacles
3. Parasitism- one organism benefits at the cost of the host ex. fleas

42. Predation When one organism consumes another organism for food
The consumed organism is called prey and is eaten by the predator
This lady bug is the predator for aphids (a bug that destroys many crops).
                                 

43. Competition
Occurs when two or more organisms compete for the same resource such as food in the same location at the same time.
Dandelions compete with the grass for same resources; water, nutrients and light
2 TYPES:
Interspecific Competition – competition between different species ex. Cat and hawk for a mouse
Intraspecific Competition – competition within the same species ex. 2 cats for a mouse