1. Biotic Relationships

2. How do Biotic Factors affect other Biotic Factors?
Types of Interactions...

3. Symbiotic Relationship (or Symbiosis)
refers to the interaction between members of two different species that live together in close association
Can be Positive or Negative

4. Commensalism
One species benefits and the other species is neither helped or harmed.
Host species may provide shelter or transportation for the others species.

5. Mutualism Both organisms benefit Eg flowers and bees
Acacia Tree and Ants video

6. Eg. Lichen is algae and fungus
Over 2500 types of lichens exist and are found in every biome on Earth
Each lichen consists of an alga and a fungus
Alga produces sugars and oxygen for the fungus through photosynthesis
In return the fungus provide carbon dioxide, water, minerals, and protection from dehydration for the alga.

7. Parasitism
One species benefits and another is harmed

8. Competition
harmful interaction between two or more organisms within the same niche, causing them to compete for the same resource in the same location a the same time. 
Resources include: food, water, sunlight, habitat
Some plants have characteristics that make them successful competitors. 
Eg. Spotted knapweed releases chemical into the soil, which prevents the growth of other plants and allow the knap weed to populate a field quickly.
Same niche
Produces seeds from one plant. One of th eworst rangeland weeds in BC
Coyotes and wolves may compete for food

9. Resources to compete for:
food, water, sunlight, or habitat.

10. Competition Lions and Hyenas compete for similar food and space.
Plants compete for sunlight.
Produces seeds from one plant. One of th eworst rangeland weeds in BC
Coyotes and wolves may compete for food

11. Lemming Population Explosion

12. Predation
One organism benefits (predator) while the other (prey) is harmed (eaten).
Predators have adaptation's that make them effective predators
Eg. Keen sense of smell,
Eg. sharp, pointed teeth

13. Prey have adaptations Protection, Camouflage, Mimicry
Vicery butterfly looks like the bitter-tasting monach butterfly, Eg turtles and clams have hard shells

14. Predator-Prey Relationships
The size of a prey population can be affected by the number of predators
Eg. Lynx and Hare populations

15. Niche - organism’s role in the ecosystem

16. Niche
Because of their long legs, great blue herons can find food in deeper water, which allows them to occupy a niche that other heron species with shorter legs cannot.

17. Human Impact: Introduced Species

18. How Introduced Species Affect Ecosystems
Native species are plants and animals that naturally inhabit an area.
Because of the immigration to North America by many people from other continents over the past 400 years, many new species have been introduced.
These new species of plants and animals are called introduced species, foreign species, non-native species, exotic species, or alien species.
Many of these species are harmless or sometimes even beneficial.
An invasive species, such as purple loosestrife, negatively affects native species and often reduces biodiversity as a result.
European leaf-feeding beetle, and the purple loosestrife.

19. Impact of Invasive Species
Invasive species often take advantage of their new habitat.
They may have no predators, are aggressive competitors, and reproduce quickly.
While the native species have an established balance, the invasive species can throw off this balance.

20. Competition Atlantic Salmon escape farm fish pens.
Grow faster, live longer

21. Predation
Sea lampreys invaded the Great Lakes in the early 20th century through shipping canals.
Sea lampreys are so destructive that, under some conditions, only one out of seven fish attacked will survive.
Sea lampreys prey on all types of large fish, such as lake trout, salmon, rainbow trout (steelhead), brown trout, whitefish, yellow perch, burbot, walleye, and catfish.
(c) McGraw Hill Ryerson 2007

22. Koi Karp

23. Disease and parasitism
EG. West Nile virus is a mosquito-borne flavivirus native to Africa, Europe, and Western Asia.
WNV causes severe disease humans, horses and other vertebrates. 
(c) McGraw Hill Ryerson 2007

24. Parasitism: Sea Lice and Fish Farms

25. Habitat alteration
Some invasive species can change the physical structure of the ecosystem by digging, burrowing, blocking sunlight, or changing the chemistry of the ecosystem.
(c) McGraw Hill Ryerson 2007

26. Invasive Species in British Columbia
Eurasion Milfoil
Norway rat
See page 142
(c) McGraw Hill Ryerson 2007
American Bullfrog
European Starling

27. Check your Understanding
What is symbiosis?
What is commensalism
Give an example of mutualism
Give an example of parasitism
What resources do organism compete for?
What is predation?
Provide one example of a predator.
State two ways in which prey avoid predators.
What is a niche?

28. Predator Prey Activity

29. Saving an Ecosystem Under Siege
It often takes human intervention to save established ecosystems.
The Garry Oak Ecosystem Recovery Team (GOERT) is trying to save several areas of the Garry oak ecosystem in British Columbia.
95 percent of the original ecosystem has been lost to urban development, and the remaining 5 percent is threatened by invasive species.
Garry oak trees are a keystone species.
Scotch broom, English ivy, and other
plant species are its biggest threats.
GOERT has representatives from many groups including the British Columbia government, First Nations, conservationists, scientists, and businesses.
Garry oak forests may be better suited to survive in
the future than Douglas fir forests.
Garry oak ecosystem
See page 143
(c) McGraw Hill Ryerson 2007
Take the Section 3.3 Quiz