1 / 24

Ecosystems continually change over time

Ecosystems continually change over time . Chapter 3 – Science 10. Ecosystems continually change. 3.1 How Changes Occur Naturally in Ecosystems 3.2 How Humans I nfluence E cosystems 3.3 How Introduced Species Affect Ecosystems. Natural Selection.

austin
Download Presentation

Ecosystems continually change over time

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Ecosystems continually change over time Chapter 3 – Science 10

  2. Ecosystems continually change • 3.1 How Changes Occur Naturally in Ecosystems • 3.2 How Humans Influence Ecosystems • 3.3 How Introduced Species Affect Ecosystems

  3. Natural Selection • When an organism is born, it belongs to a species, but it also is born with unique characteristics. • Sometimes, these unique characteristics give organisms an advantage within their niche. For example, a salmon with a slightly larger tail may be able to swim a little faster or a little farther in a river. • Natural selection is the process where individuals with advantages are better able to reproduce and pass along their traits. • Those with unfavourable characteristics have less chance to reproduce and pass along their traits. • A salmon with a smaller tail may never have a chance to spawn because it cannot swim to the correct location. A salmon with a large tail may be able to swim faster and farther.

  4. 3.1 How changes occur naturally in ecosystems • Natural Selection • Change is possible in living things • Adaptive Radiation • Different species have “radiated” out from a common ancestor to inhabit different niches. • Lake Victoria Cichlid

  5. Cichlid – an example of adaptive radiation

  6. Galapagos Finches & Charles Darwin

  7. Natural Selection • Natural selection is the process that enables organisms to change in response to changes in abiotic and biotic components of an ecosystem.

  8. Adaptive Radiation • Adaptive radiation is the change from a common ancestor into a number of different species that can inhabit different niches.

  9. http://www.youtube.com/watch?v=AMtT5_AQmLg

  10. How ecosystems change over time: Ecological Succession • A connection with Chapter 12: Mt. St. Helens • http://www.youtube.com/watch?v=BaRAGzjSkzo

  11. Ecological Succession • Two types: • Primary Succession • Occurs in an area where NO SOIL exists • Slow • First organisms to appear are called pioneer species • Lichens, mosses etc… • Secondary Succession • After a disturbance in an area that already had soil and organisms • Fire, floods, building a road through a forest etc… • Much faster than primary succession

  12. Primary Succession: Mature Community • From Bare Rock to Mature Communities • A mature community is also called a climax community but a mature community is a preferred term because forests are constantly changing. • A forest is an example of a mature community.

  13. Primary Succession: Pioneer Species • Pioneer Species take advantage of bare rock. • Pioneer species decay and create soil. • Pioneer species provide food for other organisms, introducing new animals to the community. • New plants take over the new soil area until…. • The next species succeeds the previous species and so on until a mature community is established.

  14. Primary Succession: hundreds of years

  15. Secondary Succession: tens of years

  16. http://www.youtube.com/watch?v=V49IovRSJDs

  17. How natural events affect ecosystems • Natural events can change the abiotic and biotic conditions of an ecosystem • Some examples: • Flooding • Tsunamis • Drought • Insect infestations

  18. Flooding • Can cause soil erosion and wash away nutrients • Can cause the spread of disease in human populations • Bacteria and toxins polluting the water supply • Climate change • May be causing increase around the world

  19. Tsunamis • Huge rapidly moving ocean wave • Caused by earthquakes or underwater volcanic eruptions *Ch. 12/13 • Salt water kills the plants on shore *remember the NaCl lab?

  20. Drought • Below average precipitation • Crop failure, animal death • Made worse from climate change

  21. Insect Infestation • Insect infestations • Many insects play important roles in their ecosystems. • Even insects that appear destructive, such as the mountain pine beetle, actually play a role in the renewal of the forest. • The beetles have a symbiotic relationship with a species of fungus that inhibits the trees’ ability to use resin for protection. • However, when normal conditions are changed, infestations can occur. • Trees can be stressed from overcrowding drought or animal grazing and do not resist the insects as effectively. • A warmer climate and lack of forest fires allows the insects to spread much more effectively than in the past. • Not only are the trees affected, but so is the entire forest ecosystem, as well as any human industries relying on the forest. Mountain pine beetle.

  22. Insect Infestation • Mountain pine beetle example: • Forests are no longer exposed to sustained periods with temperature below -30°C • Climate change • Too many beetles attack stressed out trees. • A fungus symbiotic with the beetle is passed from tree to tree. • Blue stain fungus prevents the tree from making protective resin and destroys tissues • Trees die! • Many habitats are destroyed for organisms depending on the trees.

  23. Insect Infestation: Mountain Pine Beetle

  24. http://www.youtube.com/watch?v=anxJsQ7GEV4

More Related