1. Big Idea 2.D: Growth and dynamic homeostasis are influenced by changes in the environment Homeostasis in a Changing Environment

2. Essential Knowledge 2D1: All biological systems from cells to organisms to populations, communities, and ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy. 2D2: Homeostatic mechanisms reflect both common ancestry and divergence due to adaptation in different environments. 2D3: Biological systems are affected by disruptions to their dynamic homeostasis.

3. Organisms Respond to External Environments What was this called???

4. External Environment Made up of Biotic Things: Living

5. And Abiotic Things: Not Living External Environment

6. TPS: With your partner, make a list of 4 other biotic and 4 other abiotic factors that may affect organisms in an environment.

7. Case Study: Biofilms Bacterial cells attach to each other to form biofilms (a protective protein matrix cover) Communal group for protection and shared nutrients Grow with limited nutrients.

8. Cells Interact with Biotic/Abiotic Factors

9. Organisms Interact with Biotic/Abiotic Factors Organisms access to nutrients is affected by other factors i.e. symbiosis, predator-prey, nutrient availability etc

10. Interactions Among Organisms Symbiosis: relationship b/t 2 species Mutualism (+,+) Commensalism (+,0) Parasitism (+,-)

11. Mutualism Both Species Benefit Rhinos and oxpeckers

14. Commensalism One member is helped, the other neither benefits or is harmed Cows and Cattle Egrets

15. Parasitism + and - relationship parasite benefits, host loses parasite usually smaller than host Leech Bite, Thailand Lamprey

16. Ecosystems’ Stability is based upon interactions w/ biotic or abiotic factors

17. Evolution of Homeostatic Mechanisms Some mechanisms are conserved- showing common ancestry Others have changed, demonstrating divergent evolution (due to changing envs)

18. Case Study: Nitrogenous Waste Removal All animals produce N byproducts Animals in diff. envs. have evolved different mechanisms for excreting these wastes

19. Ammonia, NH 3 Toxic byproduct of protein degradation In dilute concentrations is no big deal, so aquatic orgs can excrete it into water

20. Urea Mammals convert NH 3 into urea  travels through blood to kidneys and is excreted w/ water and other substances as urine

21. Solid Uric Acid In birds and reptiles (and some desert mammals) N waste is excreted as a solid Prevents H 2 O loss and buildup of H 2 O waste in shell of an egg

22. Evolution of Circulatory System Shows Common Ancestry and Divergence

24. Disruptions at the Molecular/Cellular Level Affect Organisms Homeostasis Exs: viral infection of a cell, allergies, or dehydration in Willis’s body ;)

25. Disruptions to Ecosystems Affect Homeostasis Exs: food chain disruptions, natural disasters, salination (adding salt)