1. Biodiversity, Species Interactions, and Population Control Chapter 5

2. Biodiversity, Species Interactions, and Population Control Chapter 5 Part 1: Species Interactions

3. Review!  What is evolution? Change in a species over time (many generations!)  What is natural selection? Pressures of environment ‘select’ genes that survive to produce more offspring  What is an adaptation? Trait that improves chances for survival and reproduction

4. Coevolution  The process by which two species evolve in response to changes in each other over time Sometimes organisms that are closely connected to one another by ecological interactions evolve together.

5. Coevolution: A Langohrfledermaus Bat Hunting a Moth

6. Species Interact in Five Major Ways  Interspecific Competition  Predation  Parasitism  Mutualism  Commensalism

7. Most Species Compete with One Another for Certain Resources  Competition When two species compete, their niches overlap  Competitive exclusion principle – no two species can occupy exactly the same ecological niche for very long Both species suffer harm Migration or predation will ultimately occur

8. Some Species Evolve Ways to Share Resources  Resource partitioning – species evolve to reduce niche overlap  Use shared resources at different Times Places Ways

9. Specialist Species of Honeycreepers

10. Sharing the Wealth: Resource Partitioning

11. 11 Predator or Prey?  Predation – act of one organism eating another organism Predator – organism that does the eating Prey – organism that gets eaten

12. Most Consumer Species Feed on Live Organisms of Other Species  Predators may capture prey by: Walking Swimming Flying Pursuit and ambush Camouflage Chemical warfare

13. Most Consumer Species Feed on Live Organisms of Other Species  Prey may avoid capture by Camouflage Chemical warfare Warning coloration Mimicry Deceptive looks Deceptive behavior

14. Important lesson to remember:  If an organism is small and beautiful… it is probably poisonous.  If it is strikingly beautiful and easy to catch…it is probably deadly.

15. Predation: Population Control  Cyclic fluctuations, boom-and-bust cycles Top-down population regulation Controlled by predation Bottom-up population regulation Controlled by scarcity of one or more resources

16. Your Turn!  Predator Prey Relationships

17. Video Clip  Orca Training Session 22:42 to 31:00

18. Mutualism: Clownfish & sea anemone  Both organisms derive mutual benefit  Intimate and obligatory  Neither can survive for long periods without the other

19. Mutualism: Oxpeckers Clean Rhinoceros; Anemones Protect and Feed Clownfish

20. Parasitism: Tapeworm and Humans  Parasite lives on or in the host and benefits at the expense of the host

21. Parasitism: Tree with Parasitic Mistletoe, Trout with Blood-Sucking Sea Lampreys

22. Commensalism: Flatworms and horseshoe crabs  Only one member benefits sharing space, defense, shelter, food  Flatworms that live on the gills of horseshoe crabs obtain food from the host, but do not negatively affect the host

23. Commensalism: Bromiliad Roots on Tree Trunk Without Harming Tree

24. Your Turn!  http://www.pbs.org/wnet/nature/lessons/symbioti c-strategies/video-segments/1496/ http://www.pbs.org/wnet/nature/lessons/symbioti c-strategies/video-segments/1496/ Ecological Relationships Predation Competition Commensalism Mutualism Parasitism

25. Biodiversity, Species Interactions, and Population Control Chapter 5 Part 2: Population Dynamics

26. Populations Have Certain Characteristics  Population dynamics – study of how characteristics of a population changes in response to changes in the environmental conditions  Populations differ in Distribution Numbers Age structure

27. Density Number of individuals of a population in a given area

28. Distribution Patterns Random Independent of other organisms No habitat preference

29. Distribution Patterns Uniform Even spacing Evidence for intra- specific competition (among other sea otters)

30. Distribution Patterns Clumped Organisms tend to be together Habitat preference Behavioral preference such as herding Most common!

31. Why clumping?  Species tend to cluster where resources are available  Protects some animals from predators  Packs allow some to get prey  Temporary groups for mating and caring for young

32. Populations Can Grow, Shrink, or Remain Stable  Population size governed by Births Deaths Immigration Emigration  Population change = (births + immigration) – (deaths + emigration)

33. Populations Can Grow, Shrink, or Remain Stable  Age structure – number of individuals in a given age class Pre-reproductive age Reproductive age Post-reproductive age

34. Density Dependent Limiting Factors Operates more strongly when a population is large and overcrowded Predation – more prey organisms – predator numbers will increase

35. Density Dependent Limiting Factors Parasitism – crowding helps parasites travel from one host to another Crowding – higher levels of stress (direct influence on immune system)

36. Density Dependent Limiting Factors  Competition Intraspecific – members of the SAME species compete Interspecific – competition between DIFFERENT species

37. Density-Independent Limiting Factors Will affect population regardless of its size Natural Disasters Forest fires Floods Earthquake Oil Spill

38. Genetic Diversity Can Affect the Size of Small Populations  Minimum viable population size – number of individuals endangered species need for long- term survival Founder effect Demographic bottleneck Genetic drift Inbreeding

39. Case Study: Exploding White-Tailed Deer Population in the U.S.  1900: deer habitat destruction and uncontrolled hunting  1920s–1930s: laws to protect the deer  Current population explosion for deer Lyme disease Deer-vehicle accidents Eating garden plants and shrubs  Ways to control the deer population