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Biodiversity, Species Interactions, and Population Control Chapter 5.

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Presentation on theme: "Biodiversity, Species Interactions, and Population Control Chapter 5."— Presentation transcript:

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!  c-strategies/video-segments/1496/ 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


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