Understanding Reproductive Strategies and Interactions in Population and Community Ecology

1. Chapter 6 Population and Community Ecology

2. Reproductive Strategies • K-selected species- the population of a species that grows slowly until it reaches the carrying capacity. Ex. elephants, whales, and humans. • r-selected species- the population of a species that grows quickly and is often followed by overshoots and die-offs. Ex. mosquitoes and dandelions

4. Survivorship Curves

5. Species Distribution • Related to THREE things: • Fundamental Niche abiotic conditions that it can tolerate • Ability to disperse to a new area • Interactions with other species (symbiosis)

6. Competition • Interaction among organisms that vie for the same resource in an ecosystem • Intraspecific • Competition between individuals in a population • Interspecific • Competition between individuals in 2 different species

7. Limiting Resources • Any environmental resource that, because it is scarce or at unfavorable levels, restricts the ecological niche of an organism

8. Ecological Niche • The totality of an organisms adaptations, its use of resources, and the lifestyle to which it is fitted • Takes into account all aspect of an organisms existence • Physical, chemical, biological factors needed to survive • Habitat • Abiotic components of the environment • Ex: Light, temperature, moisture

9. Ecological Niche • Fundamental niche • Potential idealized ecological niche • Realized niche • The actual niche the organism occupies • Ex: Green Anole and Brown Anole

10. Ecological Niche • Green Anole and Brown Anole • Fundamental niches of 2 lizards initially overlapped • Brown anole eventually out-competed the green anole- reduced the green anole’s realized niche

11. Gause’s Law of Competitive Exclusion • If two similar species occupy similar niches, one will outcompete the other. • One species excludes another from a portion of the same niche as a result of competition for resources 11

12. Interspecific Competition

13. Resource Partitioning

14. Resource Partitioning (fig 6.16) • Temporal Resource Partitioning (Wolves/Coyotes) • Spatial Resource Partitioning (plants/birds) • Morphological Resource Partitioning (Darwin’s Finches)

15. Spatial Resource Partitioning • Resource Partitioning • Coexisting species’ niche differ from each other in some way

16. Interactions Among Organisms • Symbiosis • An intimate relationship between members of 2 or more species • Participants may be benefited, harmed or unaffected by the relationship • Results of co-evolution Types: Predation, Mutualism, Commensalism

17. Predation • Predation- the use of one species as a resource by another species. • True predators • Herbivores • Parasites • Parasitoids

18. Predation True Predators • The consumption of one species by another • Many predator-prey interactions • Most common is pursuit and ambush

19. Predation Herbivores

20. PredationParasites • Symbiotic relationship in which one species is benefited and the other is harmed • Parasites rarely kill their hosts • Ex: Varroa mites and honeybees

21. PredationParasites • Symbiotic relationship in which one species is benefited and the other is harmed • Parasites rarely kill their hosts

22. PredationParasitoids

24. Plant Defenses Against Predation • Plants cannot flee predators • Adaptations • Spikes, thorns, leathery leaves, thick wax • Protective chemicals that are poisonous or unpalatable

25. Animal Defenses Against Predation • Fleeing or running • Mechanical defenses • Living in groups • Camouflage • Chemical defenses • Mimicry

26. Prey Defenses-Mimicry

27. Prey Defenses

28. Commensalism (+ 0) • Ex: epiphytes and tropical trees • Mosses • Cattle Egret & Livestock

30. Mutualism (+ +) Ants & Accacia Trees

31. Mutualism (+ +) • Plats & Pollinators • Coral/zooxanthellae • Lichens • Mycorrihzalfungi and plant roots

32. 32