The document discusses key concepts in ecology including species, populations, communities, and ecosystems. It defines each of these levels of ecological organization from organisms to the biosphere. Species are composed of one or more populations whose members can interbreed. Populations are groups of the same species in a given area. Communities are sets of populations that live together. Ecosystems include both biotic factors like organisms and abiotic factors like climate, along with their interactions. For a species to occur in a place, it must be able to get there, survive the environmental conditions, and reproduce.

1. Ecology I: Species, Populations, Communities and Ecosystems Ecology I Species interactions, Populations, Communities and Ecosystems

2. ECOLOGY Ecology : the scientific study of relationships between organisms and their environment Includes the study of the ecosystem structure and function Ecology I: Species, Populations, Communities and Ecosystems

3. Ecologist vs. Environmentalist Is an ecologist an environmentalist? No, not necessarily An ecologist is a scientist studying how ecosystems work and the relationship between organisms and their environment An environmentalist is an individual interested in the environment (and may or may not be a scientist) Ecology I: Species, Populations, Communities and Ecosystems

4. Levels of organization in the living world: large scale to small scale Ecology I: Species, Populations, Communities and Ecosystems

5. Biosphere Ecosystem Community Population Organism The sum total of living things on Earth and the areas they inhabit A functional system consisting of a community, its nonliving environment, and the interactions between them A set of populations of different species living together in a particular area A group of individuals of a species that live in a particular area An individual living thing Ecology I: Species, Populations, Communities and Ecosystems

6. Levels of organization in the living world Organism : an individual living thing Classified by ancestry into species 1.75 million named so far Maybe 3-100 million total Ecology I: Species, Populations, Communities and Ecosystems

7. Why are we still so unsure of the number of species on Earth? Some areas remain little explored (hydrothermal vents, rainforest canopies, tropical soils). Many species are tiny and inconspicuous (microbes, roundworms, protists, fungi…). Some species are very similar in appearance (many taxa, even trees, birds, whales). Levels of organization in the living world

8. Species One or more populations Ecology I: Species, Populations, Communities and Ecosystems

9. Species One or more populations whose members actually or potentially interbreed under natural conditions Ecology I: Species, Populations, Communities and Ecosystems

10. Species One or more populations whose members actually or potentially interbreed under natural conditions and produce fertile offspring. Ecology I: Species, Populations, Communities and Ecosystems

11. Levels of organization in the living world Organisms : Population : group of individuals of same species occupying a given area at the same time Ecology I: Species, Populations, Communities and Ecosystems

12. Levels of organization in the living world Organisms: Population: Community : a set of populations of different species occupying a particular place Ecology I: Species, Populations, Communities and Ecosystems

13. Levels of organization in the living world Organisms: Population: Community: Ecosystem: community(ies) interacting with one another and with the physical environment in a particular place Ecology I: Species, Populations, Communities and Ecosystems

14. Levels of organization in the living world Ecosystems : Include abiotic factors such as climate, water, minerals and sunlight as well as biotic factors such as organisms Ecosystems are the fundamental operational unit of ecology Ecology I: Species, Populations, Communities and Ecosystems

15. Ecology I: Species, Populations, Communities and Ecosystems Species: Distribution & Interrelationships

16. What determines whether a species will occur at any given place and time? I. It must be able to get there Evolution, Immigration, Introduction II. It must be able to survive there Biological and Physical Environment III. It must be able to reproduce there Suitable mates and environment, etc. Ecology I: Species, Populations, Communities and Ecosystems

17. I. Getting there 1. Evolution 2. Immigration: range expansion Ecology I: Species, Populations, Communities and Ecosystems

18. I. Getting there 1. Evolution 2. Immigration 3. Introduction introduced = exotic = alien species versus native and endemic species Ecology I: Species, Populations, Communities and Ecosystems

19. Introduction: Exotic Species Ecology I: Species, Populations, Communities and Ecosystems European Starling

20. Ecology I: Species, Populations, Communities and Ecosystems

21. II. Surviving there 1. Physical environment 2. Biological environment Ecology I: Species, Populations, Communities and Ecosystems

22. II. Surviving there: Habitat An organism’s place or type of place in which it lives and thrives. Includes food, water, cover, and space Microhabitat : the part of the habitat the organism is “really” using Ecology I: Species, Populations, Communities and Ecosystems

23. Microhabitat: the part of the habitat the organism is “really” using Ecology I: Species, Populations, Communities and Ecosystems

24. II. Surviving there: Niche What the organism does in its habitat Includes all the physical and biological factors and interactions of the organism Ecology I: Species, Populations, Communities and Ecosystems

25. Ecology I: Species, Populations, Communities and Ecosystems

26. II. Surviving there: Niche Specialists versus Generalists Plants and animals with narrow tolerance ranges and/or specific dietary constraints, etc. = Specialists Plants and animals with wide variety of habitats, foods, etc = Generalists Ecology I: Species, Populations, Communities and Ecosystems

27. II. Surviving there: Niche Specialists versus Generalists Which is more prone to extinction? Ecology I: Species, Populations, Communities and Ecosystems Wolf Coyote

28. II. Surviving there: Niche Which is more prone to extinction? The wolf—a specialist (carnivore)? The coyote—a generalist (omnivore)? Answer: the wolf Ecology I: Species, Populations, Communities and Ecosystems

29. Fundamental versus Realized Niches Ecology I: Species, Populations, Communities and Ecosystems Wolf Coyote Surviving there: Niche Removal of wolf Allowed coyotes To expand to fill Fundamental niche

30. II. Surviving there: Physical Environment 1. Range of tolerance The range of variability in a particular physical factor that an organism can withstand Ecology I: Species, Populations, Communities and Ecosystems

31. II. Surviving there: Physical Environment 1. Range of tolerance What an organism can tolerate depends on… Adaptation : (population level) due to past evolution Acclimation : (individual level) Physiological changes within an individual to slowly changing new conditions Ecology I: Species, Populations, Communities and Ecosystems

32. II. Surviving there: Physical Environment 2. Limiting Factors All it takes is one single factor to be outside of the range of tolerance to limit population growth This factor is called the limiting factor Ecology I: Species, Populations, Communities and Ecosystems

33. Limiting Factors and Saguaro distribution: saguaros are limited to the north by freezing temperatures and to the south by competition with other plants Ecology I: Species, Populations, Communities and Ecosystems

34. II. Surviving there: Biological Environment Mutualism : both gain Predation : predator gains, prey loses Parasitism : parasite gains, host loses Competition : both lose Commensalism : one species benefits; the other is unaffected Biological environment=interrelationships Ecology I: Species, Populations, Communities and Ecosystems

35. INTERRELATIONSHIPS Different ways to get along, or not get along Predation + - Competition - - Parasitism + - Commensalism + o Mutualism + + + = benefit = harmed 0 = unaffected

36. INTERRELATIONSHIPS Mutualism Which Type? Both gain

37. INTERRELATIONSHIPS Competition Which Type? Both the bobcat and coyote lose

38. INTERRELATIONSHIPS Parasitism Which Type? The parasite gains, the host loses

39. INTERRELATIONSHIPS Predation Which Type? Predator gains, Prey loses

40. INTERRELATIONSHIPS Commensalism Which Type? Snake gains home, rodent unaffected (hole abandoned long ago)

41. INTERRELATIONSHIPS: Review Mutualism Which Type? Both gain

42. INTERRELATIONSHIPS: Review Competition Which Type? Both lose available soil moisture

43. III. Reproduce there Ecology I: Species, Populations, Communities and Ecosystems Must find suitable mate Offspring must be able to survive to reproductive age in order to ensure on-going presence of population