Introduction to Ecology Chapter 50

1. Introduction to EcologyChapter 50

2. What is ecology? • Ecology is the study of how organisms interact with their environment; • “Eco” from “Oiko” = “home” • What factors control the distribution and abundance of organisms?

3. Organismal (physiological and behavioral) • Population • Community • Ecosystem • Global 1. Types of Ecology

4. Organismal ecology • Questions center on how organisms respond to biotic and abiotic factors in their environment • Physiology, morphology, and behavior

5. Population ecology • A population is a group of organisms of the same species living in the same place at the same time. • Questions are related to factors that affect the number of individuals living in a habitat – size, distribution of population? - birth and death rates? - population growth rate?

6. Community ecology • A community consists of the organisms that live in an area and interact • Questions focus on • the interactions between organisms (who eats who, who helps who) • how those interactions affect community structure

7. Mutualism Competition Species Interactions Predators and parasites

8. Ecosystem ecology • An ecosystem consists of the biotic (living) community and the abiotic (nonliving) factors that affect it. • Abiotic factors are things such as soil, atmosphere, water, nutrients, energy, temperature • Questions emphasize energy flow and cycling of nutrients

9. Global ecology • Controls and patterns of worldwide circulation of energy and nutrients • Factors that affect climate Atmospheric CO2 and Temp.

10. 2. What factors affect the distribution of organisms? • Species dispersal • Behavior and habitat selection • Biotic factors-Other organisms such as predators, competitors, or facilitators • Abiotic factors such as nutrient availability, water, temperature

11. What affects the distribution of organisms? Fig. 50.6 Flowchart of factors limiting geographic distribution. As ecologists study the factors limiting a species’ distribution, they often consider a series of questions like these.

12. Transplantation studies can give us information about potential ranges. Species dispersal Species may not inhabit an area because of biogeographical boundaries. Fig. 50.6

13. Application: Introduced species - Breakdown in dispersal barriers- Most do not cause problems- Some do- Problems can be large, expensive, and difficult or impossible to reverse Fig. 50.8 – Zebra mussel

14. Behavior and habitat selection • Organisms do not always occupy all available, suitable habitat • May be specific in reproduction needs • In insects- larval needs may be different from adult needs

15. Biotic factors • Interactions with other organisms • Negative: predation or competition • Positive: facilitation (e.g., pollinators urchin vs. limpets Fig. 50.9

16. Abiotic factors • Temperature • high temperature cause cell membranes to leak and enzymes to stop working • low temperature causes freezing • some animals have antifreezes that allow them to survive below freezing temperatures. Fig. 27.1 – thermophilic bacteria, Nevada Antarctic notothenioids

17. Abiotic factors • Water availability • too little water (desiccation) • Deserts, saltwater • too much water (anaerobic) Mangroves Organ pipe cacti, desert shrubs

18. Abiotic factors – Water availability All terrestrial organisms Leaves, stomata Insects – tolerate, cuticle

19. Abiotic factors • Sunlight • Competition, shade tolerance for plants • Photic zone, different wavelengths for aquatic organisms

20. Abiotic factors • Wind • exacerbates the effects of temperature and water loss • also exerts forces on organisms (waves act in the same manner) Flagging of tree limbs due to wind

21. Temperature • Temperature is partly determined by the amount of solar radiation hitting an area • Depends on latitude, angle of incidence Fig. 50.11

22. What causes the seasons? • We know: • Earth has elliptical orbit • Earth is tilted on axis (23.5o) • Seasons are opposite in northern and southern latitudes • It can NOT be the distance of the earth from the sun since the seasons are opposite in the northern and southern hemispheres.

23. Temperature • Seasons are caused by the tilt of the earth as it revolves about the sun Fig. 50.12

24. Water • Warming air absorbs water and cooling releases water, causing more rain at some latitudes Fig. 50.13

25. Water • Wind patterns interact with mountains to cause increased rain on windward sides, rain shadows on lee sides. Fig. 50.14 How mountains affect rainfall.

26. Microclimates • Within a biome, region or habitat, temp., water, sunlight and other factors can vary dramatically • These form small areas with microclimates or microhabitats • Can have strong effects on species ranges Fig. 50.26

27. Aquatic biomes cover about 75% of the earth’s surface • Wetlands • Oceanic pelagic • Lakes • Rivers, streams • Intertidal zones • Coral reefs • Benthos

28. 1. Lakes Oligotrophic Lake: Nutrient poor, water is clear, oxygen rich; little productivity by algae, relatively deep with little surface area.

29. 1. Lakes • Eutrophic lake: nutrient rich, lots of algal productivity so it’s oxygen poor at times, water is murkier  often a result of input of agricultural fertilizers

30. Rivers and Streams: Organisms need adaptations so that they are not swept away by moving water; heavily affected by man changing the course of flow (E.g. dams and channel-straightening) and by using rivers to dispose of waste.

31. Wetlands: includes marshes, bogs, swamps, seasonal ponds. Among richest biomes with respect to biodiversity and productivity.Very few now exist as they are thought of often as wastelands.

32. Estuary: Place where freshwater stream or river merges with the ocean. Highly productive biome; important for fisheries and feeding places for water fowl. Often heavily polluted from river input so many fisheries are now lost.

33. Intertidal Zone: Alternately submerged and exposed by daily cycle of tides. Often polluted by oil that decreases biodiversity.

34. Coral Reefs: occur in neritic zones of warm, tropical water, dominated by cnidarians (corals); very productive, protect land from storms; most are now dying from rise in global temperatures

35. Deep-sea vent: Occurs in benthic zone; diverse, unusual organisms; energy comes not from light but from chemicals released from the magma.

36. Biomes • Regions of the earth that are similar in organism type although the particular species differ • Driven largely by climate – temp., water, seasonality • Other factors – soil, topography Fig. 50.10 – Biomes of North America

37. BIOMES

38. Any Questions??