Introduction To Ecology

1. Introduction To Ecology Ch. 50

2. Introduction To Ecology • Ecology – the scientific study of the interactions between organisms and their environments • Ecology determines both the distribution and abundance of organisms • Distribution and abundance depends on abiotic (non-living factors such as temperature, light, water, nutrients, pH, etc.) and biotic (living factors such as all the living organisms) components of the environment

3. Levels of Ecological Study • Organismal Ecology – morphological, physiological, and behavioral way in which individual organisms meet the challenges posed by their abiotic and biotic environments

4. Levels of Ecological Study A population is a group of individuals of the same species living in a particular geographic area • Population Ecology – factors that affect how many individuals of a particular species live in an area

5. Levels of Ecological Study A community consists of all the organisms of all the species that inhabit a particular area; it is an assemblage of populations of many different species • Community Ecology – the whole array of interacting species in a community (includes predation, competition, and disease)

6. Levels of Ecological Study An ecosystem consists of all the abiotic factors in addition to the entire community of a species that exist in a certain area; may consist of many different communities • Ecosystem Ecology – the emphasis in on the energy flow and the cycling of chemicals among the various biotic and abiotic components

7. Levels of Ecological Study • The Biosphere is the global ecosystem, the layer of Earth inhabited by life; the sum of all the plant’s ecosystems

8. Factors Affecting Distribution • Biogeography – the study of the past and present distribution of individual species • In studying the dispersal of organisms, ecologists work through a series of logical steps to determine what limits geographical distributions

9. Factors Affecting Distribution • Of course, we do not want to purposely introduce organisms to areas where they do not already exist • Examples – African Honeybee (purposely) and Zebra Mussel (accidentally) • Tens Rule – one out of ten introduced species becomes established, and one out of ten established species become common enough to become pests.

11. Factors Affecting Distribution • Behavior and habitat selection • Habitat selection by ovipositing insects, which often choose only certain host plants, may limit their distribution • Biotic Factors • The inability to survive and reproduce may be due to predation, disease, or competition • Abiotic Factors • Temperature, water, sunlight, wind, and rocks and soil

12. Factors Affecting Distribution • Temperature and moisture are the major climatic factors determining distribution • Climate is the prevailing weather conditions of a locality and are influenced by temperature, water, light, and wind • Biomes are major types of ecosystems found in broad geographic regions

13. Solar Radiation and Latitude

14. What Causes Seasons?

16. Lake Stratification and Seasonal Turnover

17. Aquatic Biomes • Freshwater biomes – less than 1% salt concentration • Marine biomes – average of 3% salt concentration • Oceans influence global rainfall, climate, and wind patterns • Marine algae and photosynthetic bacteria produce a large portion of the world’s oxygen and consume enormous amounts of carbon dioxide

18. Aquatic Biomes

19. Freshwater Biomes

20. Freshwater Biomes A Eutrophic Lake An Oligotrophic Lake A River

21. Freshwater Biomes • Wetlands – areas covered with water and supporting hydrophytes (water plants); range from marshes to swamps to bogs • These richly diverse biomes are important to flood control and water quality

22. Freshwater Biomes • Estuaries – where a freshwater river or stream meets the ocean; often bordered by wetlands called mudflats and saltmarshes • Serve as feeding and breeding areas for marine invertebrates, fish, and waterfowl

23. Marine Biomes

24. Marine Biomes • Intertidal zones – the daily cycle of tides exposes the shoreline to variations in water, nutrients, and temperature, and to the mechanical force of wave action • Rocky intertidal zones have organisms adapted to firmly attach to the hard substrate • Sand or mudflat intertidal zones are home to burrowing worms, clams, and crustaceans

25. Marine Biomes • Coral reefs – found in tropical waters in the nertic zone; are highly diverse and productive biomes • Coral reefs are easily damaged by pollution, development, native and introduced predators, and high water temperatures

26. Marine Biomes • Benthos – nutrients reach the benthic zone as detritus falling from the waters above. • Nertic benthic communities receive sunlight and are very diverse and productive • Various invertebrates and fishes that are adapted to cold, dark, and high water pressure inhabit the abyssal zone • Chemoautotrophic prokaryotes are adapted to the hot, low-oxygen environment surrounding deep-sea hydrothermal vents

27. Terrestrial Biomes

28. Terrestrial Biomes • The geographic distribution of the world’s major terrestrial biomes is related to abiotic factors – in particular, the prevailing climate • Biomes are usually named for their predominant vegetation and major climatic features • Each bio also has characteristics microorganisms, fungi, and animals

29. Tropical Forests • Occur within 23° latitude of the equator • Variation in rainfall result in tropical dry forests, tropical deciduous forests, and tropical rain forests, where rainfall is abundant

30. Savanna • Tropical and subtropical grassland with scattered trees and rainy and dry seasons • Fires and large grazing mammals restrict vegetation to grasses and small broad-leaved plants

31. Deserts • Characterized by low and unpredictable precipitation • May be hot or cold depending on location • Desert animals have physiological and behavioral adaptations to dry conditions • Plants may use CAM photosynthesis and have water storage adaptations and protective spines and poisons

32. Chaparral • Common along coastlines in midlatitudes that have mild, rainy winters and hot, dry summers • The dominant vegetation – dense, spiny evergreen shrubs – is maintained by and adapted to periodic fires

33. Temperate Grasslands • Maintained by fire, seasonal drought, and grazing by large mammals • Soils are deep and rich in nutrients

34. Temperate Deciduous Forests • Characterized by broad-leaved deciduous trees • Grow in midlatitude regions that have adequate moisture to support the growth of large trees • Trees drop their leaves before winter

35. Coniferous Forest (Taiga) • A large biome found in northern latitudes • Characterized by harsh winters with heavy snowfall • Coniferous trees grow in dense, uniform stands • Coastal temperate rain forests area also coniferous forests

36. Tundra • The northernmost limit of plant growth • Characterized by dwarfed or mat-like vegetation • The alpine tundra, found at all latitudes on high mountains above the tree line, has similar flora and fauna • The artic tundra has a shallow root layer due to permafrost, permanently frozen soil