THE NATURE OF ECOLOGY

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2 THE NATURE OF ECOLOGY Ecology is a study of connections in nature. How organisms interact with one another and with their nonliving environment. Figure 3-2

3 What do you mean by environment? The environment is made up of two factors: Biotic factors- all living organisms inhabiting the Earth Abiotic factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, air currents)

4 Autotrophs = Producers = Self feeders

5 How Ecosystems Use Sunlight As Their Source of Energy

6 Producers: Basic Source of All Food Most producers capture sunlight to produce carbohydrates by photosynthesis:

7 Producers: Basic Source of All Food Chemosynthesis: Some organisms such as deep ocean bacteria draw energy from hydrothermal vents and produce carbohydrates from hydrogen sulfide (H 2 S) gas.

8 Consumers: Eating and Recycling to Survive Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Herbivores Primary consumers that eat producers Carnivores Secondary consumers eat primary consumers Third and higher level consumers: carnivores that eat carnivores. Omnivores Feed on both plant and animals. Scavengers Feed on dead leftovers, lazy hunters.

9 Consumers = Heterotrophs Primary consumers = herbivores = rabbit: eat plant material Secondary consumers = carnivores = predators = coyotes: prey are herbivores and other animals.

10 Decomposers and Detrivores Detrivores: Insects or other scavengers that feed on organic matter (wastes or dead bodies), breaking it down. Decomposers: Recycle nutrients in ecosystems. (Intake organic matter and convert to inorganic substances. Bacteria and fungi Figure 3-13

11 ENERGY FLOW IN ECOSYSTEMS Food chains and webs show how eaters, the eaten, and the decomposed are connected to one another in an ecosystem. Figure 3-17

12 Food Webs Trophic levels are interconnected within a more complicated food web. Figure 3-18

13 Biomass Pyramid Biomass amount of living matter

14 Bioaccumulation Occurs in one trophic level. Toxins build up in the tissues of an affected organism Persistence ability of a substance to remain in an organism Ex) DDT and Mercury

15 Biomagnification Occurs across multiple trophic levels Each trophic level accumulates more toxins than the lower level. Higher level consumers have higher concentrations of toxins

16 Productivity of Producers: The Rate Is Crucial Gross primary production (GPP) Rate at which an ecosystem s producers convert solar energy into chemical energy as biomass. Figure 3-20

17 Some Terms and Definitions Ecosystems: A grouping of plants, animals, and microbes occupying an explicit unit of space and interacting with each other and their environment. Biotic with abiotic (living with non-living) Ecotone: Transitional region between different ecosystems.

18 Ecotones Shares many of the species and characteristics of both ecosystems Borders may be: sharp or fuzzy Narrow or wide Small or large May also include unique conditions that support distinctive plant and animal species Shares many of the species and characteristics of both ecosystems

19 Riparian Zone Ecotone between land and a river/stream. Important in soil conservation and habitat biodiversity

20 Biosphere Atmosphere Membrane of air around the planet. Stratosphere Lower portion contains ozone to filter out most of the sun s harmful UV radiation. Hydrosphere All the earth s water: liquid, ice, water vapor Lithosphere The earth s crust and upper mantle.

21 Biosphere Ecosystem Community Population Organism

22 Biosphere- life supporting portions of Earth composed of air, land, fresh water, and salt water. The highest level of organization

23 Ecosystem- populations in a community and the abiotic factors with which they interact (ex. marine, terrestrial)

24 Community- several interacting populations that inhabit a common environment and are interdependent.

25 Population-a group of organisms of one species living in the same place at the same time that interbreed and compete with each other for resources (ex. food, mates, shelter)

26 Organism- any unicellular or multicellular form exhibiting all of the characteristics of life, an individual. The lowest level of organization

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28 ECOLOGICAL STABILITY Living systems maintain some degree of stability through constant change in response to environmental conditions through: Inertia (persistence): the ability of a living system to resist being disturbed or altered. Constancy: the ability of a living system to keep its numbers within the limits imposed by available resources. Resilience: the ability of a living system to bounce back and repair damage after (a not too drastic) disturbance.

29 Factors that affect population growth Carrying Capacity- the maximum population size that can be supported by the available resources There can only be as many organisms as the environmental resources can support

30 None Limiting Factor- Zone of Tolerance Few organisms present Many organisms present Few organisms present None

31 Factors that affect population growth Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment. EX.- Amount of water Amount of food Temperature ph Salinity

32 Carrying Capacity N u m b e r J-shaped curve (exponential growth) Carrying Capacity (k) Minimum S-shaped curve (logistic growth) Time

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35 Niche The role a species plays in a community Determined by limiting factors Habitat The place where an organism/population lives out its life

36 ECOLOGICAL NICHES AND ADAPTATION Each species in an ecosystem has a specific role or way of life. Fundamental niche: the full potential range of physical, chemical, and biological conditions and resources a species could theoretically use. Realized niche: to survive and avoid competition, a species usually occupies only part of its fundamental niche.

37 Generalist and Specialist Species: Broad and Narrow Niches Generalist species tolerate a wide range of conditions. Specialist species can only tolerate a narrow range of conditions. Figure 4-7

38 Reproductive Patterns: Opportunists and Competitors Large number of smaller offspring with little parental care (rselected species). Fewer, larger offspring with higher invested parental care (Kselected species). Figure 8-9

39 Cockroaches: Nature s Ultimate Survivors 350 million years old 3,500 different species Ultimate generalist Can eat almost anything. Can live and breed almost anywhere. Can withstand massive radiation. Figure 4-A

40 Two Reproductive Strategies R Strategists Short life span Small body size Reproduce quickly Have many young Little parental care Early reproductive age Generalists Ex: cockroaches, weeds, bacteria

41 Two Reproductive Strategies K Strategists long life span large body size reproduce slowly have few young provides parental care Late reproductive age Specialists Ex: elephants, bears

42 Survivorship Curves: Short to Long Lives The way to represent the age structure of a population is with a survivorship curve. Late loss population live to an old age. Constant loss population die at all ages. Most members of early loss population, die at young ages.

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44 Biodiversity Hotspots a region with a significant reservoir of biodiversity that is under threat from humans. it must contain at least 1,500 species of endemic vascular plants, and it has to have lost at least 70% of its primary vegetation. Globally, 25 areas qualify under this definition, with nine others possible candidates. These sites support nearly 60% of the world's plant, bird, mammal, reptile, and amphibian species.

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47 Species Diversity Biological communities differ in the types and numbers of species they contain and the ecological roles those species play. Species diversity: the number of different species it contains (species richness) combined with the abundance of individuals within each of those species (species evenness).

48 Species Diversity and Niche Structure Niche structure: how many potential ecological niches occur, how they resemble or differ, and how the species occupying different niches interact. Geographic location: species diversity is highest in the tropics and declines as we move from the equator toward the poles.

49 Genetic Diversity Individuals of the same species vary slightly in their genetic makeup and morphology. The greater the amount of diversity, the more fit a species is to survive.

50 Survival of the fittest Natural Selection Those best suited to the environment survive and reproduce passing their genes to subsequent generations Can lead to speciation

51 Evolution Speciation is the evolutionary process by which new biological species arise change in the inherited characteristics of biological populations over successive generations

52 Resource Partitioning Competition over resources drives species into different patterns of resource use Leads to niche specialization

53 Specialized Feeding Niches Black skimmer seizes small fish at water surface Brown pelican dives for fish, which it locates from the air Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Herring gull is a tireless scavenger Ruddy turnstone searches under shells and pebbles for small invertebrates Flamingo feeds on minute organisms in mud Scaup and other diving ducks feed on mollusks, crustaceans,and aquatic vegetation (Birds not drawn to scale) Louisiana heron wades into water to seize small fish Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Piping plover feeds on insects and tiny crustaceans on sandy beaches

54 Niche Specialization Over time, species who compete over a shared resource tend to evolve in ways that reduce competition leading to a divergence of the two species.

55 Evolutionary Divergence All of the finches in the diagram are descended from a common ancestor Each species has evolved a beak specialized to take advantage of certain types of food. Figure 4-9

56 Island Biogeography MacArthur and Wilson proposed the species equilibrium model or theory of island biogeography in the 1960 s. Model projects that at some point the rates of immigration and extinction should reach an equilibrium based on: Island size Distance to nearest mainland (degree of isolation) Length (time) of isolation

57 Insular Dwarfism mainland forms of mammals sometimes evolve into far smaller forms on resourceconstrained islands. (e.g., pygmy elephants, or pygmy humans)

58 Indicator Species: Canary in a Coal Mine Species that serve as early warnings of damage to a community or an ecosystem. Frogs (and other amphibians) are good indicators since they live in both land and water and are sensitive to changes in the environment Presence or absence of trout species because they are sensitive to temperature and oxygen levels.

59 Keystone Species: Major Players a species that has a disproportionately large effect on its environment relative to its abundance and play a critical role in maintaining the structure of a community, affecting many other organisms and helping to determine the types and numbers of various other species in the community.

60 Keystone Species Species that play roles affecting many other organisms in an ecosystem. Examples: Bees/butterflies (pollination) Top predators like wolf, lion, alligator (population control) Dung beetles (waste management, soil aeration)

61 American Alligators Dig deep depressions (gator holes). Hold water during dry spells, serve as refuges for aquatic life. Build nesting mounds. provide nesting and feeding sites for birds. Keeps areas of open water free of vegetation.

62 Reintroducing Wolves to Yellowstone Keystone Species Keeps prey away from open areas near stream banks. Vegetation reestablishes. Species diversity expands. Between two million wolves were destroyed.

63 Foundation Species Can create and enhance habitats that can benefit other species in a community. Examples: Elephants (uproot trees creating forest openings for grasslands) Beavers (dams create wetlands or redirect/pool water)

64 SPECIES EXTINCTION Species can become extinct: Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world. (Extirpated) Ecologically: Occurs when so few members of a species are left they no longer play its ecological role. Globally (biologically): Species is no longer found on the earth.

65 Global Extinction Some animals have become prematurely extinct because of human activities.

66 Endangered and Threatened Species Endangered species: so few individual survivors that it could soon become extinct. Threatened species: still abundant in its natural range but is likely to become endangered in the near future.

67 Convention on International Trade in Endangered Species of Wild Fauna and Flora Its aim is to ensure that international trade in specimens of wild animals and plants does not threaten the survival of the species in the wild, and it accords varying degrees of protection to more than 33,000 species of animals and plants.

68 The U.S. Endangered Species Act Passed in 1973 (ESA) ESA forbids federal agencies (besides defense department) to carry out / fund projects that would jeopardize an endangered species. ESA makes it illegal for Americans to engage in commerce associated with hunting / killing / collecting endangered or threatened species.

69 Because of scarcity of inspectors, probably no more than 1/10 th of the illegal wildlife trade in the U.S. is discovered.

70 SPECIES EXTINCTION Some species have characteristics that make them vulnerable to ecological and biological extinction. Figure 11-4

71 Species vulnerability to extinction Low reproductive rate Specialists High trophic level Rare Commercially valuable Large territories/migration routes

72 Causes of premature extinction Habitat destruction, degradation, and fragmentation Invasive species Population growth Pollution Climate Change Overharvest (HIPPCO)

73 Reduction in ranges of four wildlife species, mostly due to habitat loss and overharvesting. Figure 11-8

74 Terminology From here Native (Organisms brought to a location without the help of man, such as by wind, wave and or birds. ) Indigenous (Organisms that are native but can be found elsewhere.) Endemic (Organisms that are native and can be found ONLY in that location.) Not from here Non-native Exotic Introduced Alien Invasive

75 NON-NATIVE SPECIES Kudzu vine was introduced in the southeastern U.S. to control erosion. It has taken over native species habitats. Many nonnative species provide us with food, medicine, and other benefits but a few can wipe out native species, disrupt ecosystems, and cause large economic losses.

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77 NON-NATIVE SPECIES intentionally introduced Purple loosestrife European wild boar African honeybee Nutria Hydrilla

78 NON-NATIVE SPECIES Unintentionally Introduced Zebra mussel Asian tiger mosquito Snakehead Fire ant

79 Beneficial non-natives Corn (Mexico) Oats (Switzerland) Wheat (southwestern Asia Syria, Jordan, Turkey) Rice (India/Nepal) Cattle (Europe) Poultry (Asia-India) Honey bees (Asia/Europe)

80 Characteristics of Successful Invader Species High reproductive rate, short generation time (r-selected species) Pioneer species Long lived High dispersal rate Release growth-inhibiting chemicals into soil Generalists High genetic variability Characteristics of Ecosystems Vulnerable to Invader Species Climate similar to habitat of invader Absence of predators on invading species Early successional systems Low diversity of native species Absence of fire Disturbed by human activities Fig , p. 236

81 How to be a successful invader Be a pioneer species (lichens, mosses) Have a high reproductive rate, short generation time (r-selected species) Have a high dispersal rate Have an adaptation that is harmful to other competing organisms (e.g., releasing chemicals into soil that inhibit other plants from growing Be a Generalist Have high genetic variability

82 Which ecosystems are vulnerable to invasion? Climate similar to habitat of invader Absence of predators on invading species Low diversity of native species Absence of fire Disturbed by human activities

83 Types of Population Change Curves in Nature Population sizes may stay the same, increase, decrease, vary in regular cycles, or change erratically. Stable: fluctuates slightly above and below carrying capacity. Irruptive: populations explode and then crash to a more stable level. Cyclic: populations fluctuate and regular cyclic or boomand-bust cycles. Irregular: erratic changes possibly due to chaos or drastic change.

84 Types of Population Change Curves in Nature Population sizes often vary in regular cycles when the predator and prey populations are controlled by the scarcity of resources. Figure 8-7

85 PREDATION ways in which prey species avoid their predators: Speed outer protection Camouflage chemical warfare warning coloration mimicry deceptive looks deceptive behavior. Figure 7-8

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87 Outer Protection

88 Camouflage

89 Find the frogs! Did you find all 4?

90 Chemical Warfare

91 Warning Coloration

92 Mimicry Fig. 7-8f, p. 153

93 Deceptive Looks

94 Deceptive Behavior This is a snake caterpillar. It is a caterpillar that (when threatened) expands the tail end of its body to resemble a snake head

95 Symbiosis Parasitism Mutualism Commensalism Ammensalism

96 Parasites: Mooching Parasites do not usually kill their host (at least not quickly) as opposed to predation. Some parasites live in host (micro-organisms, tapeworms). Some parasites live outside host (fleas, ticks, mistletoe plants, sea lampreys). Some have little contact with host (dump-nesting birds like cowbirds, some duck species)

97 Mutualism: Win-Win Relationship Two species can interact in ways that benefit both of them.

98 Commensalism: Using without Harming Some species interact in a way that helps one species but has little or no effect on the other. Figure 7-10

99 Ammensalism Ecological interaction in which an individual harms another without obtaining benefit Red tide, proliferation of algae that can lead to death of fishes and other animals