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Ecosystem Diversity

Ecosystem Diversity. Importance of Diversity. Stability- stable environment Genetic reserves- genetic diversity Medicinal- medicines Agricultural- food Industrial- building homes; things we use Scientific- experimental; new technology Aesthetic- beautiful

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Ecosystem Diversity

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  1. Ecosystem Diversity

  2. Importance of Diversity • Stability- stable environment • Genetic reserves- genetic diversity • Medicinal- medicines • Agricultural- food • Industrial- building homes; things we use • Scientific- experimental; new technology • Aesthetic- beautiful • Ethical- what should we do regarding the environment • Religious- religious beliefs regarding environment

  3. Diversity Increasers Diversity Decreasers • Diverse habitats • Disturbances in habitats (fires, storms) • Trophic levels with high diversity • Middle states of succession • Evolution • Environmental stress • Extreme environments • Introduction of new species from different areas • Extreme limitations on the supply of a fundamental resource • Geographic isolation

  4. Diversity of species • Biodiversity attempts to describe diversity at 3 levels: • Ecosystem- the variety of ecosystems within a region • Species- the variety of species within a given ecosystem • Genetic- the variety of genes within a given species

  5. Species Richness vs. Species Evenness • Species richness- number of species in a given area • Species evenness- relative proportion of different species in a given area

  6. Phylogenies • The branching patterns of evolutionary relationships • Also known as a phylogenetic tree • Shows where speciation occurred

  7. Types of evolution • Microevolution- evolution occurring below the species level • Macroevolution- evolution that gives rise to new species, genera, families, classes, or phyla

  8. Creating Genetic Diversity • Genotype- blueprint for complete set of traits that organism potentially possess • Phenotype- actual set of trait being expressed • 2 process creating diversity: • Mutation • Recombination

  9. Artificial Selection vs. Natural selection

  10. Artificial Selection • Has produces numerous breeds of cattle, hogs, chickens, fruits, and vegetables

  11. Natural Selection • How organisms evolve • “Survival of the Fittest” • Those organisms most fit in their environment will survive, reproduce, and pass on those adaptive traits to their offspring • The range of genetic variation within a species’ gene pool determines whether or not the species, not the individual, has the ability to adapt and survive changes in the environment.

  12. Evolution by random Processes • Mutation • If not lethal, can add genetic variation to a population • Genetic Drift • Change in composition of a population due to random mating • Bottleneck Effect • Reduction in genetic diversity caused by a reduction in size • Founders Effect • Colonizing individuals will give raise to a new population

  13. Evidence of Evolution • Fossil Record • Homologous structures • Vestigial Structures • Embryology • DNA/ protein comparisons

  14. COMMUNITY STRUCTURE AND SPECIES DIVERSITY- Day 2 • Biological communities differ in their structure and physical appearance. Figure 7-2

  15. Types of Natural Selection

  16. Geographic Isolation • …can lead to reproductive isolation, divergence of gene pools and speciation. Figure 4-10

  17. Climate Shift • Natural Climate Shifts • Geologic Time • 6 glacial periods • 1500-1800 Time of cooling • Mid1800-Present – Time of warming • Result of human activities??? • Examples • Volcanoes • Continental drift • Earth’s tilt • Geomagnetic reversal

  18. Species Movement • Faced with Change • Adapt, migrate, or die • Plants • Seeds blow in the wind, attach to animals, pass through digestive system of animals • Animals • Can migrate over long distances as long as a suitable habitat is within reach

  19. All things change… • All communities change • In response to changing environmental conditions • Ecological succession – a gradual change in species composition of a given area • Colonizing or pioneer species arrive first • Could also be replaced as the conditions change. • Two types of successions • Primary • Lifeless  Life (gradual) • Secondary • Series of communities develop

  20. Starting from scratch • Primary succession • Lifeless  Life • Examples: Barren rock, newly cooled lava, a newly created pond, or abandoned highway or parking lot • Gradual Process • Why? – No fertile soil to provide nutrients • Wait for the sloooooow process of soil formation • This begins with such pioneer species such as lichens and moss that can attach themselves to bare rock.

  21. Pioneer Communities • Lichens and moss.

  22. Primary succession • Soil Formation • Start with: • Trapping of soil particles and organic matter • Secreting mild acids that slowly break down the rock • Also helped along physical weathering • After 100s – 1000s of years • Soil may be deep and fertile enough • Support midsucessional plants • Herbs, grasses, and low shrubs  Trees that need lots of sunlight will eventually replace these species

  23. Primary succession • Late successional plant species • As the above trees grow they create shade and are replaced by species that tolerate shade • Unless disturbed by man or nature what was once barren rock is now a complex forest community. • Oligotrophic ponds • Runoff  Sediment • Sediment can support seeds carried by winds or birds • Pond  Marsh  Dry land

  24. Starting over • Secondary succession • Disturbed or destroyed community • Examples: Abandoned farm lands, burned or cut forests, heavily polluted streams, and land that has been flooded. • Some soils and bottom sediment still remains • Plants can grow quickly

  25. Secondary Succession

  26. Climax Communities • The area dominated by a few, long-lived plant species.

  27. Stages • Land – rock  lichen  small shrubs  large shrubs  small trees  large trees

  28. Water – bare bottom  small/few underwater vegetation  temporary pond and prairie  forest and swamp

  29. 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.

  30. Niche • The total way of life or role of a species in an ecosystem. • Think of it as the species job. • All the physical, chemical, and biological conditions a species needs to live & reproduce in an ecosystem. • Generalist Species • A species that can live in a broad range of niches. • Live just about anywhere – Think cockroach • Specialist Species • A species that can live in only a few niches • Live in only a couple of places – Think panda

  31. Niche Specialization • Niches become separated to avoid competition for resources. Figure 7-6

  32. Specialized Feeding Niches • Resource partitioning reduces competition and allows sharing of limited resources. Figure 4-8

  33. Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Ruddy turnstone searches under shells and pebbles for small invertebrates Herring gull is a tireless scavenger Brown pelican dives for fish, which it locates from the air Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Black skimmer seizes small fish at water surface Louisiana heron wades into water to seize small fish Flamingo feeds on minute organisms in mud Scaup and other diving ducks feed on mollusks, crustaceans,and aquatic vegetation Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Piping plover feeds on insects and tiny crustaceans on sandy beaches Knot (a sandpiper) picks up worms and small crustaceans left by receding tide (Birds not drawn to scale) Fig. 4-8, pp. 90-91

  34. Evolutionary Divergence • Each species has a beak specialized to take advantage of certain types of food resource. Figure 4-9

  35. Resource Partitioning • Each species minimizes competition with the others for food by spending at least half its feeding time in a distinct portion of the spruce tree and by consuming somewhat different insect species. Figure 7-7

  36. Roles of Species • Critical Roles • Pollination • Bees, bats, butterflies, and hummingbirds • Top predator • Regulate populations of other species • Wolf, leopard, lion, alligator, and shark • Decomposers • Dung Beetles • Remove dung • Aerate the soil • Keystone species • Species that play roles affecting many other organisms in an ecosystems • Eliminating a keystone species may dramatically alter the structure and function of a community

  37. Roles of Species • Indicator Species • Serve as harbingers of damage to a community or ecosystems • Examples • Coral Reef • Trout in Streams • Birds • Canaries

  38. Case Study -Why are amphibians vanishing? • Amphibians • Frogs, toads, and salamanders • Very vulnerable to environmental disruptions at all stages of the life cycle. • No UV protection for the eggs. • Very thin skin • Susceptible to pollutants

  39. Population Crash • Since 1980 • Total of 6,000 species • 32% are threatened with extinction • 43% of all species are declining • More than 80% of the Caribbean’s species are threatened by habitat loss and disease • No singular cause • Habitat loss, fragmentation, and Climate change • Prolonged drought • Pollution-Increase in UV • Parasites/Diseases/Overhunting/Invasive Species

  40. Why should we care? • Three reasons • Environmental health is failing • Remember they are indicator species • Role that they play • Eat more mosquitoes than birds • Extinction of other species that depend on amphibians for food • Genetic storehouse • Secretions have been used as painkillers and antibiotics

  41. Types of Species • Native • Normally live in a given location • Example: • Armadillo • Bluebonnets • Horned Toad

  42. Types of Species • Endemic Species • Island species • Found nowhere else in the world (rare) • Very vulnerable to extinction • Examples • Lemurs

  43. Types of Species • Nonnative • Migrate or Accident • AKA: • Invasive • Alien • Not always a villains • Most domesticated plants and animals are nonnative • Examples • Fire Ants • Africanized Honey Bees • Zebra Mussels

  44. Types of species • Invasive species • 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. Kudzu vine was introduced in the southeastern U.S. to control erosion. It has taken over native species habitats. Figure 11-A

  45. INVASIVE SPECIES • The Argentina fire ant was introduced to Mobile, Alabama in 1932 from South America. • Most probably from ships. • No natural predators. Figure 11-12

  46. Species Interactions • Competition • Species vie for shared or limited resources such as space and food • Interspecific – different • Intraspecific - same • One species is more efficient at obtaining resources

  47. Species Interactions • Mutualism • Two species or a network of species interact in such a way that benefits both. • Bees and flowers • Can you think of another example? • Usually combines nutrition and protection

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