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Challenges facing Parasites, hosts as islands, how to infect new ones?High specificity, high fecundities, exploitation of vectors (mosquitoes)Intermediate and final hosts, host altered behavior (rabies, etc.)Assassin bugs (Triatoma)Malaria, protists (Plasmodium)Tapeworms (Cestodes), Nematodes (roundworms)Cholera (Shigella) transmission via dysenteryToilet seats, elevator buttons, door knobs, shopping carts...etc.Molecular mimicry: “eclipsed antigens” resemble host antigens hence do not elicit formation of host antibodiesMajor Histocompatibility Complex (MHC) Trypanosoma (protozoans) shed coats, change antigensFilariasis Elephantiasis (lymph nodes blocked by nematodes carried by mosquitoes)BotfliesDracunculus medinensis, caduceus symbol of medicine
Darwinian Medicine: don’t treat symptoms, distinguish between host defenses and parasite manipulation.Evolution of Virulence (benign parasites allow hosts to live)Host altered behaviorRabies virus — rabid animals bite, passes on virus to new hostLancet fluke Trematode Dicrocoelium dentriticumCercaria —> Metacercariae encyst on ant’s brainSheep ingest an ant and get infectedStarlings, Pill bugs, and AcanthocephalansDucks, Amphipods, and AcanthocephalansSTDs —> increased sexual activity?Ectoparasites (fleas, ticks, lice), endoparasitesSocial parasites (thievery, brood parasitism)Parasitoids: Ichneumonid waspsMicroparasites—> macroparasties—>parasitoids—>predator spectrum and many correlates thereof, such as relative sizes, rates of increase, number of parasites per host, virulence, stability, and ability to regulate lower trophic level
Coevolution
Joint evolution of two (or more) taxa that have
close ecological relationships but do not
exchange genes, and in which reciprocal
selective pressures operate to make the
evolution of either taxon partially dependent
on the evolution of the other
EnterobiusPinworms(Parasiteson Primates)
Parallel phylogenies
Primate hosts Enterobius species
Drosophila pachea and senita cactus.
Danaid butterflies use polyuridine alkaloids as chemical precursors
for synthesis of pheromones used in attracting mates.
An arginine mimic, l-canavanine, present in
many legumes, ruins protein structure in most insects.
However, a bruchid beetle has evolved metabolic machinery
that enable it to use plants containing canavanine.
Wild ginger, Asarum caudatum, in western Washington are
polymorphic for growth rate, seed production, and palatabililty to
a native slug, Ariolimax columbianus (Cates 1975).
Where slugs are uncommon, plants allocate more energy to
growth and seed production and less to production of antiherbivore
chemicals. In habitats with lots of slugs, less palatable plants have
a fitness advantage — even though they grow more slowly, they
lose less photosynthetic tissue to slug herbivory.
Some of the Suggested Correlates of Plant Apparency _____________________________________________________________________________ Apparent Plants Unapparent Plants _____________________________________________________________________________ Common or conspicuous Rare or ephemeral Woody perennials Herbaceous annuals Long leaf life span Short-lived leaves Slow growing, competitive species Faster growing, often fugitive species Late stages of succession, climax Early stages of succession, second growth
Bound to be found by herbivores Protected from herbivores by escape in (cannot escape in time and space) time and space (but still encountered by
wide-ranging generalized herbivores)
Produce more expensive quantitative Produce inexpensive qualitative chemical (broad-based) antiherbivore defenses defenses (poisons or toxins) to discourage (tough leaves, thorns, tannins) generalized herbivores
Quantitative defenses constitute Qualitative defenses may be broken down effective ecological barriers to her- over evolutionary time by coevolution of bivores, although perhaps only a weak appropriate detoxification mechanisms in evolutionary barrier unless supple- herbivores (host plant-specific herbivore mented with qualitative defenses species result)_____________________________________________________________________________
Coevolution: Joint evolution of two (or more) taxa that have close
ecological relationships but do not exchange genes, and in which
reciprocal selective pressures operate to make the evolution of either
taxon partially dependent on the evolution of the other.
Parallel phylogenies: coevolution of pinworms and primate hosts
Drosophila pachea and senita cactus.
Danaid butterflies use polyuridine alkaloids to synthesize pheromones
l-canavanine, present in many legumes ruins protein structure
However, a bruchid beetle has evolved metabolic machinery
that enable it to use plants containing canavanine.
Correlates of plant apparency: quantitative versus qualitative defenses
Coevolution of wild ginger and slug
Antibiotics first discovered in fungi, but also occur in many plants.
Plant secondary chemicals have proven to be a vast reservoir for
useful pharmaceuticals — these include analgesics, diuretics, laxatives,
tranquilizers, contraceptive agents, and cough drops.
Clinically proven drugs derived from higher plants include morphine,
codeine, atropine, quinine, digitalis, and many others. Bark of Pacific
yew trees contains taxol, an effective agent for treating certain ovarian
Cancers (yew genes have been transplanted into bacteria which produce
commercial quantities of taxol in chemostats)
Scientists have only examined about 1 percent of existing plant species
for such useful pharmaceuticals.
Dan JanzenScheelea Palm
Bruchid Beetles
Pine squirrels (Tamiasciurus) andconiferous food trees (Smith 1970)
Squirrels are very effective seed predators, stockpile conesTrees reduce squirrel effectiveness in many different ways:1. Cones difficult for squirrels to reach, open, or carry2. Putting fewer seeds in each cone (fake cones without any seeds)3. Increasing thickness of seed coats (seeds harder to harvest)4. Putting less energy into each seed (smaller seeds)5. Shedding seeds from cones early, before young squirrels forage6. Periodic cone crop failures decimate squirrel populations
Individual trees out of synchrony would set fewer seeds and thusbe selected against.
Christopher Smith
Pharmaceuticalsanalgesicsantibioticsdiureticslaxativestranquilizerscontraceptives taxol (bark of Pacific Yew trees)
Janzen’s seedling ring hypothesis
Coevolution of pine squirrels (Tamiasciurus) and coniferous food trees
Phylogenetics in EcologyPhylogenetic Systematics = Cladistics
Importance of shared derived characteristics (synapomorphies)
Monophyletic groups = Clades
(Polyphyletic, Paraphyletic)
Sister groups, outgroups
Identify ancestral states — polarize character state changes
Phrynosoma
Moloch
Page 343
Evolutionary
Ecomorphology
Convergent Evolution Ecological Equivalents
Monophyletic Paraphyletic Polyphyletic
Phylogenetics in Ecology
Phylogenetic Systematics = Cladistics
Shared derived characteristics (synapomorphies)
Monophyletic vs. Polyphyletic groups
Sister groups, outgroups, rooting trees
Identify ancestral states — polarize character state changes
Minimum Evolution (maximum parsimony) shortest trees
Vicariance Biogeography and Area Cladograms
Phylogeny and the Modern Comparative Method
Phylogenetically Independent Contrasts
Evolutionary Ecomorphology
Convergence (homoplasy)
Willi Hennig
Inferring probable ancestral states
Inferring probable ancestral states
Estimation of ancestral states from those of extant descendents
Ray Huey Al Bennet
Mike Ryan Physolemus Frogs
Phylogenetics in Ecology
Phylogenetic Systematics = Cladistics
Shared derived characteristics (synapomorphies)
Monophyletic groups = Clades
Monophyletic, Polyphyletic, Paraphyletic
Sister groups, outgroups, rooting trees
Identify ancestral states — polarize character state changes
Vicariance Biogeography, Area Cladograms
Phylogeny and the Modern Comparative Method
Phylogenetically Independent Contrasts
Evolutionary Ecomorphology
Convergence (homoplasy)
Vicariance Biogeography
Area Cladograms
Area cladogram for Eublepharid Geckos
Aeluroscalabotes felinus BorneoAluroascalabotes (Borneo)
Goniurosaurus hainanensis, Hainan Island, China
Coleonyx brevis
Coleonyx mitratus
Coleonyx switaki Coleonyx variegatus
Heloderma suspectumHeloderma, North America
Lanthanotus borneensisLanthanotus, Borneo
VaVaranus giganteusVaranus giganteus, Australia
Independent Contrasts
Joe Felsenstein
Independent Contrasts
Joe Felsenstein
Independent Contrasts
Independent Contrasts
Independent Contrasts Pairs
Independent Contrasts Pairs
Independent Contrasts Pairs
Independent Contrasts Pairs