Bsci160 Final

consumption

-+, - interaction in which one organism feeds on another-lethal predation-subleathal predation

what is consumption?

-predation-herbivory-parasitism-predator and prey

consumption has major impact on

-ecology-evolution

ecology

-prey and predator N and distribution-community organization

evolution

-major force of NS

lethal predators exert

-strong selection on prey avoidance

herbivores can be

-generalists or specialists

Ectoparasites often

-transfer between hosts

Endoparasites are often

-species specific, but may have alternate hosts

some plants obtain nutrients

-by being predaceous

N primarily regulated by

-resources -\> bottom up control-predation/disease -\> top down control

Do predators control prey population?

-yes -\> top down population regulation-ex: predator exclusions, and removals-ex: exclosure experiments -\> Dingos and kangaroos on fenced sheep pastures in SE australia

Opuntia strict cactus

-brought from US to australia as ornamental hedge in 1839-by 1925, covered 243,000 km^2-up to 2 m tall, dense spine thickets made rangeland useless

Cactoblastis cactorum

-a moth known to feed on other Opuntia, introduced to argentina in 1914 and 1926-by 1931, the moths had destroyed billions of cacti-since 1940, the cactus persists in low numbers

successful biological control

-not all biological control efforts have such happy endings-moth effecting native cacti in southern US and elsewhere

predator exclusions

-covered plants with mesh during day or night for 10 weeks in colorado island, panama

predator adaptations

-improved detection, capture and processing

reduced capture by

-inc speed-thickening shell-forming groups-getting spiny-by startle-by crypts

reduce predication by

-advertising toxin or venom-aposematic coloration-requires instinct or learning

aposematic coloration

-warning coloration

Bayesian mimicry

-harmless species evolves similarity to harmful/unpalatable species-predation is reduced if predators instinctively avoid pre or if mimic is rare compared to the model and predator learn avoidance

Mullerian mimicry

-Distasteful/harmful species evolve to resemble each other-Monarch and Viceroy butterflies

Mimicry rings result may from predator learning

-both species may suffer low mortality if the predator recognizes them as the same

Helicons mimicry complex

-Heliconius erato and H. melpomene

predator prey interactions lead to adaptations

-prey evolves defenses-predators evolve ways to surmount or tolerate defenses-leas to red queen situation -\> continual coadaptation

plant defensive compounds

-Nitogaen containing-N and Sulfur containing-Phenotics-Terpenes

Mussels and Crabs

-Eurasian Green crab on atlantic coast of N america for 200 years-asian shore crab, \`20 years not yet reached northern maine-young mussels can grow thicker shells in presence of crabs

predation

-+/- integration0important for regulating pop size, community structure and as a force of NS-can but not always control N-predators and prey engage in evolutionary arms race

Parasites

-typically feed on just one or few host individuals

Ectoparasites

-live on surface of host

Endoparasites

live inside their host

Parasitoids

organisms that lay eggs inside other organisms

researchers estimated that

-half the species on earth are parasites

parasite relation ship may be contextual

-varo=ious types of cleaner fish are thought to benefit their hosts by plucking off ectoparasites and the cleaner fish themselves get a nice meal (mutualism)-howeveer when or where these ectoparasites are scarce, the cleaner fish may switch to feeding on scales and muscus from their host as a cost to host (parasitism)

Toxoplasma gondii infection

-latent infection of humans very common

Malaria

-kills hundreds of millions of people each year (sub saran africa and under 5 years old)-related to parasites devastating the native bird fauna of Hawaii (liwi)

deformed frogs and trematodes

-nutrient pollution fuels algal growth-inc pop of snails infected with trematode worm parasite-trematode infects developing frogs causing developmental abdnormalities

human parasites

-internal-external-humans have a lot

Leishmaniasis

-caused by protozoans of genus Leishmania, which are speed by certain biting sandflies

climate change may increase risk of leishmaniasis in North America

-presence of Leishmania protist parasites-presence of appropriate blood sucking sandfly vectors-presence of mammal reservoirs such as neotoma wood rats

parasites have

-major impacts on ecological communities and have enormous medical and economic significance to humans

parasites can

-be generalists or highly specialized even on specific body parts

life cycles are

often complex and can involve hosts of several species

mutualism: barter

- +/+ interaction-widespread and important for ecosystems-major evolutionary consequences

lichens

-fungus and alga or cyanobacterium living together intimately-fungus provide H2o, minerals-algae provide fixed carbon

legume plants and nitrogen fixing bacteria

-mutualistic relationship-legymes develop root nodules harboring nitrogen-fixing bacteria-nitrogen fixation (N2 from air -\> ammonium, which plants use)-plants get N-bacteria get sugars-mutualism -\> major impact on plant growth

plant roots and mycorrhizal fungi

-mycorrhizae-association between fungi and plant root-most plant species

fungi

-help water and mineral uptake (especially phosphorus, nitrogen)-plant contributes sugar and amino acids

ants and acacias

-some ants and acacia tress have close association-ants live in large, hollow thorns0feed on nectar from special nectaries and on modified leaf tips-ants roam over treen defending from herbivores

Acacia ant removal experiments

-bullhorm acacias in central america with ants grew much larger , had higher survival, and experienced less insect herbivory

mutualism has

major evolutionary consequences

community assembly

-species area curves-island biogeography model

community

-all species that interact with each other in a certain area

community structure characterized by

-species number-species abundance-species composition

2 components of species diversity

-species richness-evenness

species richness

-\# species in community

evenness

-relative abdunance of species in community

islands useful

-limited discrete size-relative simple = principles can be evident

larger area =

-more species-greater diversity of habitats-especially for islands more sustainable population sizes (less extinction)

species area curves

-common pattern-species area relationship-number of species vs area-S=cA^z-S = \# species-C= constant-A=area-Z=slope of log plot

empirically

-z values (curve shape) don't vary much -\> typically between 0.15 - 0.35-c values often vary by an order of magnitude or more between archipelagos and taxonomic groups

species area relationship (log)

-log(S) = log (c) +z log (A)

log rul +1

Log (A*B) = log (A) +log (b_

log rule \#2

log (a^b) = blog (A)

island biogeography

-limited discrete size-relatively simple = principles can be evident

theory of island biogeography

-macarthur and wilson-how many species on an isles ? dynamic equilibrium species number-predictions based on colonization and extinction rates

colonization and extinction rates depend on number species already present

-colizination rate dec as \# species present inc (new indie bring species already present)-extinction rate (inc) as \# species present inc (competition, niche overlap inc)

equilibrium species richness

-intersection of colonization and extinction curves-larger islands = more species-more niches-larger population size = lower extinction-inc remote = dec colonization

reduce effect

-species on less remote islands may be less likely to go extinct since more likely to be rescued by immigration

a dynamic equilibrium

-exactly which species are present may change over time

islands

-suitable habitat surrounded by unsuitable habitat

many island chains support predictions

-island size-island remoteness

limitations of dynamic equilibrium model

-does not predict actual species composition-most applicable over intermediate temporal and spatial scales-ignores speculation-ignores geological and climate disturbances-ignores ecological interactions

application of island biogeography and conservation biology

-habitat reserve design-predictions of effects of habitat loss on species richness

which specific species occur in a particular location?

-history matters-ecology matters -\> organisms adapted to particular lifestyle and habitat

many more species at

tropical latitudes

species richness often varies with latitude

-dec from equator to poles in many groups-terrestrial, marine-ex: snakes: canada: 22, US:126, mexico: 293

dominant species

-most abundant or highest biomass

keystone species

-greater effect on other species than abundance and biomass would suggest-often keystone predators-ex: sea otters

humans often

-remove top predators

ecosystem "engineers"

-dramatically alter environment-ex: beavers

disturbance

-event that removed organisms or alters resources availability in community-can impact species diversity and composition-resources become available-biotic and abiotic

intermediate disturbance hypothesis

-low: competitive exclusion-high: slow-colonizing/growing species excluded, abiotic stress-intermediate: tolerances not exceeding for many species, competitive exclusion low-species diversity greatest at moderate levels of disturbance

non equilibrium model:

most communities constantly changing as a result of disturbance

ecosystem

-organisms live in an area plus their physical environemnt

4 components of an ecosystem

-abiotic environment-primary producers-consumers-decomposers
-linked by movement of energy and nutrients

nutrients

building blocks of biological molecules

energy

required to assemble biological molecules

ecosystem processes

-nutrient cycling-energy flow

nutrient cycling

-movement of chemical elements through the ecosystem-recycled

energy flow

-passes one way through ecosystem-cant be recycled (continuous input)

primary production

-sets energy budget for entire ecosystem-spending limit

GPP

-gross primary production-total energy from photosynthesis/area/time-energy from light converted to chemical energy

NPP

-net primary production-NPP=GPP -\> respiration and maintenance of autotrophs-NPP = new biomass made per unit time-energy available to higher trophic levels

Primary production

-NPP measures new biomass, not standing biomass-ecosystem with, high standing biomass can have low NPP-low standing biomass can have high NPP

Pyramids of production

-always wider at bottom

Net primary production

-terrestrial ecosystems-NPP limited by temp, water, sunlight

marine ecosystems

-NPP limited by nutrients and light

productivity per unti area

-g/m^2/yr-\#1 freshwater swamps and marches-\#2 marine algal beds and coral reefs-\#3 tropical rain forests

total productivity

-% total-\#1 open oceans -\> 24%-\#2 tropical rain forests -\> 23%