Herbivory

tritrophic interactions

Occur when a change at one trophic level indirectly affects trophic levels which are more than one step away.

bottom-up control

The abundance of predator populations at higher trophic levels is regulated by the abundance of prey populations at lower trophic levels

top-down control

The abundance of prey populations at lower trophic levels is regulated by the abundance of predator populations at higher trophic levels

induced defenses in plants

a defensive structure or compound that is produced in response to herbivory or predation

filter feeding

a method of feeding in which the animal traps organic material that is floating in the surrounding water

evolutionary arms race

adaptation in one lineage may change selection pressure on another lineage, giving rise to counter-adaptation

bottom-up control example

algal bloom-a nutrient runoff occurs that causes a large increase in the algal population

economic impacts of herbivory in forest

beetles bore into trees and kill them a. leads to were usable trees and causes gaps in forest canopy b. costs billions of dollars from lost forest products, reforestation management, and the removal/disposal of hazard trees

economic impacts of herbivory in crops

cost to control pest and the cost of crops lost is over a billion dollars

seed coat

increased seed coat density increases a herbivore's energetic costs of acquiring the nutritious endosperm

browsing

involves feeding on leaves, shoots, and fruits that are higher off the ground

herbivory

process in which animal consumes plant or plant-like substance

costs of induced defense

resource allocation leads to tradeoff in plant growth and development

herbivore biocontrol

the introduction of non-native control agents into region to permanently suppress the population of selected target plants

ethnobotany

the study of how people of a particular culture and region make use of indigenous plants

defensive secondary metabolites

used by plants to defend against herbivores, pathogens, and parasites

top-down control example

1 kelp forest ecosystem 2. sea otters are a keystone predator that preys on urchins. 3. the urchins eat kelp 4. when urchins are eaten, kelp can grow

ecological effects of herbivores

1. reduce plant fitness 2. reduce plant growth rate and reproductive output 3. control plant abundance and distribution 4. alter plant community structure and composition

mangrove climate change case study

1. relative sea level rise causes mangroves to retreat landward due to tree dieback 2. results in loss of biodiversity

effects of climate change on herbivores

1. shifted range for herbivores 2. leads to agricultural changes-deforestation in some ares 3. pathogen will have range shifts-new health risks 4. humans will have to adjust disease control

specialist vs. generalist

1. specialists have small, local distribution in which they have co-evolved with plants they eat 2. generalists have large geographic distribution

burrowing

1. the method of animals burrowing into their food while eating out a tunnel as the move 2. creates a shelter while they eat

herbivore limited plant communities ecosystem

1. top-down control 2. predator control 3. invasive species

qualitative chemical plant defense

1. toxic compounds that can deter feeding or affect herbivores after ingestion of small doses 2. nightshade 3. concentrations in leaves are constant and small 4. common in short-lived plants 5. low cost-easy counter adaptation by specialists 6. alkaloids

mechanical plant defense

1. use of physical defenses to dissuade or limit a herbivore's feeding ability 2. thorns, spines, glandular trichomes, seed coats

chemical plant defense

1. use of secondary metabolites for herbivore defense 2. alkaloids, terpenoids

example of evolutionary arms race in corn ear worm and tobacco

1. plant adaptation: increase in nicotine production 2. herbivore counter-adaptation: pest has developed enzyme in saliva that counteracts plant's defense

quantitative chemical plant defense

1. Substances eaten in large amount by herbivores that impede digestion 2. dosage dependent 3. common in long-lived plants 4. high cost-difficult counteradaptation

benefits of induced defense

1. reduce chance of herbivore adapting to plant defense 2. reduce metabolic load on plant in condition where biological chemicals are unnecessary

flora and fauna response to climate change

1. adapt 2. migrate 3. die

burrowing examples

1. bark beetles 2. leaf miners 3. termites

bark beetles and climate change

1. beetles have temperature-dependent life-history strategies 2. climate change will affect outbreaks, increasing frequency and intensity 3. coniferous forests most affected

resource limited plant communities ecosystem

1. bottom-up control 2. natural resources like light, minerals, water, carbon dioxide control plant communities

what can go wrong with biocontrols?

1. can fail to become established 2. do not have impact on target species 3. attack on non-target hosts 4. could spread unforeseen disease or pathogens

economic impacts of herbivory via overgrazing

1. causes soil degradation that lowers future crop yield 2. may lead to mass desertification

effects of climate change in arctic marine environments

1. change in primary productivity 2. shift of species range 3. redistribution of species 4. species turnover 5. increase in disease and extinctions

grazing examples

1. cows 2. grasshoppers 3. rodents

example of induced defense in plants

1. defense transcription products in potato leaves 2. occurred more rapidly when leaves were chewed by caterpillars 3. signal transduction pathways were activated in response to insect herbivory

glucosinolates

1. defensive secondary metabolite produced by plant 2. beneficial to humans as possible cancer inhibitor for many organ systems 3. found in high quantities in broccoli, brussels sprouts, and cabbage

phenylpropanoid

1. defensive secondary metabolite produced by plant 2. can protect against UV rays 3. helps heal wounds

flavonoids

1. defensive secondary metabolite produced in plant 2. acts as UV protection and defense against pathogens in plants 3. provides antioxidants to humans that help protect against disease

why is earth green with all these herbivores

1. density-dependent mechanisms prevents predators from reaching certain pop. levels. can't eat all available plants 2. plants defend themselves 3. plants limited by resource availability

frugivore

1. eat fruit 2. lemur

folivore

1. eat leaves 2. koala

nectarivore

1. eat nectar 2. honey possum

granivore

1. eat seeds 2. honeycreepers

grazing

1. eating grasses and other small plants from the surface of the ground 2. includes scraping algae from surface of water 3. does not provide animals with many nutrients

mucivore

1. feed on plant liquid 2. aphids

palynivore

1. feed on pollen 2. honeybee

xylophage

1. feed on wood 2. termite

herbivory importance in food webs

1. foundation of food web 2. reflection of plant species diversity and abundance

browsing examples

1. goats 2. caterpillars 3. panda

limiting factors to plants

1. herbivores 2. resources 3. depends what environment plant is in (top-down control or bottom-up control)

types of plant defense against herbivores

1. mechanical 2. chemical

example of herbivores that co-opted defense of host plants for their own protection

1. myrmecophyte: plant that live in mutualistic association with ant colony. protect ants that protect acacias 2. plant structural adaptation: domatia, food bodies 3. ant aid: pollination, seed dispersal, defense

evolution of increased competitive ability

1. non-native plants subject to decreased herbivory because they aren't in contact with natural enemies 2 .plants evolve increased competitive ability because they reallocate resources from defense mechanisms into growth, development, and fitness gains

specialist

1. organisms that feed on one or a few closely related food species 2. most are able to consume plants with chemical or physical defenses 3. gain most to all nutrients needed to survive from one food source 4. stenaphogous

generalist

1. organisms that feed on several non-related plant species 2. euryphagous

filter feeding examples

1. oysters 2. barnacles 3. flamingos