ECOL 182R 1st Edition Lecture 19 Outline of Last Lecture I Black carbon tropospheric ozone II Politically controversial III IPCC reports A Positive negative IV Coral reefs V Predicted impacts VI Prediction rates compared to the past A Major extinction Outline of Current Lecture I Interactions between species II Cooperation and mutualism III Mutualistic exchanges IV Mutualisms have costs V Why cooperate Current Lecture Interspecific interactions Interaction between 2 species can Benefit Harm No effect 0 on each of them Competition is a interaction because both species do worse when together Ex Different species fighting over food Commensalism is a 0 interaction because one does better when together the other is unaffected Ex Clownfish in anemone Amensalism is a 0 interaction because one does worse the other is unaffected Ex Humans and roadkill Antagonism is a reaction because one does worse and the other does better 1 Predation killing eating of prey by predator 2 Herbivory partial consumption of plants by animals 3 Parasitism partial consumption of animals by animals Endoparasite lives inside host doesn t eat all of you Ectoparasite feeds from outside of host Ticks mites fleas lice 4 Pathogens microorganisms living reproducing inside hosts causing disease Mutualism is a interaction because both species do better when they re together Ex Hummingbird pollinating flowers Cooperation is a broad term that pretty much means beneficial interactions among anyone But mutualism is specifically between two species Ex Bees in a hive cooperation same species Similarities between mutualism is cooperation 1 Both participants benefit 2 Conflicts exist 3 Cheating is everywhere In mutualism partners usually exchange different things altruism is not a possibility Mutualism isn t nice or generous They aren t doing it for the other species Each is using its mutualist to survive and reproduce Animal pollination mutualism Yuccas can only be pollinated by Yucca Moths Yucca Moths can only reproduce on yuccas Seed dispersal mutualism Animal gets food tree gets planted Protection mutualism Ants get food from caterpillars nutritional secretion and caterpillars are protected Nutritional mutualism In roots of bean plants the plant gets nutrients that bacteria rhizobium in nodules are providing and the bacteria are getting protected This is a symbiotic mutualism partners are physiologically integrated Other ways Mutualism can be divided up Highly specialized to loosely generalized Obligate neither reproduced without the other species specific the Yucca example Highly specialized Datura and hawkmoths There s a group that can all visit these flowers but still not a lot More generalized Manzanita and insects There s a huge diversity of insects that can visit the flowers Extremely generalized Mutualisms have costs too Mutualisms are best known for the benefits they confer But there are definitely costs Ex Yuccas lose good seeds to their pollinators offspring Ex Plants insects invest water nutrients into rewards for ant defenders Ex Plants invest water nutrients into rewards for pollinators seed dispersers Then why engage in mutualism at all Traits that benefit one partner only will not persist BOTH must benefit Mutualists do best when they maximize benefits minimize costs of interacting Ex In pollination the plant benefits from pollen transfer but the cost is making nectar flashy flowers The pollinator gets food but gives time energy searching Each plant makes less nectar than what the pollinator needs so pollinator has to leave and get more good for plant not animal And pollinators switch plant species if there s more nectar elsewhere majoring and minoring which is only good for the pollinator Proves that mutualism IS NOT generosity There are conflicts of interest Wherever there s cooperation there s cheating Nectar robbing poking hole to access nectar Feeds but bypasses pollen Nectar less flowers mixed with nectar flowers butterflies fall for it so they get pollinated even though they aren t giving nectar Pseudocopulation Nectar less flower smells like a female male wasps visit and attempts to mate gets pollen all over it and gets frustrated Flower benefits wasp gets mad
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