Guest Lecture 1 Study Questions Exam 2 1 Cogongrass kudzu 2 Fire is the most important thing to keep N Florida pine habitats healthy For some species the fire releases the seeds from their cones Also fire will keep the understory cut back so that young pine trees have the necessary room to grow 3 The Nature Conservancy a conservation organization that works to conserve all lands and waters on which life depends their mission statement In N Florida they are working on restoring the natural pine habitats getting rid of the straight lined pines to make it look like the old habitat from before Europeans settled the area Lecture 16 1 Amphibian decline nearly 32 of amphibians are threated IUCN and this is mainly due to habitat loss Also many species are not even known listed yet and some have very little data on them so it is hard to help a species you know nothing about 2 Confounding when a thing of interest is correlated with something that you don t care about so you can t tell if an effect you measured is due to the thing of interest or the thing you don t care about In the study of native vs conventional landscaping one factor that native plant cover may be confounded with would the plots in the study might not be randomized which would have an effect on caterpillar richness because the study could be biased towards a certain area of the property where by chance the richness was higher 3 4 Mutualism a relationship between two organisms that is beneficial to both Competition a relationship between two organisms in which the fitness of one is lowered by the presence of the other some possible factors are food water territory Predation a relationship between two organisms in which one is the predator and one is the prey and the predator hunts eats the prey Herbivory a relationship between an animal and a plant in which the animal eats the plant Disease a type of symbiotic relationship in which a disease infects an organism and parasitism can be an example of this Indirect effects the impact of the presence or change in abundance of species A on species C via an intermediary species A B C 5 A monarch butterfly caterpillar is a specialist because it only eats milkweeds A specialist is an organism that only eats one or a few types of foods prey or host plants They d be of more conservation concern because it is a lot easier for them to become extinct since they cannot adapt to a changing environment if their primary food was to go extinct A generalist species can change the type of food it eats and adapt to survive 6 Some likely causes of recent declines in monarch butterflies is due to pesticides and a lack of host plants milkweeds for caterpillars and nectar plants for butterflies Also the deforestation in Mexico where they migrate to is a huge problem as well 7 Elaiosome the fleshy structure that is attached to the seeds of certain plants Plants will sometimes have them specifically to attract ants which then take the seed to their nest and therefore it buries the seeds 8 9 Yes the graph shows an interaction between ant species and seed size because it shows that the Anoplolepis prefers the darker bar and the Pheidole prefers the lighter bar which will ultimately have a higher chance of being dispersed 10 Numerical effect when species A directly effects the numbers abundance of species B ex the wolves directly reduce elk numbers by predation Behavioral effect when species A alters the behaviors of species B ex wolves presence makes the elks forage on higher ground as opposed to when there is no wolves the elk forage on lower ground Wolves influence willows in Yellowstone because they prey upon elk The wolves change the behavior of the elk by making them forage on higher ground as opposed to stream valleys and by having the elk increase vigilance and forage less frequently and for shorter times and by overall reducing the elk s population abundance This predation ultimately allows for the willows to grow back in Yellowstone since the elk eat young willows Since the willows are now able to grow back and thrive due to the lessened herbivory by elks this in turn helps many other animals and plants who also had a dependence on the willows Lecture 17 1 One example of how restoring predators helps a lower tropic level is how when the wolves were reintroduced into Yellowstone it helped the Willows because the elk population was reduced which allowed for the willows to thrive make a comeback 2 For the Channel Islands an example of predation is the foxes preying on the mice or the eagles preying on the foxes An example of competition is both the foxes and the skunks are preying on the mice so there is limited food resource An example of an indirect effect is that the eagles prey on only the foxes and the pigs so because the eagles will decrease the numbers of foxes and pigs the skunk population could increase due to less food competition with the fox and less space competition with the pigs and foxes 3 A Two types of management that have been used to help the foxes are 1 trying to get rid of the pigs who outcompete the foxes for space and 2 getting rid of the golden eagles by trying to reintroduce the bald eagles who originally inhabited the islands b One judgment that is involved in management for the island fox is that they wanted to take all of the pigs off the island since they are nonnative and are not necessarily helping any species but since some people think pigs are cute there is uproar over just killing these pigs It would be a good idea since that would reduce the competition for space between the foxes and the pigs 4 Minimum viable population size the smallest number of individuals required for an isolated population to sustain itself Ecologically functional population size populations large enough to maintain their important interactions with other species You d want an ecologically functional population as a target for conservation because this way they have enough of an effect in their environment to perform its niche and not let other species over rule it If you have the bare minimum number of individuals then one little factor could send the whole population extinct if a few individuals died 5 Dominant species the species that are most dominant present in ecosystems that have large effects because they are abundant or have large biomass Keystone species not very high abundance in an ecosystem but they are needed for the system to thrive as a whole They have effects