BIOL 2140 Exam # 2 Study Guide Lectures: 1-11Lecture 1 (September 29)Natural selection toothpick exercise - The toothpick colors had an impact in survival and extinction. - Dark color toothpicks blended better than brighter colored toothpicks that stood out *color (outside of photosynthesis) is a result of community interactions In a simple community (like the toothpick experiment) the best camouflaging species survives while every other species is wiped outIn a complex community other factors are involved through a greater interaction. Lecture 2 (October 1) Communities Crypsis: coloration/form of camouflageEx. Sharks use countershading where their dark backs blend with dark ocean floor from above and their light bellies blend with the light from below. Disruptive coloration: zebras are not necessarily camouflaging but when together in a group the color becomes a blur for predators to focus and pick one out. Warning coloration: (aposematism) advertise danger. Species with this adaptation develop bright and noticeable traits that warn predators not to come near, ex. Poisonous frogs. Predators learn not to go after bright colored frogs from learned experience. Mimicry: imitate something else for own benefit. We tend to associate bright color with danger (poisonous) some species develop these characteristics as a survival mechanism even if they don’t pose any harm. This is specifically called batesian, where a harmless species looks dangerous, and gets a “free ride” in survival. Ex. Beetle with bright yellow back is likely to fool birds and therefore prevent being eaten. Müllerian: harmful species that look similar use their characteristics to reinforce their danger. Ex. Both bees and wasps have stripes that are well known to cause danger, associating both reinforces to keep away. Other: sometimes animals are able to develop traits that lure prey and keep predators away. Ex. Moths with eyespots tend to scare predators, predators feel less effective if they are “seen” Ex.2 wild orchids trick bees into pollinating them Selective pressure: are linked among communities, the response of one species triggers the response of another and vice versa.-plant develops thorns to prevent being eaten, predator then develops stronger teeth/mouth, plant then develops even stronger thorns -plant can also develop poison, predator will develop an immunity Yucca moth example: the yucca plant depends on the moth for pollination, and the moth consumes part of the plant and uses the plant as a home to lay eggs, but if too many eggs arelaid they will hurt plant, therefore plant can commit suicide which then prevents eggs from developing, so yucca moths learned to lay less eggs to remain in a mutual benefit. Coevolution: Must be a direct, reciprocal adaptive responseLecture 3 (October 3) Animal interactionsThe lion vs buffalo example: the buffalo had an advantage due to larger size, horns, and herd. Not only were there physical advantages but also behavioral such as adults working together to rescue the young. Animal relationships can fall into more than one category. Mutualism: both benefitCommensalism: one benefits while the other neither benefits or is harmed Consumer-resource: one consumes benefit at expense of other -Predation: one organism eats another, killing it-Parasitism: one organism feeds on another, without killing it- Parasitoidism: one organism feeds on another slowly like a parasite, but fatally so—eventually DOES kill it but slowly over timeamensalism: harm one another without one really benefiting Competition: compete for same source (hurt both) Do we need mosquitos? Mosquitos alter caribou migration which has a bigger effect on populations. Major disease can result (west Nile). Can have a varying effect. Lecture 4 (October 6) Would you eat a hippo? Humans faced a meat drought and it was suggested to extract energy from hippos as a food source. Invasive species: can happen naturally or be brought up by humans, this is called introduced species The impact of new species can be unpredictable cause strong selective pressures. Fundamental vs realized niche. Realized niche may shift in new environment. Example: flightless birds in Hawaii were easy targets for rats and cats that came along with colonization this led to their extinction. Lecture 5 (October 8) Fire ants: native vs nonnative fireants. Native fireants may be able to control invader fire ants. Toads control fire ants but not invader fire ants. Congress grass grow thick roots and strain otherplants from growing. Zebra mussels, overpopulate outcompete other species. Species interactions: ecological succession, success of one species can be influenced by the impact of others develops from a new naked habitat to a mature one. One species (weeds) grow1st and allow 2nd species (trees) to grow. Or humans can damage environment, walking on grass prevents grass growth and creates a pathway. Pioneer species are able to grow in difficult conditions. (Growth on rocks in a dry lake) Facilitation: early species pave the way for next species Inhibition: early species block the way for next speciesPatterns may be short live or periodic, short lived ( vernal pool) last longer, more stable The lotka-volterra model: Prey: dV/dt = rV – cVPPredator: dP/dt = bcVP –mP Predation rate is a function of capture efficiency along with both prey and predator abundancesLecture 6 (October 10) Paired population dynamics Predator-prey curve isn’t linear, the population is dynamicType 1: prey and feeding increase proportionately (linear, but nonrealistic) Type 2: prey and feeding increase only to a satiation point. Type 3: prey and feeding increase to a satiation after a learning curve (artichokes example, because there is an abundance of it tend to lead to a new food source. Why don’t predators catch all prey? Sometimes they do leads to extinction In stable situations they don’t, can be physically impossible to catch all prey. Prey refugee- multiple habitats, animals can hide. Allows population to continue Giant kelp in coast- very photosynthetic, other animals’ benefit (snails consume). Sea urchins would then wipe out kelp, but you don’t just lose the kelp you lose everything else associated with kelp. Form urchin barrens. Sea otters consume sea urchins which indirectly protect the kelp. But the reason there was a lot of sea urchins is because the otters were being removed from the habitat thus causing an imbalance. Sea