Week 11 Notes
Popular in Fundamentals of Biology II: Ecology and E
Popular in Biology
This 4 page Class Notes was uploaded by Chasia Notetaker on Thursday April 28, 2016. The Class Notes belongs to BIOL 12000 at Ithaca College taught by Nancy L Jacobson in Fall 2016. Since its upload, it has received 13 views. For similar materials see Fundamentals of Biology II: Ecology and E in Biology at Ithaca College.
Reviews for Week 11 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/28/16
Week of April 11, 2016 Population Momentum = demographic momentum even if every couple has no more than two children population growth will continue for many years happens when a population has been growing rapidly but there is a decrease in reproduction relative to mortality rates because there are already many prereproductive girls alive more than ¼ of the world population is 014 years old (prereproductive) population will continue to increase as the large number of prereproductive females become reproductive Countries are now in different stages of the demographic transition birth rates are high, death rates decreasing (high r) ex. Niger birth rates decreasing, death rates low (positive but lowmoderate r) ex. Mexico birth rates lower than death rates (negative r) ex. Germany Carrying Capacity there are now 7.3 billion people average r=1.1 people added/ people a year ~ 80 million people added each year 910 people by 2050 is probable What is over carrying capacity? ~805 million people are chronically undernourished Asia is the continent with the most hungry peopletwo thirds of the total 209 million people, lower than in 19901992 from 18.711.3 percent globally ~783 million people do not have access to clean drinking water estimated at 114 billion people median 2.15.0 billion depends on number of people and people’s standard of living (level of consumption) improvements in energy and water efficiency how degraded the environment is or becomes One method of determining K ecological footprint area of Earth’s surface required to sustainably support a person at a particular level of development and consumption area that produces resources we need countries are increasing their use of resources as they industrialize Community Ecology Biological Communities assemblages of all the populations of organisms living close together for potential interaction boundaries are hard to place interactions are important (direct and indirect) the structure of a community can be determined by the number and abundance of species a single less abundant species disturbance Interspecific competition two types Interference Competitive exclusion one species excludes the other from an area occurs in two species using the same resource one species will be more efficient at using a resource or it will dominate the other physically thus one species outcompetes and excludes the other Exploitative Resource partitioning allows coexistence (avoids competitive exclusion) species use different subsets of the resource they all need Predation +/ predation benefits the predator population but removes individuals from the prey population predators often evolve better ways to find and capture prey prey evolve better ways to escape being found and captured camouflage may evolve in predators or prey warning coloration and mimicry can evolve in prey to “avoid” being eaten yellow jacket that stings has warning coloration non stinging wasps, beetles, and flies mimic the yellow jacket predators that have experience will avoid Herbivory usually not fatal, but takes energy to repair damage Plant defences have evolved chemical defenses are common (toxins) we often use these as medicine and pesticides salicylic acid (aspirin): from willow bark digitalis (treat certain heart ailments): from foxglove vincristine (treat certain cancers): from periwinkles pyrethrin (insecticide) from chrysanthemums herbivores evolve ways to get around plant defences are specialists some sequester plant toxin and use it as its own defense Parasites and Pathogens live on or in a host which is both its food and home external parasites (ex. ticks and fleas) internal parasites (ex. Flukes, tapeworms, and roundworms) pathogens= microscopic parasites (ex. Viruses, bacteria, fungi, and protists) Mutualism +/ both species benefit hard corals are animals with algae (zooxanthellae) in their tissues coral animals get food (products of photosynthesis algae get a safe place to live in sunlit water and inorganic nutrients mutualism may lead to one or more species becoming dependent on each other they can’t live without each other hard corals are dependent on the algae to provide enough energy to build the large reefs algae will leave the coral if the temperature becomes too high called bleaching if the stress lasts long enough corals will die Indirect Interactions Three level interactions plants>herbivores>carnivores if carnivore population decreases, then allows herbivore population to increase, which causes plant population to decrease interaction between plants and carnivores is indirect Community structure is determined by number and abundance of species species richness (number of species) species evenness (abundance of species)
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'