DOC PREVIEW
UMass Amherst BIOLOGY 152 - Beginning of Community Ecology

This preview shows page 1 out of 4 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 4 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 4 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Lecture 30BIOLOGY 152 1st Edition Lecture 30Outline of Last Lecturei. Exponential Growth Model continued b. What Limits Population Growth? c. Experiment on Intrinsic Factors Outline of Current LectureII. Age structuring and reproductivestrategies a. Survivorship Curves III. Community Ecology a. Niches and Definitions Current LectureAge structuring and reproductive strategies- numbers alone do not tell you everything about the health of a population - will have different ages — so age structure pyramids can tell youwhether a population is likely to be stable, is growing or may begetting ready to shrink - important to know what age they breed at (deers breed later in lifethan quails do), this can help you understand where the population isgoing **Clicker Question**The age structure of a population can tell you whether it is likely to be growing or not. Which of these is poised to grow most rapidly? **shows image with age structure pyramid from afghanistan, US and Italy- answer = Afghanistan (based on this data alone) - have many people in the youngest group, and if they live they willmove on to their prime reproductive years - the US population is stable — not growing, maintaining - in Italy the population is shrinking — will get a smaller reproductivepopulation in a few years *also important to look at survival rates as wellLooking at Atlantic cod, you have 3 different estimates showing egg production. Fish grow as they age. If we catch the bigger fish how arewe affecting the population’s growth expectancy?- larger fish lay more eggs but we weren’t given any information aboutthe numbers of fish - the effect of this will be to deplete the population — if you cut off theones that are at their prime breeding age then you’re lowering thenumber of eggs put into the environment, lower numbers going to befertilized and so a lower population (population will shrink) - answer = D Species have different “survivorship curves”- the likelihood that a single offspring will survive to adulthood isdifferent for different organisms - some organisms young are very susceptible to death — many plants,baby turtles, fish - some have evenly distributed death rates (birds and small mammals) - some often survive a long time (usually big animals) - these survivorship curves affect reproductive strategies — amount ofeffort they put into their offspring - 2 stretegies = r and K strategies r strategists = trying to make as many babies as possible, want to make sure their per capita are very highex: a dandelion puts out thousands of seeds, most of which are going to land where they can’t grow, others might get eaten etc.K strategists = raise just a few young and put a lot of energy into those few young, live very close to the carrying capacityex: Peregrine falcon, they lay just enough to maintain at a certain levelIs a bobwhite quail or a white-tailed deer more likely to be an r strategist?- the bobwhite — they tend to lay around 16 eggs, a game and a preyspecies and are likely to die younger TL;DLPrairie dog videoCommunity Ecology Niches and Definitionsbiological community = the collection of species that occur at a givenlocality — only living organisms- interactions among these organisms define this community - can vary by size: ex: a gut (bacteria infeces) - tree- forest - ecosystems include the abiotic parts (the rocks, the climate, etc.) - within biological community all organisms have niches - Niche = total of all the ways an organism uses the environment, no twoorganisms can inhabit the exact same niche - the way the birds in the image split up the resource is calledresource partitioning - ecosystem is divided up into different niches Experiment — one species of barnacle was removed from the rocks. Which part is the niche for the one left behind?- both the upper and lower part of the rock - the bottom one = the fundamental niche — the space that theycould inhabit if they didn’t have the other barnacle species there - the top one = the realized niche — what they actually inhabit giventhe space they have available **this is an example of resource partitioning — the resource(rock) has been divided up so that both organisms can live in thesame area peacefully Which of the following best describes resource partitioning?- slight variations in niche that allow similar organisms to coexist**Clicker Question**These data show pop density for 2 different species of paramecium grown in culture for three weeks. They both eat bacteria. What COULDhappen if you were to mix them?- one paramecium species dies out - they split the culture into two parts so neither grows quite as well - if they both reached K faster that means that r is faster, so D can’t betrue *what actually happens is that one of the parameciumoutcompetes the other = competitive exclusion What might explain the data seen with these two species of paramecia?- resource partitioning - the two organisms have been grown together, they’re both stillpresent but neither of them is growing as fast as they did before - they have taken the resource and have split it up in some way — when they’re alone they spread out to their fundamental niche, however whenplaced together they both are contained to their realized niches Can also split them up by time- golden spiny mouse and common spiny mouse : one is diurnal and oneis nocturnalHave a healthy micro biome because of competitive exclusion but antibiotics threaten this- now we give people even stronger antibiotics which works sometimes butoften you have recurrence - one of the best ways to deal with this is to give people macrobiotic transplantation (fecal transplant)— take poop from one person, give it to another person and bacteria recolonize their gut - data shown from different studies - resolution = how many people got better, which in this is very highcompared to relapses - fecal transplantation is proving to be a much better way of dealingwith this


View Full Document

UMass Amherst BIOLOGY 152 - Beginning of Community Ecology

Documents in this Course
Load more
Download Beginning of Community Ecology
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Beginning of Community Ecology and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Beginning of Community Ecology 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?