Population Ecology Presented By Dean Thomas What is

Population Ecology Presented By: Dean Thomas

What is population ecology?

What is population ecology? n n n A population is an assemblage of individuals of the SAME species inhabiting a given area. Ecology is a field of biology that focuses on the interactions between organisms and their environment So population ecology is the dynamics of a species population and how they interact with their environment

What kinds of things do population ecologists look at? n n Population Structure Population Growth

Population Structure n n n Interested in how many individuals make up the population. How are the individuals distributed throughout the environment? Age Structure

Types of Distribution n Clumped Uniform Random http: //www. biology. iupui. edu/biocourses/n 100/images/39 dist. gif

Distribution? http: //io. uwinnipeg. ca/~simmons/16 cm 05/1116/52 -02 a. Clumped. jpg

Distribution? King Penguins on Salisbury Plain – Over 100, 000 Penguins! http: //www. vanda. eclipse. co. uk/travel/Antarctica/images/ Chap_3/Part_3/SP_King_Penguins. jpg

Distribution? http: //io. uwinnipeg. ca/~simmons/16 cm 05/1116/52 -02 cx. Random. Ferns. jpg

What type of distribution pattern do humans show? Why?

Population Growth n n Growth Rate = the percent change in a population over one year Growth rate is affected by ? n ? n

Population Growth n n Growth Rate = the percent change in a population over one year Growth rate is affected by Natality (births) n Mortality (deaths) n Immigration n Emigration n

Growth rate = birth rate – death rate n Let’s try an example A population of 100 rabbits gives birth to 30 rabbits in one year. n 30 births 100 adults =. 30 * 100% = 30% birth rate n If 10 individuals of the 100 rabbits died, what is the death rate? n What is the growth rate of the rabbit population? n

What’s going to happen if this continues? http: //www. beltramiswcd. org/Aquatic%20 Biology/Human%20 Population%20 Growth. jpg

If both of these species became endangered, which has a better chance of rebounding?

Can a population grow forever? n n Animals have the capacity to grow exponentially, but they are limited by resources. What are the four main resources that limit growth?

Can a population grow forever? n n Animals have the capacity to grow exponentially, but they are limited by resources. What are the four main resources that limit growth? n n Food Water Shelter Space

Carrying Capacity n The maximum population that can be supported by an environment Question: What would happen if a population grew beyond their carrying capacity? http: //www. bio. miami. edu/dana/pix/logisticpopns. gif http: //www. geo. arizona. edu/Antevs/nats 104/00 lect 21 grolog. gif

Carrying Capacity n Density-dependent factors

Carrying Capacity n Density-dependent factors n Population-limiting factors that increase as population increases in size Food supplies n Risk of disease in crowded areas n Increase in toxin concentration caused by increased waste levels n n Causes declines in birth or death rates

Carrying Capacity n Density-independent factors n Influences on population rates that are not affected by density Severe drought n Cold winter n n Effects could be worse depending on the size of population

Age Pyramids Which of the two pyramids show a more rapid growing population? What if (a) was inverted?

Let’s look at population ecology at work! Abby Benson - Abby is studying the population ecology and sex-biased dispersal of thirteenlined ground squirrels in and out of prairie dog colonies in northern Colorado. Her research is also part of the broader NSF-funded plague project underway in northern Colorado. http: //faculty. fullerton. edu/pstapp/IMG_324 5. jpg

How do we estimate populations when we don’t have census data? n n It’s hard to count every individual and can be very time consuming! If the critters are mobile, they are probably sneaky and don’t want to be found. Makes your job a little harder.

Examples of population survey techniques n Plot sampling (Quadrat sampling) n n Estimate density Estimate percent cover What types of organisms is this method good for? What would it not work for? http: //lh 6. ggpht. com/_vg. CJNd. Zc. Gw 8/SGf. KBHgu. Bd. I/AAAA AOg/y. QIYwu. H 6 g 8 c/Spellman. Ecolab_Stephanie%26 Me_plots. jpg

Examples of population survey techniques n Mark-Recapture Sampling Capture n Mark all that you captured n Release n Recapture n Estimate population by the ratio of marked to unmarked n

Examples of population survey techniques n n Mark-Recapture Sampling Equation: N/M = n/R N = Estimated Population n M = Marked individuals n n = number of individuals in the second sample n R = Recaptured individuals n So, N = Mn/R n

Examples of population survey techniques n Mark-Recapture Sampling n An example

Mark-Recapture Sampling in Action! Still Creek Fish Trap, Mt. Hood, OR

Mark-Recapture Sampling in Action! Still Creek Fish Trap, Mt. Hood, OR Can you find the marked fish?

Mark-Recapture Sampling in Action! Still Creek Fish Trap, Mt. Hood, OR

Mark-Recapture Sampling in Action! Still Creek Fish Trap, Mt. Hood, OR Back to the office to analyze the data!

Link to recent Hudson River plane crash http: //www. cnn. com/2009/US/01/15/hudson. plane. videos/index. html

http: //img. photobucket. com/albums/v 442/iftk/10/planer_vs_plane_001. j pg

http: //www. dontdumponwilliston. org/images/bird-v-plane. jpg

http: //img. photobucket. com/albums/v 442/iftk/10/planer_vs_plane_002. jpg

Where does population ecology come into play with the dangers of bird strikes? Well, lets be wildlife biologists and take a look!