Population Ecology powerpoint with invasive

Population ecology

1. What is a Population? A group of organisms of the same species living in the same place at the same time Compete with each other & amongst other populations for resources Numbers will go up and down continuously How many different populations are shown here? 3

2. Change in Population Size Population Increase : caused by births and immigration Population Decrease : caused by deaths and emigration Population = B + I –D - E There is a population of 500 birds. In one year, 160 birds were born, 130 birds died, 40 individuals immigrated and 20 emigrated this way. Set-up the math on how to find the current population. 500+160-130+40-20 = 550

3. There are two population growth graphs you must know…

4. Putting some individuals in an area for the first time where they have no competition, plentiful resources and no predators This will cause their population to grow rapidly at an ever-increasing rate (doubling over same time intervals) Every generation, this population of bacteria doubles! J 1. Exponential Growth (J Curve)

5. Why is this island chock full of rabbits? BBC Why were these rabbits able to grow exponentially? What factors could limit their population size? I can’t add or subtract, but I can multiply!

6. A plant or animal that is non-native to a specific location (an introduced species) Because evolution has not created a balanced/restricted niche for this species, it may: Have no predators Have little competition Results include: Exponential growth Decline of native species Invasive Species

7. Biotic Potential Maximum reproduction rate of a population in ideal conditions Biotic potential is more theoretical In reality, eventually populations will be limited by abiotic (non-living) and/or biotic (living) factors

8. Limiting Factors : limit the population size from reaching its biotic potential Density-Dependent These factors have an increasing effect as the population increases. ex. food, disease, predators, space, competition Density-Independent These factors can affect populations, regardless of their density Ex. temperature, storms, floods, droughts

9. What is the biotic potential of this corn? What factor limits the growth of this corn the most? 60cm Lack of Moisture Is “Poor Soil Structure ” Density-Dependent or Density-Independent? How about “Insects & Diseases?” I D YOU TRY!

10. What could these populations be competing for? Space Food Mates Light Which two are abiotic? Which two are biotic? Competition Competition is a density-dependent limiting factor Occurs because resources are limiting in the environment (demand is greater than supply)

11. 2. Logistic Growth Curve (S-curve) Starts off as a “J” curve, but then limiting factors begin reducing rate of population growth Eventually, population reaches carrying capacity (K) the maximum population size that an environment can support. Where the line levels out OVER TIME What is the carrying capacity for this population? Point of inflection where population growth rate slows 7500 S

12. What is the carrying capacity? What is the overshoot & why does it happen? Why isn’t the carrying capacity a straight line? When carrying capacity exceeded due to  reproductive time lag 75-80 The # of births & immigration would have to equal the # of deaths & emigration Yeeeahhh , not likely, mate

13. Predator-Prey Relationships The predators and the prey keep each other’s populations in check If the predator is lost, this can lead to a trophic cascade

14. Important Species WHAT IF I TOLD YOU SOME SPECIES ARE MORE IMPORTANT THAN OTHERS

15. Case Study: The Grey Wolf, Yellowstone Trophic Cascade : removal of top predators resulting in reciprocal changes in other populations due to the interconnectedness of food webs, which often results in dramatic changes in ecosystem structure and nutrient cycling

16. Keystone Species A species that, if removed, results in the health of an ecosystem drastically declining.

17. Why would scientists study otter populations?

18. Ecosystem Engineers Species that modify their environment in such a way that other organisms rely on the changes to live or thrive Also keystone species

19. Indicator Species Species that are very sensitive to a certain environmental condition Their presence, absence, or health is affected more than the other species in the environment, thus, ecologists can use them as an indicator of the health and well-being of an ecosystem

20. Population Bottleneck A drastic reduction in population size This greatly reduces genetic diversity, making this population more susceptible to diseases and extinction This isn’t going to be good

21. If both of these populations were to be bottlenecked, which population would have an easier time recovering? Why?

22. The finches have reached a “balance” with the ecosystem, with about the same numbers of births as there are deaths from year to year. A few finches have blown over to the island in a storm. They find there is plenty of food to go around are happily live and begin to breed. Eventually they run out of food and nesting grounds (limiting factors kick in) and so their population numbers begin to slow. The finches population explodes exponentially as the bounty of the island keeps on giving! Look at the red tick marks on the graph. They are in increments of 5. What is the carrying capacity of the finches on the island? This type of population growth is called l ogistic or e xponential? The following graph depicts a population of finches on an island overtime. Match the following statement about the finches with the correct phase on the graph. Bell Ringer To get your numbers, find the animal associated with the letter. How many letter are in that animals name? Ex. A = Alligator =9. Then add all the numbers together

23. Population Ecology Is weather a density- d ependent or density- i ndependent factor? Do invasive species exhibit e xponential or l ogistic growth? Is the populations of predators or prey a density- d ependent or density- i ndependent factor? A long-term stable population growth would be a “ J ” shape or a “ S ” shape? There is a lake with 80 frogs in it. Over the course of the year, lots of tadpoles were born but only 28 made it to adulthood. Also, 14 of the existing adult frogs died. 4 frogs immigrated from a nearby pond and 9 emigrated. What is the population of frogs? How many more frogs are there this year compared to last year? CODE

24. Alternative Bell Ringer Four Daphnia were placed in a water tank and fed the same amount of food twice a day. Their population density was recorded. 1. What is the carrying capacity of Daphnia? 2. How many days after introducing the daphnia into the tank did limiting factors begin to play a role in their population density?