Sponge: Set up Cornell Notes on pg. 15 Topic: 5.3 Populations Essential Question: Two centuries ago, there were only one billion people on Earth. Today, over 6 billion. Which phase of the s- curve are we in? BIOZONE: None LAB REPORT DUE FRIDAY!!!! 5.3 Populations BIOZONE: None Key Vocabulary: Natality Mortality Immigration Emigration S-shaped curve Exponential phase Transitional Phase Plateau Phase Carrying Capacity Two centuries ago, there were only one billion people on Earth. Today, over 6 billion. Which phase of the s- curve are we in?

P. 14Natality Mortality Immigration Emigration PICTURES S-shaped Curve

Mt. St. Helens Clip 6m30s

Mount Saint Helens Eruption 1980 Little was left of the forest and rivers Trees were knocked over Fires/gases/Volcanic Ash burned everything Even though the mountain was evacuated, some people who did not leave in time perished

Within months, LIFE WAS BACK Within a couple of decades… a grassland ecosystem has reappeared

Population Growth Curve After an event that wipes out most life (Mt. St. Helens), there can be a dramatic increase in population #s Eventually a complete forest will grow again, and all habitats will be occupied The numbers of organisms will stabilize and not get any bigger

Assessment Statement Outline how population size is affected by natality, immigration, mortality, and emigration.

4 main factors affect population size 1. Natality- the # of new members of the species due to reproduction 2. Mortality- the # of deaths Draw pictures that represent each P. 14

3. Immigration- members arriving from other places 4. Emigration- members leaving the population Draw pictures that represent each P. 14

Assessment Statement List three factors that set limits to population increase

Carrying Capacity The maximum # of individuals that a particular habitat can support is called the carrying capacity No habitat can accommodate an unlimited number of organisms

White Boards!!! Get Your Whiteboards!!!! What are some factors that would LIMIT the carrying capacity of a habitat?

Limiting Factors Availability of resources: water food sunlight shelter space oxygen Build up of waste such as excrement or excess CO2 Predation Disease

S-shaped Curve Exponential Growth Phase Transitional Phase Plateau Phase Bottom ½ of p. 15

Assessment Statement Draw and label a graph showing a sigmoid (S- shaped) population growth curve Explain the reasons for the exponential growth phase, the plateau phase and the transitional phase between these two phases

The Sigmoid (s-Shaped) Curve

1. Exponential Growth Phase (logarithmic phase): the numbers of individuals increases at a faster and faster rate 2. Transitional phase: the growth rate slows down considerably- the population is still increasing but at a slower and slower rate 3. The Plateau Phase (Stationary phase): the number of individuals has stabilized- there is no more growth

Exponential Phase In ideal conditions, a population can double on a regular basis (not counting mortality) Without predators, an introduced species can take over habitats with uncontrolled population growth Why? (Whiteboards) Plentiful resources (space/food/light) Little or no competition Favorable abiotic factors (temp/oxy levels) Little or no predation or disease

Transitional Phase What will begin to happen as growth rate continues to increase? Eventually, some of the previously listed factors above will no longer be true As population number increases, competition increases Predators will be attracted to a growing food supply and move in As numbers increase, and crowding occur, diseases begin to spread

Plateau Phase Once all the fertile ground is covered with plants the space available will be occupied to its maximum (less available room for seeds) With increasing #s of herbivores, there will be a limited supply of food (in response animals have less offspring) Predators and disease increase mortality rate Growth curve tends to level off Births + Immigration = Deaths + Emigration

Carrying Capacity Draw on the bottom of P. 14 s-Shaped Curve

Population Biology The Effect of Predators on Prey Populations

Too Many Deer

Sponge: Set up Cornell Notes on pg. 17 Topic: G1/G3/5.3 Estimating Populations Essential Question: BIOZONE: LAB REPORT DUE TOMORROW!!!! G1/G3/5.3 Estimating Populations BIOZONE: Key Vocabulary: Random Sampling Quadrat Method Transect Technique Capture-Mark-Release-Recapture Method BRING BIOZONES ON MONDAY

Assessment Statement G.1.3 Describe one method of random sampling, based on quadrat methods, that is used to compare the population size of two plant or two animal species

Random Sampling How can we determine population numbers? We could go count every pine tree in a forest, but that would be too time consuming Ecologists instead use a sampling method They take a “random sample” and use it to estimate the total number of organisms Samples should come from all around the habitat

Quadrat Method The quadrat is a square of a certain size Organisms within the quadrat are counted and these counts are used to determine the population size of a given area They can be small or large depending on what you are counting

Method Summary Map an entire area of the tide pools Determine the size of the quadrats Place a grid with numbers over the map of the tide pool area Choose which squares to sample using a random number table Count the number of starfish in each sample quadrat Calculate the average # of starfish in your sample quadrats Multiply the average by the total number of quadrats on your map to get an estimate of the total number of starfish in the tide pools

Assessment Statement G.1.4 Outline the use of a transect to correlate the distribution of plant or animal species with an abiotic variable

The Transect Technique Commonly used for studying how the distribution of plants in an ecosystem is affected by abiotic factors At right angles, lay tape all the way around your chosen ecosystem Every meters along the tape, mark out a quadrat always using the same size Identify and count the plant species of interest in each quadrat Measure the abiotic feature that you have chosen in each quadrat (temp/light/soil pH/water/mineral nutrients) You can now determine the pattern of distribution of plant species from different areas of the ecosystem and see if it correlates with the abiotic factor you chose

Quadrat Activity: How Many Sunflowers in a Meadow?

LAB REPORTS DUE Make sure your name/period # is clearly written Stapled? PLEASE ATTACH DATA COLLECTION SHEET!!!!

Assessment Statement G.5.3 Describe one technique used to estimate the population size of an animal species based on a mark- release-recapture method

Capture-Mark-Release-Recapture Method Allows you to estimate the # of animals in an ecosystem Catch some of the population Mark them, and release them back into the wild A second sample of the population is captured Some will be marked, some will be unmarked The thought: the proportion of marked to unmarked individuals in the second sample is the same as the proportion of the originally marked individuals to the whole population # marked in the 2 nd sample (n3) = # marked in the 1 st sample (n1) total # caught in 2 nd sample (n2) size of the whole population

Capture-Mark-Release-Recapture Limitations Marks may injure animals Marks may make animals more visible to predators Method assumes there is no immigration/emigration Let’s try it!!!!