Finish Your Levels of Organization Pyramid: Remember each Layer is based on size

Quiz 1.What basic needs are provided by an organisms habitat? 2.List these terms in order from smallest unit to largest: Population, organism, ecosystem, community 3. Why do ecologist study biotic and abiotic factors in an ecosystem. 4. Would all the insects of a forest be consisdered a population? Why / why not? 5. List two abiotic factors?

Populations

Fold your paper “hotdog” Right to left Direct Observation Indirect Observation Sampling Mark and Recapture Studies

Direct Observation Most obvious means of determining size is to count one by one.

Indirect Observation ~ Sometimes organisms are too small or too hard to find. ~ Observing their tracks or other signs rather than counting.

Sampling Most cases there are too many organisms in an are to count. Take a set area, estimate the number in the area and multiply by the number of areas. Count 8 red maples in a 10 meter by-10-meter area of the forest. If the entire forest were 100x that size, you would mulitply your count by 100 to estimate total population, 800 red maples.

Mark and recapture Catch a group of animals – tag them Catch a second group of animals –tag them

Changes In Population Size

Births and Deaths Population Equation Immigration and Emigration Graphing Changes in Population

Populations can change in size when new members enter the population or when members leave the population

Births and Deaths Birth rate of a population is the number of births in a population in a certain amount of time. Death rate is the number of deaths in a certain amount of time.

The population Equation If birth rate > death rate, population size increases If death rate is > birth rate, population size decreases

Immigration and emigration Immigration means moving into a population Emigration means leaving a population

Graphing changes in population

Limiting Factors

Food space Weather

Limiting factor is an environmental factor that prevents a population from increasing.

Food Limiting factor when food become scarce. No matter how much shelter, water and other resources are found, population will not grow without right amount of food.

Space Space is often a limiting factor of population because there is not enough room to repopulate

Weather Weather conditions such as temperature and amount of rainfall can also limit population growth.

Watch this video t=4&secNum=1 Watch this video: summarize in one paragraph what its teaching: /ecosystems/ecosystems.htm Watch this video: summarize in one paragraph what it is teaching (make sure to describe the difference between secondary and primary succession) /ecosystems/changes-ecosystems.htm Click on Ecosystem Terms / Ecosystem Quiz write the vocabulary word and definition