Unit 8: Populations and Communities

I. Organisms and the Environment a.An organism gets food, water, shelter from their environment as well as other needed materials to help them live, grow and reproduce b.A habitat is the place that provides the specific needs for the organism

I. Organisms and the Environment c. Two parts to a habitat i. Biotic Factors: these are the living parts or once living parts of the habitat 1. These are the plants, animals, predator, prey, decomposing matter and scat that is found in the habitat ii. Abiotic Factors: these are the non-living parts of the habitat 1. Such as the sunlight, rainfall, temperature, soil, oxygen and water

II. Energy Flow in Ecosystems a.Every organism in an ecosystem fills the role of a producer, consumer or decomposer b.Producer: these organisms use the sun’s energy and can produce their own food i. Most use photosynthesis to create their food ii. They are the source of food for the whole ecosystem

II. Energy Flow in Ecosystems c. Consumer: these organisms cannot make their own food i. Therefore, they must feed off other organisms ii. Three Types of Consumers 1. Herbivore: eats only plants Example: ________________ 2. Carnivore: eats only animals Example:_________________ 3. Omnivore: eats both plants and animals Example: _________________

II. Energy Flow in Ecosystems d. Decomposer: break down wastes and dead organisms and return the raw materials to the ecosystem i. Without these organisms, waste would pile up, dead organisms would pile up, and the raw materials needed for life would run out (such as Carbon and Nitrogen) ii. Example:_____________________

II. Energy Flow in Ecosystems e. Movement of Energy i. Energy moves through an ecosystem when one organism eats another ii. Food Chain: (diagram) iii. Food Web: (diagram)

II. Energy Flow in Ecosystems f. Energy Pyramid i. this shows the amount of energy that moves from one feeding level to the next ii. As you move up an energy pyramid the energy level reduces iii. In general, only 10% of the energy from one level gets passed to the level above it iv. 90% of the energy on each level is turned into heat v. Due to the reduced energy level at the top of the pyramid there are normally less consumers supported by an ecosystem

How much energy is passed up the pyramid if it starts with 1000 kcals

III. Interactions among living things a.Vocabulary i. Species: a group of organisms that can mate with each other and produce fertile offspring ii. Population: all members of one species living in a particular area iii. Community: all the different populations that live together in an area iv. Ecosystem: the community of organisms that live in a particular area, along with their Abiotic factors. v. An organism is part of a species, which is part of a population, which is part of a community, which is part of an ecosystem

III. Interactions among living things b. Two major interactions between organisms i. Competition: the struggle between two different organisms trying to survive off the same resources 1. Every ecosystem has a limited amount of food, water, and shelter to offer to the organisms living there

III. Interactions among living things ii. Predation: when one organism kills another organism for food or nutrition 1. Predator: the organism that does the killing 2. Prey: the organism being killed 3. Giraffes and Cows are also considered predators because they eat plants

Warm Up 1 Re-write the question, you do not need to write in complete sentences 1.What are the two different factors of a Habitat? 2.Give some examples of both of the above factors. 3.Describe a Produce, Consumer, and Decomposer. 4.Give an example of two things the Robin Eats. 5.Give two animals that are eaten by the Alligator Lizard. 6.What eats Pill Bugs?

III. Interactions among living things c. Predator/Prey relations i. This is a very delicate balance ii. If the death rate exceeds the birth rate of a population than the prey population will decline iii. However, if the prey population declines there is now less food for the predator so then the predator population will decline iv. Populations of predators and their prey will rise and fall in cycles

v. What will happen as the predator population decreases? __________________________________

III. Interactions among living things d. Symbiosis i. This is another type of interaction that can occur between organisms ii. This is a relationship between two organisms, in which they live closely together and at least one organism benefits iii. Three types of symbiosis: mutualism, commensalism and parasitism

III. Interactions among living things iv. Mutualism: a relationship in which both organisms benefit 1. Example: In South America, a species of acacia trees and stinging ants live closely with one another. The acacia trees offers protection to the ants because of thorns and the ants attack other animals that approach at the tree and clear competing plants away

III. Interactions among living things v. Commensalism: a relationship in which one organism benefits and the other organism is neither helped nor harmed 1. Example: A bird building a nest in a tree. The bird is protected by the tree but the tree is not harmed nor helped

III. Interactions among living things vi. Parasitism: a relationship in which one organism live on or in another organism and harms it 1. Parasite: the organism that lives in or on another organism and benefits 2. Host: the organism that the parasite live in or on and is harmed by the relationship 3. Example: Tape worms live in human intestines, they grow by eating all the humans food, humans are harmed because they do not receive nutrients

IV. Populations a.Populations can change in size when new members join the population or leave the population b.Birth vs. death rate i. Birth Rate: number of births in a specific population in a certain time period ii. Death Rate: number of deaths in a specific population in a certain time period

IV. Populations iii. Chart and graph to see population changes 1. We have observed a baby alligator population here in Sarasota over 4 years and this is what we found YearBirthsDeaths

IV. Populations c. Immigration vs. Emigration i. Immigration means moving into a population ii. Emigration mean moving out of a population 1. Emigration may happen if the food or water supply is scarce. Therefore, some of the population may move to find food and water and never return to their original population

IV. Populations iii. Graphing change in populations YearNumber of Rabbits

IV. Populations d. Population Density i. Number of individuals in an area of a specific size ii. Population Density Equation

IV. Populations Example: if you have 45 rabbits in a wooded area that is 15 square meters, what is the population density?

IV. Populations What if there were 60 rabbits in the same amount of space?

IV. Populations Why does population density matter? __________________________________ __________________________________ __________________________________ __________________________________ ____________________

IV. Populations e. Limiting Factors i. a limiting factor is an environmental factor that causes a population to stop growing or decreasing ii. Examples: food, shelter, water, space, disease, parasitism, predation, nesting sites

IV. Populations iii. Food Limiting Factor 1. Carrying Capacity: the largest population that an area can support 2. Example: If a giraffe needs to eat 10 kilograms of leaves daily and there is a tree that can provide 100 kilograms of leaves a day while remaining healthy than 5 giraffes can easily live off this tree However, 15 giraffes living in this area would kill the tree

IV. Populations iv. Shelter Limiting Factor 1. If an organism cannot find shelter, they could be run out of an area, hunted, preyed upon. 2. They also do not have a place to birth, raise, and grow their young

IV. Populations v. Water Limiting Factor 1. It is not only the water quantity that matters but also the water quality 2. Without clean drinking water all organism will die off 3. Without a lot of water, there may not be enough for all organisms plus the organisms that live in the water, will no longer be able to survive

IV. Populations vi. Space Limiting Factor 1. Plants in particular need a lot of space to put out roots, get water, have enough soil for support vii. Disease Limiting Factor 1. In densely populated areas disease spreads much more rapidly 2. During warm or rainy periods, crops can develop a disease called blight which causes all leaves to rot and fall off 3. Disease can pass from plant to plant or from prey to predator

IV. Populations viii. Predation and Parasite Limiting Factors 1. If the predator or parasite population is very large in a given area this will limit the number of animals that will survive in that area

IV. Populations ix. Nesting Site Limiting Factor 1. There are only certain areas where organisms nest and raise the next generation 2. If those run out, a pair will not be able to raise the next generation and be added to the population