9Biotic FactorsAre the living things or their materials that directly or indirectly affect an organism In its environment.Some biotic factors include:Parasitismdiseasepredation
10Biotic Factors Producers Organisms that make their own food. Ex- Plants & some bacteriaConsumers:Organisms that eat (consume) other organisms for energy (animals)
11Biotic FactorsDecomposers: Consumers that eat waste products for energy. Waste products are feces, urine, fallen leaves, dead animals. (Fungi, some bacteria)
12ScavengersOrganism that eats other dead organisms
13Abiotic FactorsAre those non-living physical and chemical factors which affect the ability of organisms to survive and reproduceIncludes things such as:sunlighttemperaturetype of soil or rockwater availability
14Feeding Relationships Autotrophs: Organisms that make their own food (plants and some bacteria)Heterotrophs: Organisms that eat other organisms (they cannot make their own food)
27Habitat & Niche Habitat is where something lives Niche is an organism’s total way of life (how it eats, competes with others)
28FYI- NicheIncludes all its interactions with the biotic and abiotic parts of the environmentEach type of organism occupies its own niche to avoid competition with other types of organismsTwo species can share the same habitat but not the same nicheExample: Ants and bacteria both live in the dirt (habitat) but have different niches. Ants eat dead insects and bacteria eat dead leaves, dead logs, and animal waste. So ants and bacteria don’t compete for resources.
29Survival Relationships Predator-prey: predators are consumers that hunt and eat other organisms called prey.
30Survival Relationships Symbiosis: relationship in which one species lives on, in, or near another species and affects its survival.3 Types:MutualismCommensalismsParasitism
31Mutualism type of symbiosis in which both species benefit. Ex. Clownfish living in the sea anemones. It provides protection for the fish, and attracts potential food for the anemones.
33Commensalismtype of symbiosis in which one species benefits and the other species is neither harmed nor benefitedExample: Spanish moss grows on the branches of trees. The moss gets a habitat and the tree gets nothing.
34Parasitism one species benefits and the other species is harmed. Parasite: organism that harms but does not usually kill another organismHost: organism that is harmed by a parasiteEx. Ticks feed on dogs, people, etc. The ticks get food (blood) and the hosts lose blood and can be infected with disease.
35Abiotic Factors- Non-living parts of the environment. Ecology- Study of interactions between organisms and their environment.Consumer-organisms eat others for energy “heterotrophs”Producer- Uses the sun to make food “autotroph”Scavenger-eats dead organismsDecomposer- break down dead organisms and cause decay1. Organism- individual with all characteristics of life.2. Populations- groups of organisms of the same species.Biotic Factors- All the living parts of the environmentThe 5 Levelsof EcologicalOrganization3. Community- group of populations living together.5. Biosphere- part of the earth that supports life4. Ecosystem- living & nonliving parts interact together.
40Energy PyramidEvery time an organism eats, it obtains energy from its food.So energy is transferred from the 1st trophic level to the 2nd trophic level to the 3rd trophic level and so on.Some of this energy is lost along the way during an organism’s metabolism and as heat.This energy can be measured in kilocalories (kcal).
41Energy PyramidPicture that shows how much energy is transferred among the different trophic levels in a food chain; energy is lost as you move up the pyramid.Food chain: lineup of organisms that shows who eats who.Shows how matter and energy move through an ecosystem.
42Food WebsA food web is a network of connected food chains. More realistic than a food chain because most organisms feed on more than one species for food.
51Cycles in NatureThere is only a limited amount of resources (water, oxygen, nitrogen, carbon) on the earth.In order to keep these resources available to organisms, they must be recycled after they are used.Cycle: a process that recycles a resource so that you end up with what you started with.
52Nitrogen Cycle1. Nitrogen fixation: Bacteria in the ground change nitrogen from the atmosphere (N2) to different nitrogen compounds5. Denitrification: Bacteria change the nitrogen compounds back to N2 and release it to the atmosphere2. These bacteria live in plants and transfer the nitrogen compounds to the plants4. Bacteria eat the dead animals and animal waste and take in the nitrogen compounds3. Animals eat the plants and take in the nitrogen compounds
54Water Cycle 2. Seepage: Water seeps into the ground and plants use it 3. Transpiration: Plants give off water to the atmosphere1. Precipitation: Rain and snow fall from the atmosphere to the earth2. Runoff: Extra water runs off the land to lower-lying bodies of water3. Evaporation of water from the bodies of water back into the atmosphere
56Carbon Cycle1. Carbon dioxide (CO2) and oxygen (O2) are found in the atmosphere2. Plants use CO2 to make their own food (photosynthesis)2. Animals and plants use the O2 to make energy (respiration)3. During photosynthesis, plants release O2 back into the atomosphere3. During respiration, animals and plants release CO2 back into the atomosphere
59Populations What is a population? What are some factors that can contribute to the size of a population?
60Organism Interactions Limit Population Size Organisms depend on each other for:So what happens when these factors change?ProtectionFoodReproductionShelter
61Organism Interactions Limit Population Size Predation:What could happen if a predator is introduced to a population and there are no organisms to eat it?Unchecked for many years, the snakes caused the extinction of nearly every native bird species on the Pacific island of Guam
62Organism Interactions Limit Population Size 2. Competition- What can happen if resources become limited?
63Organism Interactions Limit Population Size 3. Crowding & StressAs pop. Increase in size and start straining their resources, they may become stressed. What are some examples of stress symptoms?AggressionDecrease in parental careDecreased fertilityDecreased resistance to disease
64How do you determine population size? Growth rate—amount that a population’s size changes over timeBirth rate—number of births occurring during a period of time (ADD)-- Death rate (or mortality rate)—number of deaths in a period of time (SUBTRACTS)
65How do you determine population size? Birth rate – death rate = growth rate- Positive number means the pop. is growing- Negative number means the pop. is shrinking
66Human population size Other things that affect a population’s numbers: Life expectancy—how long on average an individual is expected to liveUS men: 72 yrs, US women: 79 yrsImmigration—individuals moving into a population (ADDS)Emigration—individuals moving out of a population (SUBTRACTS)
67What can affect population size? When you figure out the number of individuals living in a certain area, this is called the population density.There are two limiting factors (biotic and abiotic) that can affect the pop. densityLimiting factor—any biotic or abiotic factor that restrains the growth of a population
68What are limiting factors? Density-independent factors—factors that affect the population regardless of the population’s sizeEx: fires, climateDensity-dependent factors—factors whose effects on the population depend on the population’s sizeEx. food shortages, disease
69Density- dependent or Density- independent Density- dependent or Density- independent? Take the following quiz to find out!
70Predation Volcanic eruption Chemical pesticides Parasitism Forest fire Density-dependentVolcanic eruptionDensity-independentChemical pesticidesParasitismDensity-dependentForest fireDensity-independentMigration
72FYI: How are communities formed? Communities are made of several populations living togetherThink back to population size. What are some limiting factors that can affect a community?
73FYI: Forming Communities What would happen if people stopped cutting the grass in their yards?1. The grass would get taller & weeds would grow2. Later, bushes would grow; trees would appear, and different animals would enter the area3. After 30 years, it would eventually become a forest…BUT WHY?
74Forming CommunitiesSuccession—orderly, natural changes and species replacements that take place in the communities of an ecosystem
75CommunititesPrimary succession—development of a community in an area that did not previously existEx: new volcanic island, bare rock, sand duneHappens slowly