Semester 2 Final Review Part 2 Carbohydrates, Photosynthesis & Respiration and Ecology

DECOMPOSERS Cause decay and release essential nutrients back into the environment to be recycled. 1. Scavengers 2. Detritivores 3. Saprotrophs

Obtain their energy from organic wastes and dead bodies that are produced at all trophic levels Ex vultures. 1. Scavenger:

Scavergers can also include: Secondary (2nd Order) CONSUMERS (Omnivores)- Omnivore Eats herbivores as well as being a scavenger Ex. Bear, racoon

2. Detritivore : Consume detritus (dead organic matter) Ex. Worms

3. Saprotrophs Feed exclusively on dead or decaying organic material. Saprophyte: Release digestive enzymes to break down organic material in their surrounding environment and survive by taking up the simpler soluble substances produced (spit and suck) Ex. Fungi, bacteria

FOOD WEB

shows the interactions between a wide variety of organisms in the environment creating a complicated, interconnected path of energy flow. are used to study effects of the changing or introduction of a variable in an environment

Ecological Pyramids: graphs which illustrate the trophic levels in a community.

Does all the energy this caterpillar eats get passed to the bird who eats him? Plant material eaten by caterpillar 100 kilocalories (kcal) Feces 50 kcal Growth 15 kcal Cellular respiration 35 kcal

Most ecological pyramids are large at the base and narrow at the top. This is because every time that an organism is eaten by the next trophic level, some of the energy is lost as heat. More Energy Less Energy

Pyramid of Biomass: Illustrates the amount of biomass in each trophic level –Biomass weight is determined after dehydration Shows the amount of matter lost between trophic levels. Measured in Kg, grams or pounds

Pyramid of Energy: Shows the energy available at each trophic level. –The size of the blocks represents the proportion of productivity –Measured in Joules or Calories

Pyramid of Numbers: Illustration of the number of organisms at each level

POPULATIONSDefinition: All the members of a species that live in one place at one time.

PROPERTIES of Populations Population SIZE  The number of individuals in a population Population DENSITY  Number of individuals per unit of area DISPERSION  SPATIAL distribution of individuals within the population Uniform Random Clumped

RATE Population Growth RATE Definition The amount by which a population’s size changes over time.

RATE Population Growth RATE Depends on:  Birth  Death  Emigration: movement of individuals OUT OF a population  Immigration: movement of individuals INTO a population

EXPONENTIAL Model of Population Growth Population increases rapidly with no limit What will a graph look like? Rare in nature. Why? “J” shaped curve Limit on the amount of resources (food / space)

Population Growth Limited by Carrying Capacity Definition: The number of individuals the environment can support over a long period of time

LOGISTIC Model of Population Growth Accounts for influence of limiting factors (like food, space) What will the graph look like? Stretched out “S” When population is small, birth rate is higher than death rate As population reaches carrying capacity, death rate increases When at carrying capacity, birth rate is equal to death rate

Population Size REGULATION regardless 1. Density Independent Factors : reduce population regardless of population size Examples:  Weather  Fires  Floods

Population Size REGULATION 2. Density Dependent Factors : triggered by increasing population density Examples  Food shortages  Space limitations  Waste accumulation

Example of Exponential Growth Phase (J- Shaped Curve) Ex. Human Population  Human population increased relatively slowly until about  It then doubled in the next two centuries  It doubled again in the next 80 years.  Our population is now about 6.9 billion. This increases by 80 million/year This in an increase of 214,000/day. It takes 3 years for the world population to add the population equivalent of another US.

Ecological Principles Vocabulary Biome PredationDecomposer ParasitismScavenger Biodiversity MutualismDetritivore CommensalismSaprotroph PopulationPyramid of Energy Food ChainPyramid of Biomass Food WebPyramid of Numbers AutotrophPopulation ProducerImmigration Trophic Levle HeterotrophEmigration Ecology Consumer Logistic Biosphere -primary, etc…Exponential Habitat HerbivoreCarrying Capacity Biotic/Abiotic Omnivore Density Dependent Limiting Factor Community Carnivore Density Independent Limiting Factor Dispersion Patterns