Day 44 Population Growth
Structure of living things
Life is organized by levels
-Atom
-Molecule- Two or more atoms bonded together
-Cell- The smallest unit of life
-Tissue- A group of similar cells
-Organ- A group of similar cells working together
-Organ System- A group of organs working together
-Multicellular Organism- A complete living thing
-Species- Organisms that can reproduce and produce a fertile, viable, offspring
-Population- A group of the same species
-Community- All the species in an area
-Ecosystem- All the biotic (living) and abiotic (non-living) things in an area
-Biosphere- The earth
Ecology is the relationship of organisms to their environment and other organisms
Habitat- A habitat is all the biotic and abiotic characteristics in an area where an animal lives
Each organism has its own Niche
-A niche is what you eat, the land you take up, and how you live
-If another organism has the same niche then they are competition for each other
-Most organisms in the same ecosystem develop a slightly different niche to avoid competition
-Interspecific competition- When different species compete
-Intraspecific competition- When members of the same species are competing
Growth Rate
Growth rate = Birth rate - Death rate
r = b - d
Things that affect biotic potential
-The age at which the organism first reproduces
-The frequency at which reproduction occurs
-The average number of offspring produced each time the organism reproduces
-The length of the organism's reproductive life span
-The death rate of the individuals under ideal conditions
Boom and bust populations - have as many offspring as possible and then die out every season
-Flies and most insects
Logistic growth - Grow to the maximum level the environment can handle and then stabilize
Carrying capacity
-Each ecosystem has a carrying capacity for each of its organisms
-The carrying capacity is how large of a population that ecosystem can support
-K stands for carrying capacity
-A J-Curve represents exponential growth
-An S-Curve is when exponential growth evens out with its carrying capacity
-An S-Curve represents logistic growth
Predators and Prey affect each others carrying capacity
Human Population Growth
Environmental Resistance
-Density-independent - factors that limit population size regardless of the population density
-Density-dependent - Population is controlled once it reaches its carrying capacity
Interactions with each other
-Predators
-Prey
-Carnivores
-Herbivores
-Detritivores
-Detritus waste is left over biotic parts
-Decomposers
-Producers
Symbiosis
-Symbiont-smaller one
-Host-Larger one
-Commensal- One benefits and the other is not affected
-Parasitism- One benefits and the other is hurt
-Mutualism- Both benefit from each other
Trophic Levels
-First level
-Primary Producer
-Second level
-Primary consumers
-Third level
-Secondary consumers
-Fourth level
Tertiary consumers
-It ends with what we call Top Predators
This structure is represented with a food web
Biomagnification is a result of trophic levels
-Each trophic level up becomes magnified by 10
-So each level has more toxic chemicals than the last by 10 times
The higher up on the trophic level the organism is the higher the concentration of toxic chemicals
This works the opposite way when we talk about calories
-Each level we go up on the trophic level we lose 10 times the calories
