Ecology: The study of Interactions among Organisms and its environment including: Abiotic factors are nonliving factors such as temp. soil, air, rocks Biotic Factors are living parts of the ecosystem

Populations vs. Communities: A population is a group of organisms of the same species living in a certain area All populations interacting together in a given area is a community Ex. Frogs + fish + algae = community

Habitats are: Place in the ecosystem where an organism lives Determined by both biotic and abiotic factors Ex. Earthworm = moist soil, dead organic material

Niche: The role of the organism in its environment Includes feeding habits, reproduction, habitat, and what it contributes to its surrounding

Ecosystem is a community and its physical environment including biotic and abiotic factors

Autotrophic and Heterotrophic Nutrition :

Autotrophs: Make their own food  PRODUCERS Provide food to consumers Most carry out photosynthesis (solar light energy being converted into food  glucose!!) Ex. Green Plants!! Some producers are chemosynthetic – ability to create food by using energy stored in inorganic molecules

Autotrophs:

Heterotrophs: Are also known as consumers Cannot make their own food Must obtain their food from their environment

Heterotrophs:

Types of Heterotrophs include: Herbivores eat only plants

Types of Heterotrophs include: carnivores eat only meat predators- kill and eat their prey prey - the animal that is killed and eaten scavengers feed on dead and decaying meat ex. Buzzards, crows, hyenas

Types of Heterotrophs include: omnivores – eat both plant and animals ex. US!!, bears and…???

Types of Heterotrophs include: Decomposers (aka. saprobes) get nutrients from breaking down dead plants & animals Ex. bacteria, fungus, mushrooms

Symbiosis (Symbiotic Relationships): 2 organisms living together where at least 1 organism benefits

3 types of symbiotic relationships: 1. Mutualism 2. Commensalism 3. Parasitism

Mutualism mutualism - both organisms benefit from the association Ex. Humans and bacteria in the digestive track Ex. Fish in sea anemones Ex. Flower and the bee

Commensalism Commensalism - one organism benefits the other is not effected (not harmed, no benefit) ex. Remora fish and sharks ex. Orchids/moss living in tree

Parasitism: Parasitism - one organism benefits at the cost of the other (host) ex. parasites living in animals (tapeworm, tick) often cause disease

Energy Flow in an Ecosystem: Includes: producers (Autotrophs ) make their own food consumers (heterotrophs) obtain or eat their food from the environment Decomposers (a.k.a saprobes ) break down left over remains of plants and animals

FOOD CHAINS: Are a transfer or 1 pathway of energy through an ecosystem Solar Energy from the sun is converted by producers (photosynthesis) into chemical energy or FOOD

FOOD CHAINS cont… Show the relationship b/w Producers and Consumers Energy is transferred from the producer to the consumer that eats it. Herbivores are first order consumers gaining the most energy from the producers Omnivores and Carnivores are secondary consumers getting left over energy

FOOD CHAINS cont… The feeding relationship shows the transfer of energy which forms a food chain The transfer of energy moves from producer to consumer to decomposers Ex. Sun  plant  grasshopper  bird  cat Decomposers

Producers consumers consumers consumers (plants) (1st level) (2nd level) (3rd level) Examples of food chains: Grass  grasshoppers  robins  hawk

FOOD WEB food chains (1 pathway of energy) which are interconnected = food webs Food webs are many food chains interacting together Each arrow in the food web means consumed (EATEN) by…

FOOD WEB

Energy Pyramids ARE: Another way of showing the flow of energy in an ecosystem

Energy Pyramids Each step in a feeding relationship is called a trophic level 1st trophic level = producers 2nd trophic level = primary consumers 3rd trophic level = secondary consumers

The greatest amount of energy is at the bottom of the pyramid (producers), the least amount of energy is at the top.

90% of Energy is lost moving at each level, only 10% is transferred to the next level Some of the Energy is used in cell activities (growth, cell division), the rest is lost as heat

The Carbon Cycle: An exchange of materials (carbon dioxide, oxygen) between autotrophs and heterotrophs

The Carbon Cycle:

Cycles in Nature: Autotrophs: use the sun’s energy to produce their own food in a process called photosynthesis In photosynthesis CO 2 is absorbed (taken in) from the environment and O 2 (Oxygen) is released as a waste.

Cycles in Nature: Heterotrophs: take in the Oxygen and use it for cellular activities Releases CO 2 into the environment as a waste The process is called cellular respiration

The Carbon Cycle: The Carbon Cycle is a balance between Carbon Dioxide and Oxygen in the air.

Remember… A population is a group of organisms of the same species living in a certain area

Discussion on Populations: change over time Most stabilize rather than continuously grow As populations increase in #, it puts more demand on the resources available such as food, shelter, and water Environmental factors that limit the size of a population are called limiting factors.

Limiting Factors: Environmental factors that limit the size of a population The availability of resources Ex. Food, water, shelter, oxygen, sun

Density-Dependent Factors: limit the growth of a population when the population reaches a certain size Ex. Disease, competition, predators, and food Population Density The number of organisms in a given area Predation, competition, and the spread of disease all are influenced by population density

Question: what happens to the level of competition when the population density increases? Predation? Disease?

Population Cont. predator- prey population cycles

Density Independent Limiting Factors: limit growth in a population regardless of size These factors are often climatic events Ex. Extreme temp, drought, volcanoes flooding

Carrying Capacity: The largest number of organisms (of one species) that can be supported for an unlimited amount of time Occurs when # of deaths and births are about equal If a population goes over the carrying capacity the number of deaths is greater than the # of births If the population is under the carrying capacity then…

Carrying Capacity

Population Growth Rate Involves:  Birth and Death rate influences the population growth Life expectancy of humans Man-72 years Woman-79 years

Population Growth Rate Involve: Immigration-movement of individuals into a population Emigration -movement of individuals out of a population

Graphs & Populations Exponential Model: Describes a population that increases rapidly after only a few generations The larger the population gets, the faster it grows “J” shaped curve

Logistic Model: Takes Limiting factors into account Includes carrying capacity -the number of individuals the environment can support over a period of time Increased birth rates causes growth rates to increase Growth will decrease when a population reaches the carrying capacity. Birth rate = Death rate when a population reaches carrying capacity therefore GROWTH

Logistic Population Growth

After discussing topics in ecology such as: the flow of energy, balance among organisms and populations, what type of impact do you feel humans have on the environment? Why?