ecology: the study of interactions among organisms and its environment including: abiotic factors...
TRANSCRIPT
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. Mutualism2. Commensalism3. 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 CO2 is absorbed (taken in) from the environment and O2 (Oxygen) is released as a waste.
Cycles in Nature:
Heterotrophs: take in the Oxygen and use it for cellular activities
Releases CO2 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 resourcesEx. 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?