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Biology - Unit 5
Community Interactions & Hierarchy
Ecology: The study of organisms and their interactions with their environment/surroundings.
Economics: consumption of resources
How are they related to each other?
Economics and ecology are related since the economy consumes the environment through the consumption of resources like wood, clay, stone, etc.
What are the levels of organization in an ecological system?
Level of Organization in the Biosphere -
Community - different populations living together in the same area
Biome - a group of with similar climates and typical organisms
Species - similar organism that can breed (individual organism)
Biosphere - the global ecological system integrating all living beings and their relationships
Ecosystem - all the organisms in a certain place together with their physical environment
Population - group of individuals of the same species living in the same area
What does the biosphere include?
All living beings and their relationships (hydrosphere, lithosphere, geosphere, and atmosphere)
Levels of organization ordered from largest to smallest:
Biosphere
Biomes
Ecosystems
Community
Population
Species
Explains the difference between a species and population.
Species are the similar organism that can breed together and population is the groups of the organism in a certain area.
Explain the difference between a population and a community.
A population is the group of individuals of the same species living in the same area and a community is the different populations living together in the same area.
Provide an example of an organism, population, community, and ecosystem found in Edison.
Organism: Robin
Population: population of Robins
Community: squirrels, chipmunks, robins, and foxes
Ecosystem: wetlands, watersheds, and areas with diverse wildlife
Biome: temperate forest deciduous
Any living part of the environment with which an organism might interact is known as a biotic factor, while the physical (nonliving) parts of ecosystems are called abiotic factors.
Which of the 6 levels of organization include abiotic factors?
Species, Population, Community, Ecosystems, Biomes, and the Biosphere.
What makes up an ecosystem?
Biotic factor: living
Abiotic factor: nonliving
Pick an organism and name 4 biotic factors related to it:
Organism: Frog
Lily Pad - jumps on it
Grass - uses it to hide
Trees - structure
Forest - use it to hide
Using the same organism, name 4 abiotic factors related to it:
Air - uses it to breath
Rocks - stands on it
Water - hydration and reproduction
Soil - stands on it
Is a mucky shoreline around a pond strictly part of the physical (abiotic) environment? Explain.
A murky shoreline would not be considered to be abiotic due to the fact that living things can live in or on it.
Ecosystem Review
All biotic and abiotic factors of an ecosystem are interrelated. In nature, if one factor is changed or removed, it affects the availability of other resources within the ecosystem.
All of the rocks (Abiotic) are removed from a desert ecosystem. What would happen to the population of rock dwelling lizards (Biotic), and the animals which eat them?
The population of the rock dwelling lizards would decrease and would not have anywhere to hide allowing them to become prey easily for predators. The population of the predator population would increase since they are able to find prey that aren’t camouflaged.
A ten-square mile area of trees (Biotic) is removed from the tropical rainforest. How will this affect the amount of water (Abiotic) and the amount of oxygen (Abiotic) in the area?
The amount of the water and oxygen would decrease when trees are removed from the rainforest due to the fact of less primary production from the photosynthesis of the trees and also the lack of trees there is the less oxygen there will be for the trees to use for photosynthesis.
Why is soil considered both a biotic and abiotic factor?
Soil is considered to be abiotic because soil itself is not living but can be considered to be biotic when hosting a living organism.
Where do Organisms Get Their Energy From and Where Does it Go?
Energy, Producers, and Consumers
Organisms must get energy in order to function
Different organisms get their energy in different ways
Almost all energy on Earth originates from the sun!
Autotrophs
Organisms that capture energy from sunlight or chemical compounds and turn it into food are known as autotrophs.
Also called Producers and Consumers.
Most autotrophs use energy from the sun to create sugars and starches. This process is known as photosynthesis.
Three examples of this is: Plants, Algae, and certain bacteria (cyanobacteria)
Chemosynthesis
When primary producers convert the chemical potential energy in bonds (like hydrogen sulfide) into carbohydrates.
Mostly done in deep-sea hydrothermal vents
Found in extreme environments (deep ocean, hot springs, volcanoes)
Why is it so important to all living things that there is a source of energy in their ecosystem?
All living things need to reproduce, grow, and survive without energy; these vital things will not be possible.
Heterotrophs
Heterotrophs eat other organisms for food. Heterotrophs are also called consumers.
Consumers are organisms that cannot directly harness energy from the environment as autotrophs do. They are classified by specific ways in which they acquire energy and nutrients from other organisms. The type of “food” eaten may vary widely from one type of consumer to another.
Types of Consumers -
Herbivore: organisms that obtain energy by eating plant leaves, roots, seeds, and or fruits (ex: cow, grasshopper, and deer)
Carnivore: organisms that obtain energy by eating animals (ex: fox, sharks, and lion)
Omnivore: organism that obtains energy by eating both plants and animals (ex: pigs, hedgehogs, and humans)
Decomposer: organisms that break down and obtain energy from dead organic matter (ex: bacteria, fungi, like mushshrooms)
Detrivore: organisms that feed on detritus which are small pieces of dead and decaying plant and animal remains (ex: dung beetles, earthworms, and shrimp)
Scavenger: animals that consume the carcasses of other animals (ex: hyenas, and vultures)
What Happens When There is a Disturbance in a Food Web?
Food Chains and Food Webs
Energy flows through an ecosystem in a one way direction from producers to consumers.
Food Chain - a series of steps in which organisms transfer energy by eating and being eaten.
Food web - a network of food chains formed by the feeding relationships among the organisms of an ecosystem.
Are food webs or food chains a better representation of feeding relationships in ecosystems? Why?
Food webs are the better representation of feeding relationships in an ecosystem because they include all of the interactions.
What do you think would happen to the ecosystem above if the vulture was killed off?
The vulture being killed off would lead to a prey since the population of lion is going to increase since it would not become prey to the vulture.
Scavengers, Detritivores, and Decomposers -
Most primary producers (algae/plants) die without being eaten.
Scavengers are organisms that consume dead/decaying animals.
What are the health benefits for other organisms in the ecosystem when a scavenger eats decaying flesh?
Scavengers get rid of carcasses of dead animals which recycle them.
Decomposers (bacteria and fungi) are organisms that break down this dead plant material into detritus. (this recycles material back into the soil to provide energy for growing primary producers)
Detritus is eaten by detritivores (like shrimp and worms), further releasing nutrients into the soil.
Summarize the importance of decomposers and detritivores in food webs.
Decomposers obtain energy through breaking down dead organic matter without this process of decomposition. All of this dead organic matter would have nowhere to go.
Detritivores obtain energy through feeding on detritus which are pieces of dead/decaying plant and animal remains; this is important because without this decomposition would not be able to occur.
How is Energy Transferred in an Ecosystem?
There are 2 major types of biological macromolecules that provide energy for organisms: carbohydrates (provides energy) and lipids (stores energy).
Food chains show the path of energy through an ecosystem. As you move through a food chain, energy is lost. Scientists estimate only 10 percent of energy passes from one level to the next. This is why most food chains are not very long.
Imagine this food chain: A hawk eats a robin. The robin ate a grasshopper. The grasshopper ate grass. Which organism is the source of energy for this food chain?
Grass is a primary producer making it the source of energy in this food chain.
In a food chain, do carnivores or the herbivores receive more of the energy supplied by the producers at the base of the food chain? Explain.
The herbivores receive more energy from the producers than carnivores do since herbivores receive 10% while carnivores receive 1% of the energy.
Only 10% of the energy in one trophic level is passed to the next level up. The rest of the energy is either used by organisms to do life processes or (like growth, reproduction, respiration, etc.), or released as heat.
Trophic Level: Each step in a food web.
Which trophic level always includes primary producers?
First Trophic Level
Which type of organisms occupy all the other trophic levels?
Decomposers
Ecological Pyramids show the relative amounts of energy of biomass (in terms of living matter or numbers of individuals) contained in each trophic level in a given food chain or food web.
What are the three types of ecological pyramids?
Pyramid of energy, pyramid of numbers, and pyramid of biomass.
A Pyramid of Energy shows: The relative amount of energy available at each trophic level of a food chain or food web.
Less energy as the levels increase
Energy is lost due to:
Some energy is used for daily activity (cell work, homeostasis, etc.)
Some energy is used for release (lost) heat to the environment
Some energy is never consumed. Undigested waste is used by decomposers.
The diagram shows that a large amount of energy is released from each step as “heat”. Which essential metabolic process creates this heat?
Cellular Respiration
Gross vs. Net Productivity
Gross Primary Productivity: all the energy (glucose) the plant ever produced from sunlight
Net Primary Productivity: gross primary productivity minus all energy used in cellular respiration and eventually heat. This is what is available to the next trophic level. Also known as biomass (all organic compounds minus water)
A Pyramid of Biomass shows: The relative amount of living organic matter available at each trophic level in an ecosystem.
Biomass: The total amount of living tissue at a given trophic level. It is usually measured in grams of organic matter per unit area.
The amount of biomass a given trophic level can support is determined, in part, by the amount of energy available.
A Pyramid of Numbers shows: The relative number of individual organisms at each trophic level in an ecosystem
In most ecosystems, the shape of the pyramid of numbers is similar to the shape of the pyramid of biomass for the same ecosystem. In this shape, the numbers of individuals on each level decrease from the level below it.
Describe an example in which a pyramid of numbers may be turned upside whereas the corresponding pyramid of biomass would have the normal orientation.
In a forest ecosystem, a few large trees support many insects, creating an inverted pyramid of numbers. However, the pyramid of biomass stays upright, as the trees’ total weight is greater than that of the insects and the other animals they support.
Follow up: Life or Death Food Chain Decision
A group of people are stranded on a barren desert island. They have 500 bushels of wheat and one cow. What should they do to survive for the longest amount of time?
Eat the cow and then eat the wheat
Drink the cow’s milk, eat the cow, and then eat the wheat
Feed the wheat to the cow and then drink the milk
Feed the wheat to the cow, drink the milk, and then eat the cow
Eat the wheat and then eat the cow
First, think about this question by yourself. Which answers do you think are the best ones?
First, second, and fifth option would be the best.
Which of those makes the most sense? Why?
This option “Drink the cow’s milk, eat the cow, and then eat the wheat” makes the most sense. The cow already produced the milk and used energy to do that. Therefore, you would want to consume that milk. Then, you would want
to kill and eat the cow because the longer it lives, the more energy is lost to
its metabolic process. Finally, eat the wheat yourself so that you are getting the most energy you possibly can from it (in comparison to letting the cow eat . . . That would put one more trophic level between you and the wheat).
Next, discuss this question with your lab group. Rank the responses from best to worst in terms of energy efficiency. Be able to explain and justify your group’s choices.
Drink the cow’s milk, eat the cow, and then eat the wheat
Eat the cow and then eat the wheat
Eat the wheat and then eat the cow
Feed the wheat to the cow, drink the milk, and then eat the cow
Feed the wheat to the cow and then drink the milk
6) How do Organisms Interact with their Environment and Each Other?
Niche: describes not only what an organism does, but also how it interacts with biotic and abiotic factors in the environment.
A niche is the range of physical and biological conditions in which a species lives and the ay the species obtains what it needs to survive and reproduce.
Physical Aspects of the Niche:
an organism’s niche involves the abiotic factors it requires for survival such as sunlight, water, temperature, space, and minerals.
Biological Aspects of the Niche:
an organism’s niche involves certain biotic factors required for survival such as reproduction, obtaining food and nutrients.
Habitat: area where an organism lives including the biotic and abiotic factors that affect it
The general place where an organism lives -its address! (Living space)
Tolerance: is the ability to survive and reproduce under a range of environmental circumstances. Each organism has an optimum range for best survival and reproduction.
Examples of environmental circumstances: Temperature, pH, and rainfall
A species’ tolerance for environmental conditions helps determine its habitat.
Outside of optimum ranges, the organism experiences stress because it has to expand more energy to maintain homeostasis, leaving less available energy for growth and reproduction. Every organism has an upper and lower limit of tolerance for every environmental factor. Beyond those limits, the organism cannot survive.
Ex:
“The red fox’s habitat might include forest edges, meadows and the bank of a river. The niche of the red fox is that of a predator which feeds on the small mammals, amphibians, insects, and fruit found in this habitat. Red foxes are active at night. They provide blood for blackflies and mosquitoes, and are the host to numerous diseases. The scraps left behind after a fox’s meal provide food for many small scavengers and decomposers.”|
Choose an organism of interest to you (any organism): Birds
Write a short description of the niche for the organism based on your background knowledge (habitat and role).
Birds create nests in trees to host their children. They feed their children through worms from the dirt.
What is the result if two species do attempt to occupy the same niche?
If two species attempt this, they compete for the same resources which over time one species will outcompete the other leading to competitive exclusion.
Instead of competing for similar resources, species usually divide them.
Ex: Three different species of a kind of bird called a warbler are coexisting in this tree, even though they eat the same kind of food. These birds are feeding in different levels of this tree. In this way, these birds evolved to occupy different niches.
By causing species to divide resources, Niche partitioning helps determine the number and kinds of species in a community and the niche each species occupies.
Predator-Prey Relationships
Predation: an interaction in which one animal (the predator) captures and feeds on another animal (the prey) places prey can live and feed.
Ex: Wolf and Deer
Competition
When organisms attempt to use the same resources, competition occurs.
Ex: the roots of different plants compete for water, nutrients, and space in the soil
Types of Competition
Intraspecific - competition between the members of the same species
Interspecific - competition between the members of different species
The Competitive Exclusion Principle
The idea that no two species can occupy the same niche, in the same habitat, at the same time.
If two species try to do this, one species will compete better for the niche and the other will either leave or die out.
Herbivore-Plant Relationships
Herbivory: an interaction in which one animal (the herbivore) feeds on producers (such as plants)
Herbivores can affect both the size and distribution of plant populations in a competitive area and determine the places that certain plants can survive and grow.
Ex: Caterpillar and leaves, squirrels and acorns, fruits, cows and grass.
The predator population increases causing the prey population to decrease.
The predator population would dramatically decline since there is fewer prey for them.
Symbiotic Relationships
Define Symbiosis: Relationship between two or more organisms that are closely together
Commensalism: One organism benefits and each other is neither harmed/helped.
Ex: Barnacles attached to whales and birds building nests in trees.
Mutualism: Both organisms benefit from interaction
Ex: Bees pollinating flowers and Clownfish living in sea anemones.
Parasitism: One organism benefits and other is harmed
Ex: Tapeworms and Fleas, mosquitos/humans (malaria)
Why are microbes important for human health?
Microbes are important because the help with digestion, produce vitamins, and boost immune health through oligosaccharides.