Topic 4: Ecology

Define consumer

heterotrophs that ingest other organisms to obtain their organic molecules

Explain how rising co2 levels are a threat to coral reefs

increased co2 concentrations in the air lead to increased dissolved co2 in the oceans, which lowers pH of seawater. ocean acidification leads to death of coral polyps and algae, and when they die the reefs aren't built up anymore. the rich color of coral goes bland. leads to "bleaching" and interrupts food chain.

Saprotroph

live on or in non-living organic matter

Autotroph

- able to synthesize their organic molecules from simple inorganic substances to make their own food. - get their energy from the sun - ex.) grass, trees, algae

Heterotrophs

- cannot make their own food, must obtain organic molecules from other organisms - get their energy from autotrophs or other heterotrophs - ex.) fish, sheep, insects

Global warming is a natural phenomenon

- humans being the cause is a theory - there is research showing that climate change is NOT due to human activity - burning fossil fuels are increasing so why isn't the temperature increasing equally as fast? - huge fluctuations are natural

What factors allow an ecosystem to remain sustainable?

- nutrient cycling - continuous energy availability (light from the sun) - recycling of waste (certain by products of metabolism)

Global warming is caused by rising co2 emissions

- temperature has increased since industrial revolution - human activities produce particles in the air that remain in suspension - 100 year storms are supposed to occur every century but now they are occurring several times in a decade - letting people introduce more and more greenhouse gases will increase highly destructive patterns

Explain where the energy goes as it passes up on a food chain

- toxic waste organic molecules are excreted - some ingested material isn't absorbed and ends up being digested - some parts of an organism remain uneaten (wooley fibres from plants and the bones of animals)

Explain how to conduct chi-squared test

1. define hypothesis 2. complete contingency table of observed data 3. calculate expected values (row total x column total / grand total) 4. calculate the chi-squared value 5. determine the degrees of freedom (rows - 1)(columns - 1) 6. compare the x^2 value with the critical values and validate the hypothesis

what is the role of the snake in this food web?

A - heterotroph

which of the following ecological units includes abiotic factors?

B - an ecosystem

the scarlet cup fungus obtains its nutrition from decaying wood by releasing digestive enzymes into the wood & absorbing the digested products; which of the following terms describe the fungus: autotroph, heterotroph, saprotroph?

B - heterotroph and saprotroph

what is a community composed of?

B - populations

why do food chains in an ecosystem rarely contain more than five organisms?

C

slime moulds are protoctists that feed on organic matter, bacteria, and protozoa. which terms describe their nutrition: detritivore, autotroph, or heterotroph?

C - detritivore & heterotroph

what is the energy level from the kangaroo rat to the weasel shown in the food web above?

D - approximately the same as the energy transfer from the meadow mouse to the opossum

which group of organisms in the carbon cycle converts carbon into a form that is available to primary consumers?

D - producers * they take carbon energy and water and convert it into glucose

Explain how different fossil fuels form and how co2 is a byproduct of fossil fuel use from different sources

Methane: CH4+2O2 --> 2H2O+CO2 - when methane is oxidized, the 2 molecules produced are water vapor and co2 gas. the carbon found in the molecule CH4 was borrowed from a co2 molecule that was removed. when we burn natural gas, we return that carbon to the atmosphere in the form of co2. Peat: (partially decomposed plant material) - soil that forms peat is called histosol and a layer of peat is typically between 10 and 40 cm thick. when in the correct conditions, partially decomposed peat can be further transformed into coal. the C-H bonds hold a significant amount of energy ready to be released by burning. co2 is produced when fossil fuels are used Oil and natural gas: chemical transformations underground can produce other petroleum products. the dead remains of organisms in the water did not fully decompose at the bottom of the ocean and instead formed layers of sediments along with silt. petroleum products must be trapped and pooled under a non-porous rock. this kind of formation allows large quantities of useful gas and oil to collect together in a productive reservoir Coal: in order for coal to be used, it must be extracted from below the ground, which is why mining is necessary. coal is found in seams, where the layers of sediments were deposited, covered, and transformed. the C-H bonds hold a significant amount of energy and each hydrocarbon molecule is rich in energy ready to be released by burning.

Explain how some organisms can be both autotrophic and heterotrophic and what they're called.

Mixotroph: few plants and algae use a combination of different modes of nutrition

Species

a group of organisms that can interbreed and produce fertile offspring

Community

a group of populations living and interacting with each other in an area

The term species & population are used to describe closely related individuals. a) describe how diff populations may be formed from members of the same species b) over time a population may evolve features that distinguish it from other populations of the same species. suggest why the populations are still classified as the same species

a) different populations can be formed from members of the same species bc a species of animal may live in two very different areas; for example, rats found in Europe can be extensively found in America b) ?

Explain how carbon first enters an ecosystem's food web

all autotrophs convert co2 into organic compounds and carbon is constantly being cycled between living organisms and inorganic processes that allow the carbon to be available the carbon atoms that make up the cells of the flesh and flood of the giraffes, for example, came from the vegetation the giraffe ate.

Describe how cell respiration is involved in carbon cycling

cellular respiration from all trophic levels, including decomposers. producers co2 which is released back into the environment. this co2 diffuses into the atmosphere or into the water, depending whether the organism is terrestrial or aquatic

Explain why biomass also diminishes with energy along food chains

chemical energy is held in molecular bonds. therefore as energy is lost between trophic levels it is natural for biomass to be lost too. - biomass is usually measured as the total dry mass of organisms

Explain how chemical energy is obtained and used by consumers

chemical energy is obtained by the consumption of plants, or animals that have consumed plants

Ecosystem

community of living organisms and the physical (non-living) components of their environment

Detritivore

eat non-living organic matter. they eat dead leaves, feces, and carcasses

Explain the differences between the way energy flows and the way nutrients are cycled in ecosystems-be specific!

energy flows linearly; nutrients are cycled. Energy - energy enters from sunlight - autotrophs capture sunlight - energy transfer is 10% from one level to the next Nutrients - nutrients cycle within ecosystems - nutrients from weathering of rocks enter ecosystem - nutrients recycled from decomposition of dead organisms

Apply the laws of thermodynamics to energy flow in ecosystems

energy passed through trophic levels is only 10%. energy not passed onto the following organism is lost to heat energy (cell respiration). material not consumed, assimilated/digested/excreted.

Explain the correlation between rising atmospheric concentrations of co2 since the Industrial Revolution 200 years ago and average global temperatures

ever since machines replaced hand tools, humans have produced increasing quantities of co2 from factories, transport, and other processes using fossil fuels (coal and oil). over time, human activities have produced enough co2 to considerably raise the percentage of this gas in the planets atmosphere.

Define food chain

food chains show the flow of energy through the trophic levels of a feeding relationship

How many trophic levels are food chains usually limited to, and why?

most food chains contain 3-6 organisms because as the trophic level increases, the biomass and energy available decreases

list 3 examples of what the cells of living organisms use energy released by respiration for

movement, active transport,

Biosphere

narrow belt around the Earth containing all the Earth's living organisms

Explain how certain marine organisms contribute to carbon cycling

organisms living in water produce co2 through cellular respiration as co2 is dissolved in the water, it forms an acid. the pH of water decreases as the amount of co2 increases

Population

organisms of the same species living in the same geographical area

state two energy conversions that living organisms can carry out

photosynthesis & cellular respiration

Describe the role of photosynthesis in energy flow

photosynthetic organisms take simple inorganic co2 and convert it into energy-rich sugar, C6H12O6. the addition of minerals allows producers to synthesize complex molecules

Explain how the greenhouse effect works

refers to a planet's ability to use its atmosphere to retain heat and keep warm even when no sunlight is hitting the surface. it is only when sunlight hits an object that some of its energy is transformed into heat. heat energy (infrared radiation) has longer wavelengths than energy in the form of light - c02 --> estimated lifetime of 50-200 years in atmosphere. not very reactive unlike methane. - water vapor --> clouds - methane --> much greater potential to warm but has short lfifetime - nitrogen oxides --> released naturally by bacteria

outline how energy can be lost between trophic levels

respiration, excretion, lost in the environment (like through parts not eaten)

Describe the albedo effect and the type of wavelengths are associated with it

the ability a surface to reflect light. light-colored objects have high albedo, so very little light is absorbed and objects don't heat up as much as dark objects. dark colored substances have low albedo and absorb lots of light and convert it into heat.

explain how the flow of energy in a food chain or web differs from the movement of nutrients

the flow of energy is derived from the sun and flows linearly. the movement of nutrients however is constantly being cycled/recycled

Define trophic level

the position an organism occupies in a food chain

Relate limestone formation to the concept of carbon sequestration

the process of taking carbon out of the environment and 'lacking it up' in a substance for an extended period of time is called carbon sequestration, and when it happens naturally it is called sequestration. this is one way balance is maintained in the carbon cycle. microscopic eoraminifera shells have accumulated in sediments and when sediments go through the process of lithification, they form limestone.

Correlate biosequestration to the C cycle and other sources besides limestone

through biosequestration, an accumulation of furaminifera shells as sediments at the bottom of the ocean can trap carbon in limestone for millions of years. when cement is made by humans the carbon is released back into the atmosphere as co2, cancelling out the biosequestration.

Explain what can happen when/if species become reproductively isolated

two or more of the species can mate and produce a new population reproductively isolated from the original population. The new population may end up with different frequencies of certain alleles for a trait.

Provide examples of how global temperatures and climate patterns are influenced by concentrations of greenhouse gases

volcanic activity and particles suspended in the air, the quantity of radiation from the sun, the position of the continents, oscillations in ocean currents, fluctuations in Earth's orbit and the inclination of its axis.

Explain where methane comes from and how it enters the C cycle

when methanogenic " " metabolize food, they produce methane as a waste gas. methane is the main ingredient for natural gas. when methane is oxidized, the 2 molecules produced are water vapor and co2 gas.

discuss how and why most ecosystems rely on a supply of energy from sunlight

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