Lisa Numann - Topic 4

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Topic 4

4.1.1 Define ecology

ecology: study of relationships between living organisms, and between them and their environment.

4.1.2 Define ecosystem

ecosystem: a community and its abiotic environment

4.1.3 Define population

population: all of the same species in an area.

4.1.4 Define community (i) community: all of the living populations in one area.

4.1.5 Define species

species: any group of organisms that can mate and produce fertile offspring.

4.16 Define habitat

habitat: environment in which a species normally lives or the location of a living organism.

4.1.7 Explain what is meant by a biosphere.

a biosphere includes all of the biomes of the earth.

4.1.8 Describe what is meant by a food chain giving three examples, each with al least three linkages.

food chain: simple diagram showing passage of energy from one organism to another.
producers are found at the bottom – followed by primary consumer – then the secondary consumer
arrows convey direction of energy being passed
only 10% of energy is passed from organism to organism.

4.1.9 Describe what is meant by a food web.

food web: more detailed diagram involving all organism involved in passage of energy.
Arrows convey predator receiving the energy

4.1.10 Define trophic level

trophic level: level at which an organism feeds in a food chain/food web.

4.1.11 Deduce the trophic levels of an organism in a food chain and a food web.

4.1.12 Draw food web given appropriate information, containing up to 10 organisms.

4.1.13 Define autotroph/producer

plants produce the energy for the ecosystem through photosynthesis

4.1.14 Define heterotroph/consumer

animals, some protists/fungi/bacteria depend on other for their food

4.1.15 Define detrivore

detrivore: an organism that ingests dead organic matter and digests it internally.

4.1.16 Define saprotroph

saprotroph: an organism that feeds on dead organic matter using extra cellular digestion
example: bacteria and fungus

4.2.1 State light is the ultimate energy source for all communities.

4.2.2 Describe energy conversion from light to chemical.

light is converted from chemical to energy when the photons hits the photosystems in the chloroplast.

4.2.3 State that white light is composed of various wavelengths, thus colors.

4.2.4 State that chlorophylls (a&b) are the main photosynthetic pigments.

4.2.5 Outline the differences in absorption of red, blue and green light by chlorophylls.

pigments absorb colors due to their structure.
the colors that are not absorbed are reflected
the reflected color is the one observed

4.2.6 State that the function of light energy is to split water and make oxygen and hydrogen while also making ATP.

4.2.7 State that ATP and hydrogen are used to fix carbon dioxide and make glucose after the photolysis of water.

4.2.8 Explain photosynthesis can not be monitored by the production of oxygen, carbon dioxide decrease, or the increase in biomass.

the input and output of gases can be measured by
a change associated with these is the change in pH
As an organism grows its biomass increases
Measuring the increase in biomass gives us a measurement of net productivity

4.2.9 Outline the effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis.

Temperature does not affect rate of reaction because the energy that drives the reaction is supplied by light, not heat.
as light intensity increases, so does the relative rate of photosynthesis
increase lasts until a certain point when the curve levels out
carbon dioxide is similar to the light intensity condition as chloroplasts are dependant on light intensity.

4.2.10 State respiration involves the breakdown of organic molecules to release energy stored by photosynthesis.

4.2.11 State that carbon dioxide fixed by photosynthesis is released by respiration.

4.2.12 State that energy released during respiration of complex compounds in an organism is used within an organism to do work or is lost as heat.

4.2.14 Explain biomass and energy transfer in a food chain in terms of growth, respiration, cell activities and waste.

primary productivity: rate at which producers covert light energy into chemical energy
gross primary productivity: total amount of chemical energy incorporated into producers.
producers use energy for growth and cell activity
conversion of organic compounds to ATP is necessary for energy for their needs
energy is finally lost as heat.

4.2.15 State that when energy transformation takes place the process is never 100% efficient.

efficiency is commonly 10-20%

4.2.16 Explain what is meant by a pyramid of energy and reasons for its shape.

pyramid of energy is drawn to represent the proportions of energy
only 10% is passed on to each level

4.2.17 Design a pyramid of energy given appropriate information.

4.2.18 Explain that energy enters and leaves an ecosystem but energy must be recycled.

energy can come in the form of light energy into a ecosystem
energy leaves in the form of heat
elements never leave but are cycled between living organisms, for example:
carbon
hydrogen
oxygen
nitrogen

4.2.19 Draw the carbon cycle: photosynthesis, respiration, combustion and fossilization. (given in order)

carbon dioxide in atmosphere
producer: photosynthesis and respiration
consumer: rspiration
death of an organism
decomposer
fossilization and rock formation
fossil fuels
combustion
returned to atmosphere

4.2.20 Explain the role of saprotrophs (decomposers) in returning elements to the environment in an inorganic form.

bacteria and fungi form basis of food web
they are ultimate organisms that decay dead organisms
they return the nutrients back to the soil to be recycled in ecosystem

4.3.1 Define evolution

evolution: the process of cumulative change in the heritable characteristics of a population.

4.3.2 State that populations tend to produce more offspring than the environment can support.

sigmoid growth curve: S-shaped graph that shows the population growth through the following phases:
lag phase
log phase
decline/death phase

4.3.3 Explain that the consequence of potential overproduction of offspring is a struggle for survival.

the more offspring in a population the more competition there is for survival.
Some offspring have traits that allow them to have an advantage in obtaining food or hiding from its predator.
Natural selection supports favorable traits.

4.3.3 State that the members of a species show variation.

4.3.4 Define carrying capacity

carrying capacity: maximum number of a species that can be sustainably supported by the environment.

4.3.5 Explain how sexual reproduction promotes variation in a species.

during metaphase 1 of meiosis the homologous chromosomes line up and form independent tetrads
independent assortment allows for infinite variation
an increased chance of variation is due to crossing over of alleles for a trait
mutations also contribute to variations of various traits

4.3.6 Explain how natural selection leads to the increased reproduction of individuals with favorable traits.

some phenotypes for a trait within a species are more favorable for survival than others
nature chooses the favorable form
possible causes

- camouflage

4.3.7 Discuss the theory that species evolve by natural selection.

evolution is the change in the heritable characteristics of a population over time.
when the gene frequency for a favorable trait changes evolution occurs
example: moths
before Industrial Revolution peppered moth was light colored to blend with lichen on specific tree bark
after the Industrial Revolution pollution created turned the tree bark black and the moths experienced natural selection
the gene frequency for dark moths increased
the gene frequency for the light moths decreased
conveys evolution of a species overcoming harmful environment

4.3.8 Explain the two examples of evolution in response to environmental change, including multiple antibiotic resistance in bacteria.

peppered moth (see above)
bacteria
bacteria have either ½ cell walls for protection
antibiotics usually attack building of a bacteria’s cell wall
bacteria contain genes in their plasmids for being resistant to specific antibiotics
rapid mutation of bacteria allows them to become resistant to specific to antibiotics they were not originally resistant to
a change in gene frequency then occurs
example of current evolution.

4.3.9 Explain how, by natural selection, the best-adapted will survive to breed.

nature selects the variation that best suits the ecosystem
variations dominate species because more of that variation will survive to breed and produce.

4.4.1&4.4.2 Outline 3 examples of local global issues of human impact causing damage to an ecosystem or the biosphere.

green house effect
natural phenomenon but enhanced by humans
gases in atmosphere insulate earth and have ability to trap long wave radiation
humans have added to amount of gas
long wave radiation is trapped in our atmosphere, increasing temperature of our atmposhere
Ozone layer
ozone is molecule made of 3 oxygen atoms
ozone filters out radiation
CFCs react with ozone, forming pairs rather than O3
this allows radiation to harm earth’s surface

(iii) Acid Rain

4.4.3 Discuss measure, which could be taken to contain/reduce the impact of human impact issues.

green house effect: reducing amount of fossil fuels being burned, reducing deforestation, planting more trees
ozone: change in legislation to reduce CFC emission, exhaust filters, alternative chemicals

4.5.1 Describe one method to measure abiotic characteristics of light.

light intensity and amount of energy available for production and timing of seasonal cycles
a light meter can be calibrated to either lux or foot-candles. 
Relative luminance may be expressed as percent transmittance in that habitat.

4.5.2 Define random sample

random sample: a method to ensure that every individual in a population has an equal chance of being observed. 

4.5.3 Describe on technique used to estimate the population size of one animal based on “mark and recapture”

Lincoln index: population size = (n1 x n2) / n3

4.5.4 Describe one method of random sampling used to compare the population numbers of two plant species based on quadrat methods

square frame = quadrat
quadrat represents species
number of individuals counted

4.5.5 Evaluate graphical representations of ecological data.

prey number rises then predators number rise
prey number drops leading the predator to drop
factors include
competition for food in winter
chaos theory: small changes have long term effects
prey/predator theory mentioned above

4.5.6,4.5.7&4.5.7 Define mean, mode and median.

mean: average
mode: most common number
median: center number

4.5.9 State that the term standard deviation is used to summarize the spread of data around the mean and that 68% of the values must fall within one standard deviation of the mean.

4.5.10 Calculate the means and standard deviation of frequency distributions.

4.5.11 Describe how standard deviation is useful in comparing the means and spread of ecological data between two or more sites.

small standard deviation: data is also close to mean value, nor much variety
large standard deviation: lots of variety in data