Communities and Ecosystems

Describe community: populations living and interacting with each other

Describe what interspecific means: relationships that occur between species

Describe and provide example for herbivory: Primary consumer (herbivore) feeding on producer (plant); white tailed deer eating clover

Describe and provide example for predation: Consumer feeding on another consumer; canadian lynx and snowshoe hare

Describe and provide example for interspecific competition: Members of specific species compete for resources; white tailed deer and cottontail rabbit both eat clover

Describe and provide example for parasitism: one organism feeds on or off of another and does harm to the other; tapeworm in cow intestines

Describe and provide example for pathogenicity: microorganism capable of causing disease in its host; influenza virus, candida fungi

Describe and provide example for mutualism: two species living together that both benefit from; bees and flowering plants

Describe the mutualistic relationship between zooxanthellae and coral: coral provides fungi with location to grow, zooxanthellae provide coral with food to make calcium carbonate

Describe the mutualistic relationship between root nodules and legumes: bacteria provides legumes with nitrates by converting atmospheric nitrogen into compounds usable to plants, legumes provide bacteria with organic compounds

Describe the mutualistic relationship between fungi and orchids: fungi provides orchid roots with nutrients

Describe invasive species: any plant, animal, or microorganism that is introduced to an ecosystem outside its native range and has potential to cause harm

Outline why invasive species become problematic:

lack natural predators,

Little competition

Rapidly spread

Harm endemic species

Reduces native biodiversity

Describe an animal example of an invasive species: burmese python in Florida everglades, eats mammals, birds, reptiles

Describe an plant example of an invasive species: kudzu, intentional human introduction, decreases soil erosion, fast growth and covers other plant species

Describe the purpose of Chi Squared: shows associations between species

Be able to analyze Chi Squared results on association if given information on calculated Chi squared value and critical value in chart

State the confidence level (p value) used in biology Chi squared: 95%

State when to reject the null hypothesis in Chi squared (answer should include information on relationship between Chi Squared Value and critical value): if the calculated Chi squared value is higher than critical value

Distinguish between top down and bottom up factors in communities: top-down factors are controlled by consumers and predators, bottom-up factors are availability of resources at lower trophic levels

Describe allelopathy in plants: the release of chemical inhibitors by plant, preventing growth of competitors

Describe the use of antibiotics by some plants: kill off bacteria in the soil around them preventing disease

AHL Material-HL students only

Describe ecological succession: progression in communities over time

Describe climax community: succession has ended and most stable ecosystem for biome conditions had been reached

Be able to draw primary succession (not on test though, but could be on IB exam)

Distinguish primary and secondary succession, then provide an example of each: primary succession starts on lifeless new land, secondary succession starts on existing soil affected by disturbance

Back to Core Material (SL and HL Students)

Describe ecosystems: multiple communities interacting with their nonliving environment

Describe what an open system means which reference to an ecosystem: open system takes into account abiotic factors, involved the transfer of energy and nutrients

Describe an autotroph: autotrophs synthesis organic molecules from simple inorganic substances in the environment

Describe a heterotroph: obtains organic molecules from other organisms

Distinguish between a saprotroph and detritivore: detritivores are organisms that ingest non-living organisms, saprotrophs secrete digestive enzymes and absorb decaying organic matter

Describe a mixotroph: organisms that are able to both create their own food and gain energy from other organisms

Describe the purpose of arrows in food chains / webs: shows the transfer of energy between organisms from feeding

Be able to create a food chain with at least 3 linkages

Describe trophic level: position an organism occupies in a food chain

Describe a food web. A diagram showing how food chains are linked together into complex feeding relationships.

shows a community relationship

multiple producers

Describe how omnivores can occupy multiple trophic levels in food web. Omnivores consume organisms from all levels of the food chain (plants and animals)

Be able to identify trophic levels of organisms in food chains/webs

Describe a pyramid of biomass

Describe why there is less biomass in higher trophic levels

Higher trophic labels have less biomass

Nutrient transfer is not efficient

Expend lots of energy hunting prey

consume large quantities to stay healthy

Less top carnivores

Describe biomass. Biomass: total dry organic matter of living organisms or ecosystems.

State unit of biomass. g m-2 yr-1

Describe productivity. Rate of generation of biomass in ecosystem

Distinguish between gross production and net production.

Gross production: total amount of organic matter produced by plants.

Net productivity: amount of energy available to primary consumers after respiration has occurred.

State the initial source of energy for most ecosystems. Light is the initial source of energy for almost all communities.

Describe a chemoautotroph. Chemoautotrophs use inorganic compounds in limited light environments.

State the approximate amount of energy transferred to each trophic level. Only approx 10% of energy is passed from one trophic level to the next

List the ways energy is lost in an ecosystem.

heat

cellular respiration

feces

unconsumed

State the unit for the pyramid of energy. kj m-2 year -1

Describe reasons for the shape of the pyramid of energy. Graphical representation of the amount of energy of each trophic level in a food chain

Explain how energy and nutrients/carbon move through an ecosystem. (6 marks)

The sun provides light as the initial form of energy. Autotrophs/producers convert it into chemical energy through photosynthesis. Only 10% of energy transfers from one trophic level to the next; rest is lost as feces, unconsumes, cellular respiration, or heat. energy is not recycled once it reaches the highest trophic level. However, nutrients/carbon molecules are recycled. They are transferred through levels by feeding, each higher level requiring more. Saprotrophs help recycle through decomposition, giving nutrients back to producers.