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Bio Exam 2 Study Practice Objectives
Terms in this set (41)
Explain why trophic levels are pyramidal.
Trophic levels are pyramidal because as one gets closer to the top there is less energy available thus it can only support so many, whereas lower on the pyramid has more energy and thus can support more organisms.
Why are biomass and energy availability lower in the higher trophic levels.
Energy is used at each level to maintain each level (species) own growth. Some energy is also lost when converted to different forms. So the next level does not obtain as much energy from the prior level.
With less energy at higher trophic levels, there are usually fewer organisms as well. Organisms tend to be larger in size at higher trophic levels, but their smaller numbers result in less biomass. Biomass is the total mass of organisms at a trophic level.
Why is there a limit to the number of trophic levels in an ecological pyramid.
There is a limit to the number of trophic levels because of the limit on energy. If there is a bigger base in the pyramid it can support more levels. About 90% of the energy entering the system is lost between each tropic levels and after a certain number of levels, there's not enough energy for that group to be viable.
there is only enough food for a few top level consumers, but there is lots of food for herbivores lower down on the food chain. There are fewer consumers than producers.
Define trophic level, explain its relevance to energy pyramids
Trophic level is each level in the food chain. For example: primary producers, primary consumers, secondary consumers, tertiary consumer. This effect produces an energy pyramid because less and less energy & biomass is available per trophic level.
A trophic level is the group of organisms within an ecosystem which occupy the same level in a food chain. ... The second trophic level consists of herbivores, these organisms gain energy by eating primary producers and are called primary consumers. Trophic levels three, four and five consist of carnivores and omnivores.
explain the basic structures of food chains and food webs
a food chain is a linear sequence of organisms through which nutrients and energy pass: primary producers, primary consumers, and higher-level consumers are used to describe ecosystem structure and dynamics.
Food web is a graphic representation of a holistic, non-linear web of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics.
A food chain outlines who eats whom. A food web is all of the food chains in an ecosystem. Each organism in an ecosystem occupies a specific trophic level or position in the food chain or web
Be able to draw a basic biogeochemical cycle for carbon, nitrogen, phosphorus, and water.
In Module 2 Class 2
water - starts in atmospheric level and is then precipitated down , kept above ground in lakes , stored in plants , drunk by animals . but some is absorbed and used as ground water . the water is then used biologically and disposed of . the water evaporates , condenses , and is precipitated down again in a lesser amount (mostly)
carbon - found in all organisms (building block of cells and life) where pollution , terrestrial photosynthesis , emissions from burning fossil fuels , weathering of rocks and more processes dispose of carbon dioxide in the atmosphere . carbon also is kept in the ground (decomposition of organisms and weathering) as soil carbon which can stay in the ground as fossil carbons , transformed by microbial respiration (or taken as humans for energy) , and composed into run-off
nitrogen - biologically done through the 3 processes of (1) ammonification , (2) nitrification , and (3) denitrification .1) nitrogenous waste is converted from dead animals into ammonium2) nitrifying bacteria converts ammonium into nitrites , and then again into nitrates3) bacteria convert the nitrates into nitrogen gas which is released back into the atmospherecycle : nitrogen fixing bacteria take nitrogen (N2) from the air an into ecosystems , then when animals die and decompose the necessary process (1 , 2 , 3) occur which release the nitrogen back into the environment . simultaneously , humans use nitrogen in fertilizers that are run off into marine and aquatic ecosystems . the nitrogen in the marine food webs are processed (2 , 3) to be released back into the atmosphere , but some lies as sediment on the bottom of these ecosystems
phosphorous - weathering can erode phosphates found in minerals , releasing it into the environment (or as aerosol in the air) where its run off and deposited as sediment in marine ecosystems and geologically uplifted . also , phosphorous is used as fertilizers for human development , and is run off into marine ecosystems and present in agricultural cycling
Understand what kind of research is conducted within the discipline known as ecology.
ecology - the study of interaction between organisms and their environment
ecology is studying organisms and how biotic and abiotic factors influence their way of living and how they interact with other organisms
Ecologist tend to work at the higher levels of the biological hierarchy generally from organism through ecosystems.
Within the discipline of ecology, researchers work at four specific levels, sometimes discretely and sometimes with overlap. These levels are organism, population, community, and ecosystem.
For example: Behavioral ecologist, soil ecologist, evolutionary ecologist, aquatic ecologist, microbial ecologist.
ecological research methods include observation, experimentation, and modeling.
define and identify the ecological unit known as an ecosystem.
An ecosystem is composed of all the populations of all organisms of an area plus the physical environment which they live.
An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. ... Biotic factors include plants, animals, and other organisms. Abiotic environment is like rocks.
The abiotic environment consist of a physical characteristics of the area.
The biotic environment is composed of the resident organisms.
composition of populations of various organisms as well as their interaction with their abiotic and biotic environments
ecosystem is lower than community
state the first and second thermodynamic laws and explain how they influence energy use and availability within an ecosystem
1st Law: The amount of energy in the universe is constant it can be moved and change to different forms but it cannot be created nor destroyed.
2nd Law: With every transfer of energy there is some energy lost as heat.
This explains how there are pyramids because energy is lost from one level to the next. The top level within the ecosystem receives the lowest amount of energy and biomass.
describe why energy flows through ecosystems and nutrients cycle.
Nutrients cycle because they are taken in, released from all organisms, recycled, and reused. It is a continuous process where the nutrients re-enter the soil through decomposition and start the cycle again.
Energy flows because of the 1st law of Thermodynamics. It states that energy cannot be created or destroyed, but it can flow from one form to another.
Energy is not recycled during decomposition, but it is released.
energy flows : because energy starts from a finite point (sunlight) and moves through trophic levels upward , energy decomposes on the way (organisms die or poop) ; which gives energy back to the producers and continues to flow through the ecosystem through the food chain
nutrients cycle : completely abiotic (through minerals / weather etc) that are extracted from their abiotic state by organisms (whether animals or bacteria) for metabolic functions . the organisms then excrete the nutrients back into the ecosystem that then gets converted / moved / treated abiotically to be used again
describe the relationship between energy flow and nutrient cycling.
The relationship between these processes is that energy from the sun gives energy to organisms that allow their nutrients to cycle. Without energy life and nutrients would not exist.
As matter cycles and energy flows through living systems and between living systems and the physical environment, matter and energy are conserved in each change. The carbon cycle provides an example of matter cycling and energy flow in ecosystems.
energy flow retains nutrients and disposes of them .
- nutrients are needed for organisms to carry out metabolic functions . without them , energy would be useless and vice versa . energy flow is the machine that provides organisms with capability of using nutrients and disposing of them when the process is finished . the nutrient is not changed (chemically) but its state after may differ from its initial state
Explain why the sun is the ultimate source of energy for nearly all ecosystems and how its energy is made available to all organisms within an ecosystem.
The first law of thermodynamics states that energy cannot be created. So photosynthetic organisms have to be able to convert solar energy into usable chemical energy so they can start the beginning of the food chain as producers (autotrophs).
Producers such as plants, algae, and cyanobacteria use the energy from sunlight to make organic matter from carbon dioxide and water. This establishes the beginning of energy flow through almost all food webs.
Define and identify the ecological unit known as a population.
Population: a group of organisms of the same species interacting together in a same particular area.
Discuss how each of these variables influences population growth: age structure, sex ratio, and population distribution
Sex Ratio: Population is dependent on the limiting sex, so if there are less females than males the population could decline.
Age structure: influences the population because at different stages of life you may or may not be able to produce offspring. You need to be in the reproductive stage of life. You can not be too young or too old.
Population distribution: A member of a low-density population—where organisms are sparsely spread out—might have more trouble finding a mate to reproduce with than an individual in a high-density population
Use population size, number of births, and number of deaths to calculate per capita growth rate (r).
G = rN; (r) is equal to the per capita birth rate (b) minus the per capita death rate (d), so r = b - d. (N) is equal to the total number of individuals
Describe exponential growth, including the curve shape, the circumstances under which exponential growth might occur, and the equation for calculating future population size.
if something is increasing exponentially, the quantity present gets larger faster with each increment of time. Populations can grow this way if they have unlimited resources. G = rN
Define carrying capacity (K) and explain how it limits population growth.
carrying capacity (K): represents the maximum population size that a particular environment can support; The number of individuals will get to large and the resources will become limited eventually the growth rate will plateau or level off. Graph shoots up then levels offs.
Describe logistic population growth, including the curve shape, the circumstances under which logistic growth might occur, and the equation for calculating future population size.
Logistic growth cannot continue indefinitely. Graph Oscillates around carrying capacity. G=rN((K-N)/K)
Define density-independent and density-dependent factors. Explain how each can influence population growth.
Density Dependent: affect individuals differently depending on population size; More linked/sets carrying capacity
Ex: Food, Disease, Predation (interspecific)
Density independent: affect all individuals the same no matter what the population is; Limit population growth, but not depended on size of population
Ex: Natural Disasters, Weather
Describe Type I, Type II, and Type III survivorship curves and explain how these different survivorship curves influence the type of growth a given population experiences.
Type 1: a high percentage of offspring survive their early and middle years, while death occurs predominantly in older individuals. These types of species usually have small numbers of offspring at one time, and they provide a high amount of parental care to ensure their survival.
Type 2: the probability of death is equal for all age classes in these organisms. Some of the animals also may have relatively few offspring and provide significant parental care.
Type 3: very few of these organisms survive their younger years; however, those that make it to an old age are more likely to survive for a long period of time.
Explain why human population growth appears to be exponential and the implications of this for future population growth.
Humans are unique in their ability to alter their environment with the conscious purpose of increasing the carrying capacity for humans. This ability is a major factor responsible for human population growth and a way of overcoming density-dependent growth regulation.
Define intraspecific interaction and describe how intraspecific competition influences carrying capacity and can lead to speciation.
Intraspecific interactions: Interactions between individuals of same species. Competition between the same species ed for the same resources limits these resources and individuals therefore, causing there to be a carrying capacity
Speculate about how interspecific interactions might affect both community structure and the evolutionary history of species within the community. (For example, how might the growth of two competing species be influenced if one of the species develops a mutualistic relationship with a third species?)
In interspecific competition, members of two different species use the same limited resource and therefore compete for it. Competition negatively affects both participants (-/- interaction), as either species would have higher survival and reproduction if the other was absent.
Define and identify the ecological unit known as a community.
Community Ecology is concerned with how species interact with each other and what processes determine the patterns of species coexistence, diversity, and distributions.
Describe the five factors that influence community structure: interactions (inter- and intraspecific), abiotic factors, resource availability, adaptive traits, and patterns of population growth.
interactions - both
inter and intraspecific interactions are present in a community . competition , predation etc all influence community structure and
abiotic factors - weather , forest fire , temperature all act as limiting elements for organisms in a population which require adaptations , migrations , or other necessary changes
resource availability- identifies level of competition which could progress certain organisms higher along than other organisms
adaptive traits - among similar species (or coevolution) organism that better adapt to handle changes in community structure will be best prepared for survival
patterns of population growth - random , clustered , or patterned
Understand interspecific interactions and list the various types of interactions.
intraspecific interactions occur between members of the same species
interspecific interactions occur between members of different species . populations with negative interactions among either one can help or hinder successful population growth
Mutualism parasitism presentation competition
Describe the following interactions: commensalism, mutualism, competition, predation, and parasitism. Give examples of each. Recognize that each may occur between different species or among members of the same species.
Commensalism: A commensal relationship occurs when one species benefits (+) from the close, prolonged interaction, while the other species neither benefits nor is harmed (0) Birds nesting in trees provide an example of a commensal relationship. The tree is not harmed by the presence of the nest among its branches. The bird, on the other hand, benefits greatly.
Mutualism: where two species benefit from their interaction (+,+). For example, termites have a mutualistic relationship with protozoa that live in the insect's gut . The termite benefits from the ability of bacterial mutualists within the protozoa to digest cellulose. The protozoa and their mutualistic bacteria benefit by having a protective environment and a constant supply of food from the wood chewing actions of the termite.
Parasitism: A parasite is an organism that lives in or on another living organism and derives nutrients from it. In this relationship, the parasite benefits (+), but the host (who is being fed upon) is harmed (-). The host is usually weakened by the parasite as it siphons resources. The parasite, however, is unlikely to kill the host, especially not quickly, because this would allow no time for the parasite to complete its reproductive cycle by spreading to another host.
Amensalism: any interaction between individuals of different species in which one individual is harmed (-) while the other individual is not affected (0). For example, as you walk down a sidewalk on a rainy day, you step on an earthworm. The earthworm is negatively affected, and you are not affected at all
Define niche. Explain how resource partitioning can reduce competition among species that would otherwise occupy the same niche.
How a species fits into its environment and community. For a species to survive in an area, a certain combination of ecological variables are necessary, including resources (light, nutrients, food, and habitat), environmental characteristics (temperature and water availability), and interactions with other organisms.
resource partitioning: when species utilize limited resources (among competition) without driving one to extinction
if a population evolves to make use of a different resource, a different area of the habitat, or feeds during a different time of day allows organisms to coexist by minimizing direct competition.
lessens the effect of competition , which also alienates organisms that may have similar niches in their environment . it prevents occupation of the same niche that would drive on species to extinction
Learn how interspecific interactions can change the carrying capacity for populations, and change energy flow and nutrient dynamics in ecosystems.
Keystone Species: A species whose effect on community structure is greater than its biomass.
Ex: beaver builds a dam...changes dynamics and new habitat
it can have a drastic effect on community as a whole or things like glaciers or lava that change the environment so that it is no longer at equilibrium
predation , competition , and all negative interspecific interactions will successfully lower the carrying capacity for the respective species . competition will lower that of both , but predation will cause an oscillating change among both organisms as each population becomes more extant
- mutualism , commensalism could raise carrying capacity of the species if benefiting reproduction and survival
- energy flow and nutrient dynamics will become varying among certain interactions . when predation of herbivores is at a high , there will be more foliage for food available than herbivorous animals . it the fluctuate to when there is less foliage available and more animals present to induce predation . energy levels change as these interactions take their toll
Learn how changes in net primary productivity can affect interspecific interactions and carrying capacity for populations.
net primary productivity = gross primary productivity - (lost energy from metabolic production)
^ it is important to understand npp to evaluate the total amount of present energy that can be distributed to an ecosystem . determining npp can give an estimate of what carrying capacity , population growth , and other biological factors of individual ecosystems could be
Understand coevolution and describe an example.
coevolution - when the genetic changes or adaptations of one species reciprocally affect another's
example: garter snakes and rough skinned newts . predation of the newt by the snake led the newt to inhibit a toxin excreted from their skin when immense pressure was made . snakes developed a resistance to this toxin in order to maintain their major food source
Define primary and secondary succession and explain how both might influence community structure.
primary succession - new found land has been made , by an eruption most likely , which lays solid rock out in the open for weathering . weathering has broken down the surface enough to allow some phosphates or other nutrients to show . pioneer species (lichens) settle on these weathered parts and continue to reproduce / decompose and grow . the more broken down and nutrient extended rock allows for hardier plant species and more pioneer species , eventually to a forest / grassland ecosystem
secondary succession - a fire has completely burned down a forest , the remaining ashes allows nutrients for annual species and pioneer species to settle , then shrubs , and then the same taller trees of the forest dominate again in the original state until another disturbance is to come
Explore the consequences of nutrient enhancement for a biological community. Think about how increasing the nutrients for a community could be good. How would all levels of a community respond? Can having too much of a nutrient be bad for a community? How and what trophic levels are affected the most?
Increasing the nutrients could be good because there is more resources available. This would help the community bc there is less competition. but having too much nutrients is bad. For example it can have increased nitrogenous materials in soil. Plowing mixes soil, therefore speeding up decomposition of organic matter, taking oxygen, and releasing nitrogen. The top levels are affected the most because of biomagnification.
- producers use nutrients from the environment whereas consumers use the nutrients obtained from these producers
- an increase in the growth of these producers would disrupt the equilibrium in the community and have a varying effect .
^ effects include : increase in biomass , depleted oxygen level , and other community oriented effects
Apply your knowledge of community structure and population growth to understanding the structure and internal processes of an ecological community. Think about how interactions between individuals and species can affect the structure of the entire ecosystem.
a community is made up various trophic levels that compose a food web of organisms which an underlying niche . it is interspecific interactions and internal process of energy flow and nutrient cycling the inhibit population growth
ex : if one prey species reproduces more slowly than another , predator choices would be indicative of this
Learn about the interactions within an aquatic ecosystem.
Consider the food chain described in the "Nutrient pollution" simulation.
How do those organisms interact? Can this be applied to other freshwater systems? How?
different from those in terrestrial;
:dependent on primary producers to provide oxygen and nutrients to the respective organisms making up the food web , in an aquatic ecosystem there is less diversity of species (besides fish , plant life , etc) but among these species a large amount of diversity with incredible important of niches
Yes, for example producers are phytoplankton, and the primary consumers are zooplankton, secondary are trout, and then there is decomposers or detritivores/bacteria. Yes, this can also be applied to fresh water systems.
Generate hypotheses about the effect of increased nutrient availability on populations and communities of organisms.
The more phosphorus available the more that plants and algae can grow. These plants convert CO2 into O2. However, since the population of plants and algae increased so did the number of dead plants. The decomposers are then able to convert the dead O2 back into CO2. Therefore there is a decline in O2. Nitrogen is not a limiting factor and does not affect the phytoplankton population level.
increased nutrients in an ecosystem would cause an increase in the population of primary producers . this effect becomes gradually more effective to higher trophic levels , increasing the nutrient deposit and causing a varying effect
.- can inhibit extinction or population damage to communities
- can enhance primary producers in community having a positive effect (more food)
- can deplete oxygen and cause extinction of an entire community and poison all present organisms
Investigate the consequences (at the population and community levels) of altering nutrient levels, and nutrient flow through biogeochemical cycles. Can humans alter those cycles? Make some reservoirs larger or smaller than they are naturally? If so, how could this affect populations and communities?
Yes, humans can alter those cycles. Humans can do so through waste. For example humans may dump there waste.
at population level , altering nutrient levels could affect an organisms ability to retrieve energy in their ecosystem . as a producer there could be more competition , or as a higher level consumer there could be less food availability and more competition
at community level , there can be oxygen depletion and cycling of water and immense nutrients could cause imbalance in the community structures , leading to various negative effects
Define biological magnification and understand the mechanism whereby certain toxic chemicals become concentrated in organisms at the highest trophic levels. Understand why the levels of toxin are higher in higher trophic levels even while energy levels are lower in higher trophic levels.
Biological magnification is the increasing concentration of persistent, toxic substances in organisms as it moves through the trophic levels from the primary producers to apex consumers. The toxin level increases as you go up the trophic level bc toxin does not change and each level you go up they only take 10% of the nutrients. So at the top level, they have the smallest amount of nutrients and the highest amount of concentration of the toxin.
- a larger concentration becomes present as passed on because the nutrients are stored as an energy component in the higher level organisms . it is the amplified to have a larger effect as the organism continues to age and consume
Understand the threats posed to human health by consumption of organisms exposed to environmental toxins, and how biological magnification plays a role.
our diet of animals such as tuna and salmon , are high level consumers that also are capable of living a very long time . they can accumulate high levels of potent chemicals that have been released naturally and artificially for their entire life span . the combination of this potency from biological magnification and human impact makes these animals harmful for human consumption (birth defects , immune system deficiencies , chemical poisonings , etc)
Understand the difference between qualitative and quantitative data. Write down the definitions for these two types of data and then examples from today's classroom exercises. Practice more with these concepts by looking back at all the data you've collected in modules 1 and 2 and decide whether those data are qualitative or quantitative.
Quantitative data includes a numerical information and a quarter by taking measurements. For Ex: Population size, forearm length, species richness, etc.
Qualitative data are not numerical and consist of things that cannot be measured. identifying physical characteristics
For example: presence or absence of certain species, appearance, smell, and color, etc.
Identify and describe (in terms of net primary productivity, soil types, rainfall amounts, typical temperatures, and types of plants) the following biomes: grassland, tundra, forest, desert, and waterprovinces.
biome distinctions can be by NPP , climate , rainfall , temperatures , type of foliage
grassland - no tall trees , cold to hot temp , mid to high npp , moderate
tundra - freezing temp , low diversity , high precipitation mostly as snow , little foliage , low NPP
forest (deciduous vs coniferous) - deciduous forests fall below arctic circle , more diversity of plants and animals than coniferous, but still have lower temperatures and mid NPP (coniferous lower NPP than deciduous)
desert - little biodiversity , little rainfall , high temperatures , lowest NPP of all biomes due to harsh climate
water (lakes , marine , estuary , wetlands etc) - vast space give oceans low NPP , but highest diversity of all biomes . wetlands have mid NPP but garner highest human effect , estuaries are mid to high as well as lake and river environments but are proven to have more competition (freshwater resources and limited space)
2) define and identify the ecological unit known as a population
population - group of individuals in the same area belonging to the same species
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