Biology Module 2

Equation to calculate the number of individuals added to the population.

# of individuals added= r(population started with) r= per capita growth rate

Mutualism:

(+,+) both benefit

Parasitism:

(+,-) parasite benefits and host harmed

Predation:

(+,-) predator benefits and prey harmed

Commensalism:

(+,0) one benefits and other is neutral

Competition:

(-,-) harms both involved

Amensalism:

(-,0) one harmed other is neutral

Community dynamics:

a change in community structure and composition over time.

Nutrients move between pools via two broad categories of processes called _ and _.

abiotic and biotic. Abiotic process are purely physical or chemical in nature and don't involve living organisms (like the weathering of a rock). Biotic processes do required the intervention of something that is alive (frequently bacteria, archaea, or saprophytic fungi.

How is the fixation of nitrogen accomplished?

accomplished by a variety of soil and/or water bacteria (or industrialized humans)

Define ecological community:

an assemblage of populations of different species living together in the same area

Per capita birth equation:

b/N

Define the fixation of nitrogen:

changing it from atmospheric N2 into a form that can be taken up and used by living things.

Per capita growth rate could decline if there was _ for resources in a population.

competition

Define Ecosystem:

composed of all the populations of all organisms of an area, plus the physical environment in which they live.

Biotic Environment:

composed of resident organisms. energy flows through them and stops, but materials (nutrients) are reused over and over

Per capita death equation:

d/N

Define population ecology:

deals with the ecological processes of populations

As prey density is low, predator population _. As predators decrease, prey _.

declines, increase

Density-dependent:

density of the population at a given time affects growth rate and mortality (diseases, waste, predators)

Define exponential population growth:

describes growth that is unchecked by any constraining regulatory forces.

Natural populations are often _.

dynamic. Which means their size may change dramatically from year to year or over shorter time periods, depending on the species.

What is an example of an autotroph: a. an iris b. an oak tree c. deep sea sulfur bacteria d. both a & b e. all of the above

e. all of the above

Dynamics of all ecosystems revolve around two key processes:

energy flow and nutrient cycling

Where do we study ecology?

everything from atoms to the biosphere

1st Law of Thermodynamics:

Energy cannot be created or destroyed

Which of the following describes the second law of thermodynamics (according to quiz):

Energy is lost to heat during transformation between forms

If the per capita growth rate stays the same but the population changes increases, what will happen to the ending population size?

The ending population size will increase.

If the starting population size stays the same but the per capita growth rate increases, what will happen to the ending population size?

The ending population size will increase.

Where would the highest concentration of a chemical, such as mercury, be found?

The highest trophic level.

What do population ecologists study and what types of questions do they attempt to answer?

factors that determine how a population behaves

In an ecosystem, every _ and nutrients _.

flows, cycles

Characteristics of High Density:

higher breeding, higher competition

Niche definition:

how a species acquires the resources they need and where they fit into their environment relative to other organisms

Biomagnification:

increased chemicals in successive trophic levels.

Density-independent:

influence the morality regardless of population density (weather, natural disasters)

Define interspecific interactions:

interactions between member of different species.

Define infraspecific interactions:

interactions between members of different species

Characteristics of Low Density:

less breeding, less mortality

Nutrients are a _ factor.

limiting

Eutrophication:

naturally occurring in aging lakes, large number of producers, lack of oxygen (can also occur quickly when humans dump fertilizer and sewage into lakes)

Typical limiting nutrient in terrestrial systems:

nitrogen

Exponential growth model characteristics:

no limitations on population's growth because all necessary resources to survive and reproduce are in excess, the larger the population becomes then the faster it will grow

Define producer:

organisms that are able to convert solar energy to useable chemical energy

Define Secondary consumer:

organisms that feed directly on primary consumers

Define Primary consumer:

organisms that feed directly on producers

Define Tertiary consumer:

organisms that feed directly on secondary consumers.

Abiotic Environment:

physical characteristics

What makes up an ecosystem?

-Environmental factors (abiotic) and living organisms (biotic)

Characteristics of exponential growth:

-rapid growth -unlimited resources (can happen in our lifetime by invasive species- like a big snake that comes into Florida and takes over the swamp because it has no competition)

List 6 population characteristics you would want to know about if you were managing a population of an endangered species.

1. Population size 2. Age (and life expectancy) 3. Sex ratio 4. Growth Rate 5. Distribution 6. Limiting Factors

Give an example of some characteristics of the environment for a fox.

1. Water- a needed resource in its environment 2. Sun- gives energy to the plants and therefore the fox 3. Predators

Categorize grass, an owl, a snake, and mice into an ecosystem.

1. producer (grass) 2. primary consumer (mice) 3. secondary consumer (snake) 4. tertiary consumer (owl)

_% of energy is captured through photosynthesis.

1.3% to 1.6%

There are _ number of pools (reservoirs) for the atoms (nutrients) required by living organisms.

4- atmosphere, large bodies of water on the planet, the rocks and soil of the terrestrial areas of the planet, and the living organisms (biota) that inhabit it.

About how many percent of the atoms in a human are recycled hydrogen, oxygen, and carbon? What does this mean?

99% This means you could have atoms that were once in a tyrannosaurus rex. Also, all of the atoms in your body come from the food you've eaten.

Define population:

A group of organisms in a single species inhabiting the same geographic area.

non-point sources:

Agricultural runoff

2nd Law of Thermodynamics:

As energy is transformed, some of it is lost as heat.

Why is net primary productivity a good measure of the overall productivity of different ecosystems?

Because it's the measurement of what would be passed to the next trophic level.

What effects do high concentration of chemicals have?

Birth defects

How have humans doubled the amount of nitrogen available to plants and microorganisms?

By making industrial chemical reactions to bypass microorganisms when making chemical fertilizers. Most of this is applied to agricultural fields, laws, golf courses, etc. Much of this soil-dwelling bacteria can convert ammonia into nitrate which dissolves in water. Rainwater then leaches excess nitrate from the soil and carries it into aquatic habitats.

How does the net primary productivity relate to the number of trophic levels an ecosystem can support?

Eventually, the 10% that is passed into the next trophic level will not be sufficient to support life in that trophic level.

Define Detritivores and identify where in the food web you would find them.

Detritivores derive their energy from dead or discarded organic matter. You would find them with the decomposers in the food web.

What is the logistic population growth equation?

G= rN X (K-N)/K r= per capita growth rate K= carrying capacity Used by biologists to describe population growth when exponential growth is not possible. Has built into it a mechanism to alter the per capita growth rate as the population size increases. G= population growth per unit of time

Exponential growth is more likely for some species, what kinds?

Insects. They have a high population size, high reproduction rate, and short life spans.

What does "nutrients cycle" mean?

It means that the substance needed by living organisms (nutrients) move from the environment to organism, and then back to the environment. In order to do this, the nutrients undergo chemical transformations. These transformations are powered by energy flow.

Is a neutral interspecies found in nature?

No neutral and neutral

How does the 1st Law of Thermodynamics affect energy using the ecosystem?

Photosynthetic organisms convert solar energy to chemical energy and are then producers (autotrophs).

_ surge in population growth when extra phosphorus is available.

Phytoplankton

Give the formula for per capita growth rate (symbolized by r)

R= (b-d)/N b- birth rate (rate of addition to population) d- death rate (rate of loss to population)

Net primary productivity:

The total amount of energy which primary producers can pass on to the next trophic level. (Amount of energy in biomes) Group primary productivity - respiration = net primary productivity. Respiration: amount of energy an organism uses for cellular functions.

The reason the body of water runs out of oxygen to support aquatic life is:

The water becomes dense with algae due to increased phosphorus. The phytoplankton eventually die and sink to the bottom of the lank. The decomposers at the bottom of the lake have a lot of food because there is a ton of dead algae. They consume the available oxygen in the water and the water becomes anoxic (without oxygen) and the fish die.

How might a difference in the ratio of males to females lead to differences in the growth of two populations?

There is higher reproduction and therefore different growth rate potential. (age structure can also do this)

Define heterotroph. At what levels within an ecosystem will you find heterotrophs?

They are organisms that need to consume other organisms in order to gain energy. In the consumer levels.

Define autotroph. At what levels within an ecosystem will you find autotrophs?

They do not need to consume other organisms in order to gain energy. In the producer level.

Define Food chain:

pathway along which energy is transferred. sun -> producer -> consumer

Typical limiting nutrient in aquatic systems:

phosphorus

Define logistic growth:

population expanding until resources become scarce

Logistic Population growth model characteristics:

population growth is often limited by resources such as nutrients or space, which makes a carrying capacity, when population is small it may be exponential growth but then it will hit carrying capacity and level off.

Community definition:

populations of different organisms in one area

Primary succession:

process that occurs in an area originally without living organisms. newly exposed or newly formed land is colonized by living things. (ex. rock is exposed or formed from volcanoes)

Ecology at the level of the population is:

processes that act within populations (interactions between the same geographic area)

What does it mean if r=0, r>0, and r<0?

r=0: growth stays the same r>0: growth increasing r<0: growth declining

Define food web:

relationship among trophic levels that are more complex. can be connections between non-adjacent levels in the energy pyramid.

A limiting nutrient (such as nitrogen) causes:

restricted plant growth because its supply is exhausted before other nutrients.

Point sources of pollution:

sewage or industrial waste related directly into the ecosystem

Predicting population size formula:

starting size X growth rate = the change in population during that time

Define Thermodynamics:

study of energy and its transfer within physical matter

Define community ecology:

study of the interactions among populations living together in the same area.

Define succession:

succession describes the sequential appearance and disappearance of species in a community over time.

Chemicals in an ecosystem come from:

the air, water, soil, rocks, and other organisms.

What is a biogeochemical cycle?

the cycling of various materials and nutrients that is involved with the utilization of nutrients.

Define an ecosystem (according to quiz):

the interaction of living (biotic) and nonliving (abiotic) components

Secondary succession:

the process that occurs when existing ecological communities are disturbed and then allowed to return to their original state. part of an ecosystem is disturbed and remnants of the previous community remain. (a wildfire clears a forest, their nutrients return to the ground in the form of ash, thus the area will soon be ready for new life, annual plants begin to grow back, will eventually reach equilibrium where species is no longer changing and resembles the community before the fire)

Define coevolution:

the reciprocal genetic change over time of two or more interacting species and can take many forms. (like the frogs changing their song because the bats and mates are attracted to it)

Define ecology:

the study of interactions between biotic and abiotic components

Define carrying capacity:

the upper limit to population size, the maximum population size that can be supported over a long period of time.

Gross primary productivity:

total amount of energy captured by photosynthetic organisms.

What are the four nutrients most important to living ecosystems?

water, carbon, nitrogen, and phosphorus.