C4.1-C4.2

Population

a group of individual organisms of the same species living and interacting in the same area

Random sample

every member of a population has an equal chance of being selected for the sample

Sampling error

difference between the true and estimated value

Quadrat

a frame that is a fixed size and used for random sampling; good for sessile (immobile) organisms; mark the boundary, generate random numbers, stddev indicates the degree of variability

CMRR

Capture, Mark, Release, Recapture; used for counting motile organisms

Lincoln index

M*N/R; M = # of marked, N = # of recaptured, R = # of recaptured with marks (caught twice)

Carrying capacity

maximum population size that an environment can support; b/c limited resources which promotes competition

Negative feedback control

populations might rise and fall periodically, but are relatively stable over time

Density-independent

factors that have the same effect no matter the population size; Ex. natural disaster

Density-dependent

factors that have an increasing effect when the population is bigger; Ex. competition, predation, diseases/parasites

Positive feedback

reproduction causes exponential growth; occurs when density-dependent factors are not effective or movement into a new niche where resources are abundant

Community

several populations living together

Intraspecific relationship

relationship between individuals of the same species

Intraspecific competition

Leads to natural selection because some individuals have traits that help them outcompete others; compete for territory, mates for reproduction, etc.

Intraspecific cooperation

mutually beneficial relationship; group hunting/foraging, defense against predators, parenting, etc.

Interspecific relationship

relationships between different species

Interspecific herbivory

primary consumers eating primary producers; may or may not kill the producer;

Interspecific predation

one species kills and eats another species; predator-prey relationship

Interspecific competition

two different species competing for the same resource

Interspecific mutualism

two different species both benefiting from each other

Interspecific parasitism

a parasite benefits and the host is harmed

Interspecific pathogenecity

a pathogen lives inside a host; causes a disease

Reasons to randomly sample

Time, destructive, feasibility

Random sampling ensures…

Representation, removal of biases, generalization

Natality (N)

the birth rate for a population

Mortality (M)

the death rate for a population

Immigration (I)

the new individuals entering a population

Emigration (E)

individuals leaving a population

Change in population size

(N+I) - (M+E)

Sigmoid Population Growth Curve

describes how a population’s size changes over time in an environment with limited resources; exponential phase → transitional phase → plateau phase

Mutualism

a close relationship between two organisms of different species, where both individuals benefit

Alien species

organisms that have been introduced to an ecosystem, and do not occur there naturally

Invasive species

alien species that cause harm to the natural ecosystem

endemic

native

How may an alien species become an invasive species?

• absence of predators in new habitat

• absence of diseases in the new habitat

• faster rate of reproduction

• larger size/more aggressive

• outcompeting for food and other resources

Competitive exclusion

states that no two species can occupy the same niche

Positive associations

occur when two species are more likely to be found together in an ecosystem. Species in mutualistic relationships have ____ associations in ecosystems.

Negative associations

occur if two species are not likely to be found together. Species competing for resources tend to have a ___ association as they avoid direct competition by being in different niches in the ecosystem.

Chi-Squared Test

used to distinguish between two distinct possibilities

Null hypothesis (H₀)

There is no significant difference between the distribution of two species; accepted if P > 5%

Alternative hypothesis (H₁)

There is a significant difference between the distribution of two species; accepted if P < 5%

Degrees of freedom

(# of rows - 1)(# of columns - 1)

Top Down Controls

pressures applied at higher trophic levels to control dynamics in an ecosystem; Predator’s control population of prey

Bottom Up Controls

resources like nutrients available to producers, affecting the growth of producers; Less producers = less resources = less population

Allelopathy

the release of chemicals by one organism which influences the germination, growth, survival, or reproduction of another organism

Root nodules in Fabaceae

____ plants develop __ that protect the bacteria from consumers; also provides carbs for the bacteria to use as an energy source; Rhizobium bacteria fix nitrogen, helping the plant avoid a nitrogen deficiency;

Nitrogen fixing

a process that converts atmospheric nitrogen gas into biologically usable ammonia

Mycorrhizae in orchids

___ provide carbs from photosynthesis for the fungus to use as an energy source; fungus absorbs and supplies nutrients from the soil that the plant needs (water, nitrogen, phosphorus)

Zooxanthellae in hard coral

___ provides a protected environment close to the surface where algae can absorb light, and also carbon dioxide from respiration; the algae provide carbs and oxygen from photosynthesis.

Ecosystem

all of the organisms and abiotic factors in an area

Open system

both matter and energy can enter and exit

Closed system

energy can enter and exit, but matter cannot

What is the primary energy source for most ecosystems?

Sunlght

Producers (autotrophs)

organism that can synthesize all of the necessary carbon compounds itself using inorganic substances in the environment

Saprotrophs

decomposers that digest things externally

Detritivores

decomposers that digest things internally

Oxidation

the loss of electrons

Reduction

the gain of electrons

Heterotroph

organisms that receive carbon compounds and energy by feeding on other organisms

digestion

chemical breakdown of molecules

Reasons for energy loss between trophic levels

Cell respiration (fewer carbon compounds available for oxidation + heat loss)
Incomplete consumption (not all matter is consumed)
Incomplete digestion (not all matter is digestible)

gross primary production (GPP)

total biomass of carbon compounds made during photosynthesis

net primary production (NPP)

the amount of biomass available to consumers due to the loss of biomass during respiration in plant cells

secondary production

increase in biomass by heterotrophs

Pool

reserve or storage place for certain elements

Flux

transfer of an element from one pool to another

Keeling curve

Photoautotrophs

use light energy to synthesize carbon compounds

Chemoautotrophs

Use the oxidation of inorganic compounds to synthesize carbon compounds

Pyramid of energy

shows the flow of energy through an ecosystem; should be drawn to scale and should be stepped, not triangular

primary productivity

producers synthesizing carbon compounds to increase their biomass

secondary productivity

heterotrophs increasing their biomass by using carbon compounds obtained through feeding

Carbon Cycle