MARB 425 Exam 1

ecology is a mix of _______ and _______ factors

abiotic; biotic

abiotic factors

temperature, salinity, sunlight

biotic factors

animals and plants

population factors

birth rates, death rates, immigration, emigration

ecology is the change in…

population size and biomass

population ecology is understanding the…

fluctuations of population

natural selection

end result of ecology in action

ecological interaction leads to…

evolutionary change (population change over time)

ecologists want to identify…

why abiotic and biotic factors influence population change

functional levels in ecology

• individual

• population

• community

• ecosystem

• landscape/region

• biosphere

population

group of same species occupying a particular region at a given time interbreeding

community

all populations in a given time and area

ecosystem

community and abiotic factors

landscape/region

all ecosystems

biosphere

global sum of all ecosystems

individual level patterns

individual growth rate, reproduction, survival, and movement

population level patterns

intraspecific competition, population size/age structure, population growth and mortality rate, and spatial/temporal distribution

community level patterns

interspecific competition, predation, diversity, zonation, and succession

ecosystem level pattern

system biomass/productivity, resilience/stability, and nutrient cycling

unitary organism in populations

population assessments based on number (density)

modular organism in populations

difficult to count; population assessments based on percent over and biomass

pattern of random spatial structure of populations

equal probability of occurring anywhere

process of random spatial structure of populations

neutral interactions

pattern of random spatial structures are…

rare

pattern of regular/even spatial structure of populations

uniformly spaced through environment

process of regular/even spatial structure of populations

antagonistic interactions

pattern of clumped/patchy spatial structure of populations

in areas of high local abundance, separated by areas of low abundance

process of clumped/patchy spatial structure of populations

attraction of individuals or to a resource

pattern of clumped/patchy spatial structures are…

most common

the size of the scale of distributions affects the…

spatial structure

populations change due to…

immigration and emigration

single population

populations are rarely continuous but exist as separate or spatially disjunct units (local or sub populations) distributed in patches. If close enough that individuals move freely among patches.

metapopulation

if patches are not close enough and species exist as distinct, partially isolated local populations may each possess their own population dynamics

assumptions of metapopulations

1. limited dispersal/connectivity

2. subpopulations with independent birth and death rates

remember single population

all local populations respond in the same manner with net gain or loss in all local populations

if local populations are in fact one metapopulation, …

some show net gain and some some net loss in ecological time

metacommunity

set of interacting communities that are linked by dispersal/immigration/emigration of multiple potentially interacting species

density

number of organisms per unit area or volume

two approaches to estimate population density

1. absolute density

2. relative measures of abundance

relative measures of abundance

distribution of individuals among species in a community

How to measure relative of abundance

1. sample entire population total counts

2. sample part of population (extrapolate density)

methods of measuring relative of abundance

quadrats, net gears, visual surveys, and mark-capture

quadrats

sampling of any shape

net gears

active sampling

passive sampling

gear that collects organisms over time

active sampling

gear that is actively collecting organisms

visual surveys

approach similar to net gears with defined area/volume sampled

mark-recapture

indirect method based on premise that proportion of marked animals recaptured representative of proportion marked in entire population

mark-recapture is used to estimate…

population density, birth and death rates, movement, and range

mark-recapture technique

1. capture

2. mark

3. release

4. recapture

mark recapture equation (solving for total population size)

2nd sample marked animals/ 2nd sample total caught = 1st sample marked animals / total population size

measuring relative abundance rather than density using…

• traps

• longlines, gill nets, and drift nets

• visual surveys

• active acoustics

• passive acoustics

• indicators of presence

traps are…

passive gear

units for relative abundance

CPUE (catch per unit effort)

example of CPUE

individuals/hour

longlines, gill nets, and drift nets are…

passive gear

problem with passive gear

bycatch

caveat of estimating abundance with passive gear/CPUE

visibility of the water can impact catchability in gill nets

ranking visual surveys methods

• roving driver technique

• rapid visual count or technique (RVC/RVT)

roving driver technique

divers swim freely at site and record every observed species that can be positively identified

rapid visual count or technique

diver observes species at specific time intervals and scores points at each interval

active acoustics

biomass or summation of echoes proportional to density

echo sounder uses…

echo strength which can differ density from H2O to find fish targets

sound generated ________ by __________

actively; transducers

imaging sonars

transmit sound pulses and convert the returning echoes into digital images

imaging sonar advantage

works in zero visibility conditions

acoustic shadows are used for…

ID

passive acoustics

vocalization

vocalization

number of calls proportional to the number of animals

natural indicators of presence

counting something left by the individuals instead of the individual itself

natural indicators of presence example

• bitemarks on corals left by fish

• count number of cuttlebones on beaches per hour

life table

age-specific summary of the mortality rates operating on a cohort of individuals

x of life table

age

nx of life table

number alive at age x

lx of life table

proportion of organisms surviving at the start of age x

dx of life cycle

number dying between age interval x to x+1

qx of life cycle

per capita rate of mortality during age interval x to x+1

lx=

nx/n0

dx=

nx-nx+1

qx=

dx/nx

type 1 survivorship curve

most individuals die late in life

type 2 survivorship curve

uniform rate of decline

type 3 survivorship curve

huge decline in young

type 1 survivorship curve examples

cetaceans and manatees

type 2 survivorship curve examples

shorebirds and reptiles

type 3 survivorship curve examples

crustaceans, fish, and octopus

survivorship curve is determined by…

number of offspring

the more offspring…

the lower the survivorship curve

population capacity for growth is determined by…

combined lx and mx that leads to population change

mx

number of offspring produced

rate of increase (positive or negative) in response to changes like…

age distribution, social structure, genetics, and environment

organisms innate capacity for increase

fertility/fecundity, longevity, and speed of development (TG)

B-D=poisitive

increase of population

B-D=negative

decrease of population

net reproductive rate

R0

net reproductive rate equation

R0=number of daughters born generation t+1 / number of daughters born generation t

R0=

Σlx*mx

R0=1

stable population

population growth varies as a function of…

1. age distribution

2. age-specific rates

3. age-survival rates

population increase described by…

dN/dt=(b-d)N