eeb211 at Princeton University 1-3

Ecology

study of interaction between organism and between organism and their environment

what is the predominant driver of species distribution

Climate

biomes

the major life zones characterized by vegetation type

What did Alexander Von Humbolt and his ascent of Chimborazo drawing show us

that as you move up the moutatin, the temperature cools and vegation turns very quickly. There are horizontal bands of the same vegation however as you move up the mountain the type of species taht can live in certain temperatures changes. Less vegation as you move us

what are the two factors that influence biomes

mean annual precipation and mean annual temperature

Biomes are predictably found under __

particular climate regimes

_____ ranges also map onto climate

give example

individual species

ex: kangaroos are only specific subset of Aussie (where temperature and precipitation is perfect).

fundamental niche

A description of species requirement of their environment

-concept where you understand organism requirement of enviorment

-overall of all suitable variable

give an example of a one dimesntional niche axis

Organism Growth Rate

is dependent on a certain temperature and there is an optimal temperature for this organizm to maximize

One line on one axis

give an example of a two dimesntal niche

organism growth rate depends on temperature and moisture of soil

two axis- 2d

how does climate change affect chimbirazo's Andes moutains

before as you went up the moutain, temperatures got cooler and it make it unable to greener plants to survive. Due to to climate change, the entirely of the moutain has gotten hotter so species ranges are moving in altudude

How do ecologist forecast the future distribition and extinction of spcies across the globe under climate change?

Species distribition model: use the relationship between species occurences and their current climate to project their distrbution under new climate conditions

How to use the species distribution model to understand the effects of Climate change (steps) include any assumptions

1. understand what the species' climate requiremnts based on it's current distribution

2.Change the climate (predict how climate change will effect the climate)

3. Adjust the range to match the future climate (range expansion or range contraction)

*assumption: fundamental niche is fixed: not changing to climate change

what are some species distribution are limited by

competition

how can we detect if two species have overlapping niches

remove one compeititon to see if other thirve

What are the two senarioes if climate change occurs on a moutatin?

i.e. how will the plants change or not change

1. no change everything stays the same

2. low elevation plants might move up the moutain to stay within their same climate range

species geographic distribution are limited predominatly by ______ but _______ can also play a role

1. by climate

2. biotic interactions and other factors can also play a role

Predicting species distribution with climate alone

1. is or isn't

efficent but ...

is efficent

but missed the poitentially important role of chaning biotic interactions (aka new competition)

population

a group of individals of a single species living in the same general area

population growth formula

Change in number of individals from year t to T+1 (next year)= (birth-death) + (immigration -emmigration)

*can asume immigration or emigration

Density Indepedent

define Lamda

lamba= 1 + b - d

N t+1= (lamda) (Nt)

-is the multiplicative growth rate of the population over 1 year

-is lamda= 2 (pop doubled)

if Lamda= .5= pop cut in half

lambda range

0 to infinity

if >1 growth

if <1 decline

if =1 no change

ranges from 0 to infinity

CAN NOT BE negative

Contious vs Discrete Time

Cont time- Births and deaths occur continuously, such that individals at birth immediately have some chance of giving birth and dying

Discrete Time- all births and deaths occur to individals that start the time step

model of "exponential popoulation growth" in con time

rN

r= b-d

Population= (intial popl) e^(rt)

N0(e^(rt)) r= growth factor

t time

r>0 pop growth

r<0 pop shrink

r=0 pop stays the same

when are per capita births and death rate Density dependent

give an example

if they change with population density

-increasing population density may cause individals to have lower birth rates and higher death rates

why would increasing population density lower birth rate or higher death rate

within species competition

release of harmful compound

predation

disease

how can you tell when a birth or death is density dependent or density indepedent from a graph

if either is density independent- it would be a constant line

if density dependent birth rate- will be downwards sloping

if density dependent death rate- will be upwards sloping

what is the relationship between density and R

as density increase,

R decreases

when do you reach the carrying capacity

when N=K

no growth

when the graph starts to nevel off

what are x and y axis for density dependent population growth

x= number of generations

y= population size (N)

what is rMAX and what graph is it on

rMAX is the highest growth rate on a density dependent population growth

It is the first part of the density depedent population growth

what is the formula for the density depedent population growth

dN/dt= rMAX*N((k-n)/k))

n= population size

dn/dt= popoular growth rate

what formyla shoes the annual growth rate of the world population

b-d

what formula shoes the world population

n

Ecological Footprint

the amount of land required to substain an individal over their life at the standard of living for their population

Why is human carrying capacity difficuluty to caculate

1. the current population uses far more resources than needed

2. Tech improvements allowed us to use resources more efficently

3. Tech allows to power today with unstatinable resource uses (fossil fuels)

what is the most accurate way to describe population growth

simple mathmatical model

What does density depdence causes a population size to do

stabilize at carrying capacity

Why is human population growth tricky to define

we can understand it in terms of trends in birth and death rates but carrying capaity is tricky to define

when birth and death rates are density indepdent what happens

they are constant

if asked which population will growth faster when given the same intial population

ex:

pop 1:

Population size=9

Adults=7 Tadpoles 2

Population 2:

population size 9

Adults 2:

Tadpoles:7

Pop 1 because more adults to reproduct

why are diferences between individuals important for popoulation growth? (4) and what is the solution

1. only some give births (female)

2. some might be too young or too old to breed

3. some breeders will produce more young than other

4. some are so old that they are more liekly to die

sol: a model of population dynamics that incorporates the different stages of the life cycle

1. age (works for humans but not applicable for othres)

2. Stage or size (some species depend on size)

-use stage or size when...

-pop where size matters more than age

-pop where individals shrink

-pop that are dificult to age

name the three steps for a stage-based model of population

growth

For this, use example of frog popoulation with 5 total 2 adults and 3 tadpoles

1. divide the population into stages that differ in key demographic transition (birth, growth, and death rate)

- split group into one of tadpoles and one of two adults

2. Quantify the probabily of transtion between stages and the contribution of each stage to new individals

- each tadpole can either stay a tadpole, or become a frog

-each frog can be a frog or *can reproducce

3. Parameterize a matriax model of population growth

what are the four stages of a stage based moden

1. Juvenile-> Adult

-maturation (m)

2. Adult-> Juvenile

-reproduction (birth rate=b)

3.Juvenile

-survival but no maturation (Sj)

4. Adult

-adult survival (Sa)

-all of this is produced by average individal

Jt= juevilne at time T

At= Adult at Time t

Is the Stage based model discrete or cont

Discrte

what is the formula for Adults next year and Jeuvnille Next year in the stage based model

J(t+1)=(SjJt)+(BAt)

A(t+1)=(mJt)+(SaAt)

Matrix Model

Stage at Time T

J A

J (P(J->J)). (P(A->J)

A (P(J->A)) (P(A->A)

or

Stage at TIme T

J A

Stage

At J. Sj B / Jt

TIme A M Sa. / x

T+1 / At

how to multiple the matrix model

( A. B (X (Ax+By

x =

C. D) Y) Cx+dy)

*assumption A,B, C, D are constant.

What can we do ith these matrix model

Estimate Lambda, the multiplicative rate of increase

predict the stable stage distribution

examine the contribution of different life cycle transition to population growth

How do I calcuate Total population from matrix Model or Population for year 2, or year 3

Total population: Add end numbers togethers

year 2 or 3: Take T+1 and plud into new equation and use it as X and Y

stable stage distribution

the proportional distribution of individuals among stages that won't change over time

when

The ratio of Jt+1 and AT+1 levels out

how do you calcuate Lambda from Matrix Model

Take total number T+1/T. When proportion stablizes so will Lambda

elasticity

describes the proportional sensity of Lambda to small change in each matrix element

in augmenting the effective reproduction of mothers an effective way recover the population?

no