Summary
Summary IEB Life Sciences Environmental Studies Notes 2022/2023
- Course
- Institution
In depth summary of everything you need to know for matric population ecology
[Show more]
Seller
Follow
chabukambafwile
Content preview
POPULATION ECOLOGYA population is a group of organisms of the same species inhabiting a defined
area so close to each other that random interbreeding takes place
POPULATION SIZE
Population parameters are the only factors that can affect a populationsize
Birth rate increases the no of indiv in a set time births toooyear
it indec finite
Mortality decreases the no of indiv in a set time deaths noooyear
Immigration increases the population size due to migration into the area from elsewhere
Emigration decreases the population size due to migration out of the area to elsewhere
increasing population the growth decreasing population ve growth
open population is when all 4 population parameters can happen
closed population is when certain population parameters such as im and emigration
cannot happen
GROWTH CURVES
GEOMETRIC EXPONENTIAL GROWTH
growsmore quickly because there are more
individuals to reproduce
THELAGPHASE slow increase in the beginning because
time there are less individuals to reproduce
These develop into logistic growth curves
graphs usually
Limiting factors are anything that tends to slowdown increasinggrowthThese can be
Density dependant factors or density independent factors
lack offoodwater space natural disasters
predation incolonisation
disease abiotic factors
parasitism
, LOGISTIC GROWTH CURVE negative feedback
environmental resistance
f
phase
É growthphase capacity equilibrium
i date destruction
time
Environmental resistance is the effect of limiting factors It is directly proportional
to the population growth If not quick strong enough the death phase occurs
Equilibrium phase is a level where the environmental resistance stopping thegrowth
is equal to the reproductive pressure causing population growth
carrying capacity is the population size where reproductive pressure and
environmental resistance balance exactly consistant population size
MEASURING POPULATION SIZE
Dependant on area size and species
DENSITY of a population is measured as thenumber of individuals
per unit area
DIRECT TECHNIQUES
A census is where every individual in thespecies is counted When this is not possible
a sample can be used and then multiplied for an estimation
INDIRECT TECHNIQUES
Average no of sampled plantsquad totalnumber of sampled plants
number of quadrats
population size Average no of sampled plantsquad x total area
g g g
MARK RECAPTURE METHOD
total population marked indiv of population x totalsample size PetersenIndex Formula
marked indiv of sample
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller chabukambafwile. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.76. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
73091 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now