100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Previously searched by you
Previously searched by you
logo
Population Ecology and Life History Evolution £6.49   Add to cart
Quickly navigate to
Preview
  2.  
  3. University Of Lincoln (UoL)
  4.  
  5. University Of Lincoln
  6.  
  7. Ecology (BGY1010M)

Lecture notes

Population Ecology and Life History Evolution

 5 views  0 purchase

Includes the Allee effect, intrinsic and extrinsic factors affecting population growth, life-history traits, r- and K- selected species, and reproduction-survival trade-offs.

Preview 1 out of 3  pages

Document information

  • September 15, 2021
  • 3
  • 2021/2022
  • Lecture notes
  • Jenny dunn
  • Lecture 2 of ecology

Subjects

Written for

All documents for this subject (10)

Seller

avatar-seller
chloegalvin

Content preview

Ecology
Lecture 2 Population Ecology and Life History Evolution 17/02/21

The Allee Effect
- Where the population growth rate drops at low population densities.
- Most often seen in small populations.
- Can drive species to extinction.
Population growth in real populations
- If we look at nature, we find populations tend to fluctuate.
Intrinsic factors
- Factors within the model itself such as time lags and values of r or λ – our population growth
rates.
Extrinsic factors
- Factors outside of the model, such as changes in abiotic conditions, or biotic factors such as
interactions with other species, including predators and competitors.


Monotonic damping

Damped oscillations


Stable limit cycles


Chaos




Delayed density dependence
- Delayed density dependence can cause populations to fluctuate in size.
- For example, lab populations of Daphnia show marked population cycles when in laboratory
cultures.
- As the population grew, reproduction decreased.
- But survival was less sensitive to density, and so adults continued to survive even though
resources were scarce
- As resources became more abundant, reproduction could once more take place….but the
population was made up of old, senescent individuals who laid very few eggs.
- Thus, the next up cycle of population growth was delayed, because the ↑ in fecundity at
lower density was lower than predicted (because old individuals produce few young).
Life history traits
- In many respects we have two ends of a continuum.
- The mouse can be described as an r-selected species (the r relates to the intrinsic rate of
increase – as per our last lecture).
- r-selected refers to selection for high population growth rates.
- Generally found towards the bottom of the S-shaped growth curve.

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

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

Quick and easy check-out

You can quickly pay through credit card for the summaries. There is no membership needed.

Focus on what matters

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 chloegalvin. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for £6.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

67474 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now

Start selling
£6.49
  • (0)
  Add to cart