New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Biology 1060 Unit 4 Week 1 Notes

by: Margaret Notetaker

Biology 1060 Unit 4 Week 1 Notes Bio 1060

Marketplace > Saint Louis University > Biology > Bio 1060 > Biology 1060 Unit 4 Week 1 Notes
Margaret Notetaker

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

These are the first week of lecture notes for Unit 4 of General Biology II, which is Ecology.
General Biology II
Dr. Thole
Class Notes
Ecology, Biology
25 ?




Popular in General Biology II

Popular in Biology

This 7 page Class Notes was uploaded by Margaret Notetaker on Monday April 18, 2016. The Class Notes belongs to Bio 1060 at Saint Louis University taught by Dr. Thole in Spring 2016. Since its upload, it has received 11 views. For similar materials see General Biology II in Biology at Saint Louis University.


Reviews for Biology 1060 Unit 4 Week 1 Notes


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 04/18/16
Margaret  S   Biology  1060  (General  Biology  II)  Week  14  Lecture  Notes   Unit  4:  Ecology     4-­‐11-­‐16     What  is  Ecology?   • The  relationship  between  organisms  and  their  environment  (between   individual  organisms,  and  between  multiple  organisms  and  the  environment)   o Ex.  A  bird  building  a  nest  in  a  tree:  relationship  between  bird  and  tree   is  ecology   o Ex.  Our  bodies  are  ecosystems  for  other  organisms:  the  interaction   between  microbes  and  us  is  ecology   • Limits  to  populations:  Population  ecology   o Thomas  Malthus,  1790:  1  census  of  U.S.,  population  had  doubled  in   25  years  which  wouldn’t  work  in  Britain  (Britain’s  population  couldn’t   conceivably  double  in  25  years);  this  only  works  in  the  U.S.  because  at   that  time  there  was  a  lot  of  uncolonized  space  (once  we  murdered  all   the  Native  Americans  because  we  were  horrible)   o This  study  influenced  Darwin:  lead  him  to  believe  resources  are   limited  for  all  species,  which  is  when  natural  selection  kicks  in  (the   most  adapted  individuals  live,  the  least  adapted  individuals  die)   o Populations  are  the  fundamental  units  of  evolution   § Populations  evolve;  not  individuals     Population  Ecology   • Population  ecology  is  the  study  of  how  and  why  a  population  changes  over   time   • Populations  are  described  by  3  key  factors:   o Size   o Geographic  range   o Spatial  distribution  (density):  it  can  be  equal  within  the  range  or   clustered  in  certain  areas   • To  measure  the  size  of  a  population:   o Census:  count  everyone;  organisms  must  be  easy  to  observe,  not  too   numerous,  and  live  in  an  easily  defined  area   o Sampling:  sessile  (stationary)  organisms;  count  how  many  are  in  a   square  foot,  then  multiply  by  the  number  of  square  feet  in  the  area  the   population  lives  (often  done  with  plants)   o Mobile  organisms:  mark-­‐and-­‐recapture  (collect  a  certain  number  of   organisms,  label  them,  and  recapture  the  same  number  later  on  to  see   how  many  are  new  and  how  many  are  recaptured)   • The  specific  math  behind  these  methods  is  not  important  for  the  test     Population  Ecology  Behind  Krill   • The  estimated  population  is  800  trillion   • They  live  off  the  coast  of  Antarctica   • The  population  density  diagram  shows  an  unequal  density,  and  the  average   is  42  million  krill  per  kilometer  squared   • These  statistics  will  likely  change  because  that  is  the  nature  of  population   statistics   o Ex.  An  increase  in  the  number  of  predators  will  cause  population  size   to  decrease,  then  the  predator  population  size  will  decrease  after  the   krill  decrease  in  number   o Ex.  Krill  need  cold  water  to  live  in,  but  if  water  warms  (climate   change)  the  population  size  may  decrease     Spatial  Distribution   • Random:  no  pattern  to  dispersal  of  individuals   • Clustered:  clumped  areas  of  organisms  with  empty  spaces  in  between   o Ex.  Could  be  clustered  because  of  clustered  resources   • Dispersed  (regular):  equal  space  between  individual  organisms   o This  happens  with  territorial  animals   o This  also  happens  with  plants  that  release  chemicals  that  prevent   growth  of  anything  else  nearby   • Could  start  with  1  distribution  type,  then  change  over  time   o Ex.  Shrubs  may  grow  together  in  their  youth  in  clumps  for  survival;   start  being  more  random  when  competition  starts;  and  end  up  equally   spaced  by  maturity     Population  Dynamics   • Birth  rate  (positive  contributor  to  population  size)  vs.  Death  rate  (mortality   rate:  negative  contributor  to  population  size)   • Immigration  rate  (positive;  individuals  coming  into  population)  vs.   Emigration  rate  (negative;  individuals  leaving  population)   • We  can  predict  population  growth  over  time  using  mathematical  models   o Imagine  bacteria  on  a  petri  dish  (no  immigration/emigration)   o T1-­‐T0  =  ΔT  (T=time,  N=  population  size)   o Graph:  (T0,  N)  (T1,  N1)  (T2,  N2)   o All  time  intervals  are  equal   o Change  in  population  size  from  T0  to  T1:  N1-­‐N  =  ΔN   o Growth  rate  from  T0  to  T1:                              N1  –  N      =  ΔN                          T1  –  T0          ΔT   • Per  capita  growth  rate  T0  to  T1  (takes  into  account  starting  population  size):   o (ΔN/ΔT)/N,    where  N  =  initial  population  size   • Modeling  population  growth:   o T0  =  10   o 1  hour  later  (T1)  =  20   o Per  capita  growth  rate?  (r?)   o (ΔN/ΔT)/N  =  ((20-­‐10)/1)/10  =  1   • Modeling  bacterial  growth   o N  =  10,  r  =  1   o Nt  =  N1(1+r)^T   o What  will  the  population  size  be  at…   § T  +  1?      10  x  2  =  20   § T  +  2?     20  x  2  =  40   § T  +  3?      40  x  2  =  80   § T  +  4?      80  x  2  =  160   § T  +  5?      160  x  2  =  320   § T  +  6?      320  x  2  =  640   o Exponential  growth  curve:  the  per  capita  growth  rate  (r)  is  constant   o     Population  Growth   • Population  growth:  ΔN  =  (b-­‐d)  +  (i  –  e)   o b  =  births   o d  =  deaths   o i  =  immigration   o e  =  emigration   • Per  capita  growth  rate:  r  =  (ΔN/ΔT)/N   • When  unlimited  growth  is  allowed,  the  growth  curve  will  be  exponential   • Exponential  growth  is  independent  of  population  size   • The  population  with  the  highest  growth  rate  has  the  curve  that  increases  the   fastest   • Exponential  growth  of  conifer  (Scots  pine):  pollen  accumulation  rate  in  lake   sediments  from  different  time  points  are  sampled  to  measure  population   growth   • Assumptions  of  exponential  growth:   o r  is  constant  over  time,  no  immigration  or  emigration,  resources  are   unlimited   o Because  of  these  assumptions,  exponential  growth  is  not  realistic;   populations  will  eventually  reach  carrying  capacity  (K)  because   resources  are  not  ever  unlimited       4-­‐13-­‐15     Factors  that  Cause  Mortality  Differ  Throughout  the  Life  Cycle   • Survivorship  curves  plot  the  proportion  of  the  cohort  alive  at  the  end  of  each   stage     3  Major  Types  of  Survivorship  Curves   • Type  1:  (humans):  survivorship  curve  is  really  high,  most  individuals   approach  the  maximum  life  span   • Type  2:  (songbirds):  constant  survivorship,  an  individual  is  not  particularly   more  likely  to  die  earlier/later  in  life   • Type  3:  (plants):  death  rate  is  high  at  the  start  of  life,  survivorship  is  high   later  in  life     Life  History  Strategies   • BirthàGrowthàReproduceàDeath   • Tradeoff  between  reproduction  and  lifespan,  and  number  of  offspring  and   investment  per  offspring   o r-­‐selected  species  maximize  their  reproductive  role;  they  produce   many  offspring  and  don’t  invest  much  in  them   o K-­‐selected  species  live  at  their  carrying  capacity  of  environment;  they   produce  fewer  offspring  but  invest  in  them  more       4-­‐15-­‐16     r-­‐Strategists  and  K-­‐Strategists   • r-­‐Strategists  have  lots  of  offspring,  with  low  survival  (ex.  Mosquitos  and  most   insects)   • K-­‐Strategists  have  few  offspring  with  high  survival  (ex.  Elephants)   • K-­‐selected  strategists  stay  around  carrying  capacity  (they  thrive  at  K,  a  value   of  population  size  that  is  sustainable  in  their  environment)   • r-­‐selected  strategists  fluctuate  a  lot  more,  they  just  maximize  r   • Oak  trees  are  K-­‐selected  because  their  acorns  are  large  and  survive  longer   • Giant  clams  are  r-­‐selected     Metapopulation   • A  metapopulation  is  a  group  of  populations  linked  by  migration   • They  are  dynamic;  they  undergo  a  lot  of  extinction  and  recolonization  but  the   extinction  is  local  (one  group  becomes  extinct,  so  its  easy  for  another  group   to  recolonize  the  same  area)   • They  can  be  naturally  occurring  or  artificial  (we  create  metapopulations   when  we  destroy  large  habitats)   • When  the  species  are  isolated  into  patches,  they  will  have  more  species  going   extinct;  but  when  “corridors”  connect  the  patches  of  habitat,  less  species  go   extinct  than  in  the  isolated  patches,  though  there  will  still  not  be  as  many   populations  as  in  the  original  large  group   • Wildlife  overpasses  on  roads  provide  corridors  in  forests,  etc.       Review  Questions  will  be  posted  this  weekend  (4-­‐22)  


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Jennifer McGill UCSF Med School

"Selling my MCAT study guides and notes has been a great source of side revenue while I'm in school. Some months I'm making over $500! Plus, it makes me happy knowing that I'm helping future med students with their MCAT."

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.