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

Gen Bio 1060 Week 15 Lecture Notes

by: Margaret Notetaker

Gen Bio 1060 Week 15 Lecture Notes Bio 1060

Marketplace > Saint Louis University > Biology > Bio 1060 > Gen Bio 1060 Week 15 Lecture 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

This is the 15 week overall, but the second week of the ecology unit (Unit 4).
General Biology II
Dr. Thole
Class Notes
25 ?




Popular in General Biology II

Popular in Biology

This 11 page Class Notes was uploaded by Margaret Notetaker on Saturday April 30, 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 12 views. For similar materials see General Biology II in Biology at Saint Louis University.


Reviews for Gen Bio 1060 Week 15 Lecture 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: 04/30/16
Margaret  S   Biology  1060  (General  Biology  II)  Week  2  Notes   Unit  4:  Ecology     4-­‐18-­‐16     Community  Ecology   • Community  ecology  refers  to  interactions  between  different  species  in  1   geographic  area   • Interactions  between  species:  symbioses   o Mutualisms:  both  species  benefit;  the  most  common  type  of  beneficial   symbioses   § Ex.  Flowers  can  only  reproduce  with  their  pollinator’s  help   o Antagonism:  one  participant  loses  more  than  it  gains   § Parasitism  (an  organism  lives  inside  of  another  and  steals  its   nutrients,  the  host  typically  becomes  ill)   § Predation  (one  organism  eats  another,  for  example  a  bird   [predator]  eats  a  fish  [prey])   § Herbivory-­‐a  form  of  predation  (animal  eating  a  plant)   § Competition  between  species  for  resources  (harmful  to  both   species)   • Niche:  a  combination    of  a  species’  physical  habitat  and  its  ecological  role  in   that  habitat   o Biotic  and  abiotic  factors  to  niches   o All  species  in  the  same  habitat  will  have  some  difference  in  niches  that   allows  them  to  avoid  some  kind  of  competition   o The  fundamental  niche:  larger  than  the  realized  niche,  consists  of  any   area  that  an  organism  could  theoretically  live   o The  realized  niche:  smaller  than  the  fundamental  niche,  consists  of   anywhere  an  organism  could  actually  live  after  taking  into  account   competition  and  biotic  factors   • Competition:  when  niches  overlap   o Intraspecific  competition:  competition  within  individuals  of  a  species   o Interspecific  competition:  two  species  competing  for  one  resource   o Interference  competition:  (still  interspecific  competition):  physical   interactions  (ex.  Fighting)  over  access  to  resources   o Exploitative  competition:  when  the  only  interaction  between  species   is  when  trying  to  use  resource   • The  more  similar  a  niche  of  2  species,  the  stronger  the  competition  (niche   overlap),  which  can  lead  to   o Competitive  exclusion:  when  competitors  cannot  coexist,  (Harry   Potter  and  Voldemort:  one  cannot  live  while  the  other  survives)  which   may  then  lead  to:   o Resource  partitioning:  subdivision  of  niche  by  organisms,  which  only   occurs  when  the  niches  don’t  overlap  completely     J.H.  Connell’s  Study  of  Barnacles   • 2  species  of  barnacle:  when  they  live  together,  one  lives  in  higher  tidal  zone   and  the  other  lives  in  a  lower  tidal  zone;  but  when  the  lower  zone  species  is   removed,  the  higher  zone  species  expands  its  niche  to  fill  both  tidal  zones     Resource  Partitioning   • Resource  partitioning  can  lead  to  character  displacement,  which  is  when  the   partitioning  is  so  extreme  that  it  leads  to  differences  in  phenotypes   o Ex.  Finches:  allopatric  (geographically  separated);  when  2  species  are   separate  (allopatric)  they  have  the  same  beak  size,  but  when  they  are   together  (sympatric)  one  species  has  a  shallower  beak  than  the  other   o Ex.  Anolis  lizards:  they  are  believed  to  have  evolved  originally  from   only  a  few  species,  but  competition  lead  to  tons  of  different  species  in   the  same  niche  (trees):  now  each  species  has  a  specific  realized  niche   in  a  non-­‐overlapping  subset  of  the  trees     Predation   • Predation  is  the  consumption  of  one  organism  (prey)  by  another  (predator),   where  prey  is  alive   o Predators/carnivores  typically  synonyms   o Grazers/herbivores  typically  synonyms   • Presence  of  predators  can  influence  competition     Parasitism   • Parasitism  is  the  ecological  interaction  in  which  one  organism  benefits  while   the  other  is  harmed   o This  is  the  most  common  feeding  mode  on  Earth   o It  can  be  viewed  as  predation   o Some  nonphotosynthetic  plants  parasitize  other  photosynthetic   plants  by  tapping  into  their  roots   o Parasitism  also  happens  a  lot  in  animals  (like  dogs  and  worms/ticks)     Mutualism   • An  ecological  interaction  in  which  both  species  benefit   • Sometimes  one  species  relies  on  the  other,  and  sometimes  both  rely  on  each   other   • Ex.  Pollination,  seed  dispersal  (seeds  and  animals  that  eat/excrete  them),   roots  and  nitrogen  fixing  bacteria,  clown  fish  and  sea  anenomes   • Facultative  Mutualism:  both  organisms  can  live  on  their  own,  they  just  prefer   to  be  near  each  other  because  they  do  well  when  they  are  together   • Obligate  Mutualism:  either  neither  or  one  of  the  species  can  live  on  their  own   o Ex.  of  obligate  mutualism:  lichen  composed  of  fungus  and  algae     Commensalism   • Commensalism  is  an  ecological  interaction  wherein  one  organism  benefits   but  the  other  has  a  neutral  experience   • Cattle  egrets  (a  type  of  bird)  live  around  cows,  and  as  cows  walk  around  and   stir  up  bugs  in  the  grass  cattle  egrets  eat  the  bugs;  the  cattle  egret  benefits,   and  the  cow  neither  benefits  nor  suffers     Mutualism  and  Coevolution   • Ex.  aphids  and  bacteria  (buchnera)  have  almost  identical  phylogenetic  trees   because  their  evolutionary  histories  have  relied  so  much  on  the  other  due  to   their  mutualistic  relationship     Summary:   o (-­‐)  means  that  the  organism  suffers  due  to  the  ecological  relationship   o (+)  means  that  the  organism  benefits  due  to  the  ecological   relationship   o (0)  means  that  the  organism  does  not  suffer  or  benefit  due  to  the   ecological  relationship   • Competition   o (-­‐/-­‐)   • Predation,  herbivory,  parasitism   o (+/-­‐)   • Mutualism   o (+/+)   • Commensalism   o (+/0)         4-­‐20-­‐16     Community  Ecology   • Keystone  species:  a  species  that  is  not  great  in  number,  but  that  is  vital  to  a   community-­‐that  community  would  change  drastically  if  the  species  were  not   there   • Communities  are  constantly  changing   o Climate   o Species  invasion   o Disturbances  (things  that  are  not  the  norm)   • Species  are  affected  by  indirect  effects  sometimes   o Ex.  if  1  prey  is  preferred,  that  has  a  positive  indirect  benefit  to  the   other  prey  in  the  area   • All  species  are  related  to  each  other  either  directly  or  indirectly   • Keystone  species  (a  second  definition):  a  species  whose  impact  on  the   community  or  ecosystem  is  disproportionately  large  relative  to  its   abundance   o Ex.  otters  eat  urchins  which  will  otherwise  overtake  giant  kelp  forests   where  other  animals  live;  without  the  otters,  urchins  take  over  and   destroy  the  kelp  and  many  other  species  will  suffer;  otters  are   keystone  species   o Ex.  beavers  construct  dams  that  make  lakes/ponds,  which  house   many  organisms;  in  this  example,  the  beavers  are  the  keystone   species   o Ex.  carnivorous  starfish  eat  mussels  that  eat  small  invertebrates;  this   allows  invertebrates  to  survive,  so  when  there  are  too  many  mussels   they  take  over  the  entire  ecosystem;  carnivorous  starfish  are  keystone   species   • Natural  disturbances   o Daily:  treefalls,  erosion,  etc.   o Seasonal:  floods,  fires,  drought,  etc.   o Multiyear:  landslides,  fires,  etc.   o Decadal:  hurricanes,  severe  drought,  etc.   o Centennial:  climate  change   • Species  richness  tends  to  be  highest  when  disturbances  are  relatively   frequent   • Succession:  a  community’s  response  to  a  disturbance   o Moving  back  into  a  destroyed  habitat  and  recolonizing   o First  organisms  to  come  in  are  lichen  and  moss,  followed  by  small   invertebrates  (r-­‐strategists),  soon  after  this  happens  the  soil  changes   from  rock  to  true  soil  due  to  plant  interaction   • Mt.  St.  Helen  eruption:  1985,  nothing  left  around  it  but  patches  of  grass;  in   2002,  trees  and  bushes  started  to  grow  back   • Primary  succession:  when  organisms  begin  colonizing  an  area  (substrate)   that  never  had  life  on  it   o Ex.  glaciers  receding   o Establishment:  Immediately  during  primary  succession,  lichen  secrete   acid  that  breaks  down  rock  and  moss  starts  to  grow  with  nitrogen   fixing  bacteria  that  prepare  the  soil  for  future  plants   o Facilitation:  alder  shrubs  start  growing   o Inhibition:  when  the  land  is  fully  colonized  and  no  other  plants  start   growing  there   • Secondary  succession:  the  existing  community  is  disturbed,  but  some   organisms  still  remain  (ex.  fire)   • Intermediate  Disturbance  Hypothesis:   o The  graph  with  disturbance  frequency  on  the  x-­‐axis  and  species   diversity  on  the  y-­‐axis  is  a  bell  curve;  a  moderate  amount  of   disturbances  is  optimal  for  biodiversity     Ecosystem  Ecology   • Ecosystem  Ecology:  Multiple  communities  of  organisms  that  live  in  an  area   and  the  chemical  and  physical  environment  that  surrounds  them   • 4  Components  of  Ecosystem  Ecology:   o Abiotic  environment   o Primary  producers   o Consumers   o Decomposers   o All  of  these  components  are  linked  by  the  movement  of  nutrients  and   the  transfer  of  energy   • Energy  FLOWS,  Nutrients  CYCLE   o The  sun  shines  on  primary  producers,  which  feed  the  consumers  and   the  decomposers,  which  feed  on  each  other,  and  all  are  influenced  by   abiotic  factors   o The  flow  of  energy  is  unidirectional  and  noncyclic;  only  the  nutrient   cycle  is  cyclic   o There  is  dissipation  of  energy  at  every  trophic  level;  but  there  is  no   dissipation  of  nutrients  at  any  level   o Energy  pools  don’t  exist  on  earth;  but  nutrient  pools  do   • Obtaining  Matter  and  Nutrients   o Producers  are  autotrophs  (typically  plants)   o Consumers  are  heterotrophs  (herbivores,  predators,  parasites)   o Decomposers  return  carbon  and  minerals  to  the  earth  (typically  fungi,   etc.)   • Energy  Flow  in  Ecosystems   o Productivity:  the  rate  of  synthesis  of  organic  matter   o Primary  productivity:  plants,  algae,  bacteria  (Trophic  Level  1)   o Secondary  productivity:  heterotroph  level,  consumers  (Trophic   Levels  2-­‐4)   § Energy  flow  is  lessened  from  one  level  transfer  to  the  next,   because  some  is  always  lost  as  heat:  only  about  10%  of   available  energy  is  converted  to  the  next  level  (energy  flow  is   inefficient)   § Ex.  1000  kg  of  grass  (primary  producers)  à  100  kg   grasshoppers  (herbivores/primary  consumers)  à  10  kg   lemmings  (predators/secondary  consumers)  à  1  kg  eagles   (predators/tertiary  consumers)   o Respiration  is  the  rate  at  which  primary  producers  break  down   organic  compounds   • Food  Webs:  the  arrows  in  food  webs  show  the  transfer  of  energy;  all  arrows   move  away  from  grass  and  upwards  towards  the  highest  level  of  consumers   o Primary  producers  get  their  energy  from  the  sun,  and  their  nutrients   from  decomposers,  which  break  down  the  dead  organisms  and  return   their  nutrients  to  the  soil/environment   • Trophic  Interactions   o Trophic  cascade:  the  effects  on  one  level  influence  the  other  levels   § Top-­‐down  effect:  when  the  effects  flow  down  through  a  trophic   chain  (issue  with  tertiary  consumer  affects  primary  producers)   • Ex.  introducing  a  new  predator   § Bottom-­‐down  effect:  when  the  effects  flow  up  through  a   trophic  chain  (issue  with  primary  producers  affects  tertiary   consumers)   • Ex.  more  primary  producers       4-­‐22-­‐16     Species  Richness  (Biodiversity)  and  Stability   • Biodiversity  is  influenced  by:   o Primary  productivity  (sunlight  and  primary  producers)   o Habitat  heterogeneity  (the  more  organisms  are  able  to  live  in  a   habitat,  the  more  diversity  in  species)   § Habitat  heterogeneity  is  the  ability  of  a  habitat  to   accommodate  more  species   o Climatic  factors   § More  species  might  be  expected  to  coexist  in  a  seasonal   environment   • Species  rich/biodiverse  ecosystems  do  better  at  resisting  compositional   changes  in  habitat   • Diversity  stability  hypothesis:  preexisting  stability  between  species  in  an   environment  causes  difficulty  for  foreign  species  to  move  in  because  there  is   already  a  very  stable  biomass  (number  of  organisms  in  balance)   o More  species  in  a  habitat  causes  less  year-­‐to-­‐year  variation  in  biomass   o If  there  is  a  drought,  the  resulting  biomass  decrease  is  negatively   related  to  species  richness     Ecosystem  Dynamics:  An  Example   • Primary  Producers  (can  only  be  photosynthetic  organisms)   o Grass   • Primary  Consumers   o Bison   o Grasshoppers   • Secondary  Consumers   o Squirrels   o Cattle  Egrets   o Prairie  Dogs   • Tertiary  Consumers   o Owls   • Herbivory:  Grasshoppers  (+)/Grass  (-­‐)  ;  Bison  (+)/Grass(-­‐)   • Commensalism:  Cattle  Egrets  (+)/Cattle  (0)   • Competition:  Bison  (-­‐)/Grasshopper  (-­‐)  ;  Squirrels  (-­‐)/Prairie  Dogs  (-­‐)   • Food  Web:   Owl     Tertiary  Consumers   Prairie  Dog   Squirrel   Cattle  Egret     Secondary  Consumers     Grasshopper       Bison     Primary  Consumers         Grass         Primary  Producers     Decomposers   Nutrients  in  soil   A  set  of  arrows  points  from  all   organisms  to  these  2  things;  all  other  arrows  point  from  each  organism  to  the   next  row  up     Biomes:  Climate  and  Habitat  are  Viewed  as  the  Same  Thing   • Seasons  are  due  to  a  tilt  in  earth’s  axis;  the  equator  is  always  hotter  because   of  concentrated  sunrays   • Earth’s  air  circulates;  the  equator  has  warm  air,  and  as  warm  air  rises,  it   dumps  its  water  (causing  rainforests)   o Every  30  degrees  of  latitude  (up  and  down),  water  goes  back  into  the   atmosphere  (deserts  are  found  around  these  areas)   • The  Rain  Shadow  Effect:   o Winds  have  to  rise  over  mountains,  and  as  they  rise  they  cool,  which   causes  them  to  dump  rain  wherever  the  air  starts  to  get  cooler  (the   side  of  the  mountain  away  from  the  wind  is  dry,  while  the  side  by  the   wind  is  rainy)   o The  rain  shadow  itself  is  the  dry  side  of  the  mountain   • Evapo-­‐Transpiration  Ratio   o This  is  the  ratio  of  evaporation  to  transpiration   o Deserts:  low  precipitation,  rapid  evaporation;  plants  reduce   transpiration  (high  rate)   o Rainforests:  high  precipitation,  high  evaporation  and  transpiration   (low  ratio)   • Terrestrial  Biomes  reflect  the  distribution  of  climate  and  topography   o Elevation  and  latitude  determine  rainfall   • Terrestrial  Biomes:   o Desert:  little  rain  and  resources   o Tropical  Rainforest:  high  temperature,  precipitation,  and  diversity   o Savanna:  tropical  grasslands  with  seasonal  rain   o Chaparral:  shrubs,  small  trees,  adapted  to  withstand  fire   o Temperate  Grassland:  rich  soil  between  equator  and  poles   o Temperate  Deciduous  Forests:  mild  seasonal  climate,  plentiful  rains   o Temperate  Coniferous  Forests:  along  coastlines  in  temperature   climates   o Taiga:  northern  forest  where  winters  are  harsh   o Alpine:  similar  to  tundra,  but  no  permafrost  below  soil   o Tundra:  mostly  frozen,  treeless,  short  growing  season,  permafrost     Temperature  and  Precipitation  Determine  Biomes  and  Primary  Productivity  Levels   o Productivity  and  precipitation  as  well  as  productivity  and  temperature  are   both  generally  directly  related   o Tropical  rainforests,  therefore,  have  the  highest  productivity   o There  is  way  more  water  on  earth  than  land   o Aquatic  Biomes:   o Freshwater:  lakes  and  ponds,  rivers  and  streams   o Saltwater:  open  ocean,  estuaries  and  wetlands   o Photic  zone  in  open  ocean  is  only  zone  that  can  contribute  to  primary   productivity  (upper  200  m)     Review  Questions   1. Resource  partitioning  in  Anolis  lizards  is  an  example  of   a. Intraspecific  competition   b. Interspecific  competition   c. Interference   d. Exploitative  competition   2. Resource  partitioning  reults  in:   a. Individuals  of  each  species  sharing  resources  they  both  use   b. Individuals  of  each  species  hybridizing  in  regions  of  overlap   c. Movement  from  fundamental  niche  to  realized  niche  for  both  species   d. Movement  from  realized  niche  to  fundamental  niche  for  both  species   3. Which  best  describes  the  kind  of  resources  individuals  compete  for?   a. Food/nutrients   b. Space/shelter   c. Mate  access   d. Can  be  any  resource  that  is  limited  in  an  environment   4. Cows  have  bacteria  in  their  rumen  that  can  digest  cellulose.  What  is  the   relationship  between  the  cow  and  the  bacteria?   a. Parasitism   b. Commensalism   c. Predation   d. Mutualism   e. Antagonism   5. When  humans  are  born  their  guts  are  first  colonized  by  bacteria  that  are  able   to  live  independently;  but  eventually  these  bacteria  are  replaced  by  bacterial   species  that  can  only  survive  inside  the  human  gut.  Which  of  the  following  is   true?   a. This  is  a  commensalistic  relationship  that  begins  with  facultative   species  and  ends  with  obligate  species   b. This  is  a  parasitic  relationship  that  begins  with  obligate  species  and   ends  with  facultative  species.     c. This  is  a  mutualistic  relationship  that  begins  with  facultative  species   and  ends  with  obligate  species.   d. This  is  an  antagonistic  relationship  that  begins  with  facultative   species  and  ends  with  obligate  species.   6. The  volcanic  oceanic  island  of  Krakatoa  is  located  in  Indonesia.  In  1883,  this   island  experienced  a  massive  volcanic  explosion  that  killed  most  of  the  plants   and  animals  living  on  the  island.  After  a  very,  very  long  time  period  of   recovery  from  the  eruption,  which  group  of  organisms  would  we  expect  to   have  the  most  representation  among  native  species  on  the  island?   a. Lizards   b. Small  mammals   c. Birds   d. Beetles   7. In  this  food  web,  which  of   the  following  describes  the  minnow  fry?   a. Primary  producer   b. Primary  consumer   c. Secondary  consumer   d. Tertiary  consumer   8. In  general,  a  larger  biomass  in  primary  producers  for  a  trophic  pyramid:   a. can  support  more  biomass  at  higher  trophic  levels  because  more   energy  is  available  between  the  level  of  primary  producer  and   primary  consumer.   b. does  not  affect  the  amount  of  biomass  that  can  be  supported  at  the   level  of  primary  producer.   c. can  support  less  biomass  at  higher  levels  because  more  energy  is  lost   between  the  level  of  primary  producer  and  primary  consumer.   9.  Which  one  of  the  following  statements  about  the  trophic  cascade  in  the  sea   otter  and  sea  urchin-­‐kelp  communities  along  the  West  Coast  of  North   America  is  FALSE?   a. Increased  sea  otter  populations  are  linked  to  reduced  sea  urchin   populations   b. Increased  orca  (killer  whale)  predation  on  sea  otters  is  linked  to  more   profuse  growth  of  kelp  forest.   c. Increased  sea  otter  populations  are  linked  to  more  profuse  growth  of   kelp  forests.   d. Increased  orca  (killer  whale)  predation  on  sea  otters  is  linked  to   increased  sea  urchin  populations.   10.  Pertaining  to  the  example  food  web:  In  a  drought  year,  there  is  much  less   grass  biomass  produced.      What  would  you  expect  to  happen  to  the  number   of  owls?   a. Increase   b. Decrease   c. Stay  the  same   11.Pertaining  to  the  example  food  web:  In  a  drought  year,  there  is  much  less   grass  biomass  produced,  leading  to  a  decrease  in  the  number  of  owls.      This  is   an  example  of:   a. Top-­‐down  effect   b. Bottom-­‐up  effect   c. Diversity  stability  hypothesis     Answers:   1. B.  interspecific  competition   2. C.  movement  from  the  fundamental  niche  to  the  realized  niche  for  both   species   3. D.  can  be  any  resource  limited  in  an  environment   4. D.  mutualism   5. C.  mutualistic,  facultativeàobligative   6. D.  beetles   7. C.  secondary  consumer   8. A.  more  biomass  at  higher  temperatures   9. B   10.B.  decrease   11.B.  bottom-­‐up  effect  


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

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

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."

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

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.