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Name:  __________________________________________    Class:  ________________________________  

Biology  Weekly  Packet    March  25th  –  March  28th,  2013  

Monday  March  25,  2013  Energy  Flow  In  Ecosystems  

Food  chain/food  web:      shows  the  flow  of  energy  from:  autotrophsàherbivoresà  carnivores  

 Ecosystem  Interdependence-­‐  even  a  small  change  in  the  natural  relationships  can  have  a  big  impact  on  an  ecosystem.    When  you  look  at  a  food  web,  the  change  in  one  group  will  affect  all  of  the  groups  connected  to  it  the  most,  but  there  will  be  an  impact  on  every  level  in  some  way.    Every  step  in  the  food  web,  energy  pyramid  or  biomass  pyramid  represents  a  trophic  level.  Trophic  levels  show  many  times  energy  has  been  transferred  (like  a  trophy!)    Energy  pyramid:  shows  energy  in  each  trophic  level.  Only  10%  of  the  energy  is  transferred  to  the  next  trophic  level  (so  you  start  with  100%  in  producers,  then  10%  in  herbivores,  then  1%  in  carnivores.    This  helps  explain  why  there  are  less  carnivores  than  herbivores).  

               Biomass:  the  amount  of  dry  organic  material  an  organism  has  Biomass  pyramid:  shows  the  amount  of  organic  (living)  material  in  a  given  trophic  level.    Producers  usually  have  the  greatest  biomass  and  the  most  energy.    The  higher  you  go  in  both  pyramids,  the  less  energy  and  less  biomass  is  present.    Ultimately,  all  organisms  rely  on  the  sun  for  their  energy!    

                                                                                                                                                   

Monday  Catalyst  

 

 

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 Tuesday  March  26,  2013  

Types  of  Growth  Natural  Population  Growth:  s  shaped  curve.    The  rate  of  population  growth  starts  off  fast  and  then  growth  slows  when  the  environment  reaches  the  carrying  capacity  (the  largest  number  of  organisms  of  a  species  that  can  be  supported  by  the  environment).    Limiting  factors:  limit  how  large  a  population  can  grow.    Examples  include  water,  food,  space,  minerals  like  salt    Unrestricted  population  growth  (invasive  Species  growth)-­‐non  native  species  is  introduced;  few  natural  predators,  large  food  supply.    Just  keeps  going  up  and  up  because  there  is  nothing  to  limit  the  growth.    Predators  are  necessary  to  help  to  maintain  a  normal  population  size.    When  populations  of  prey  get  too  large,  predators  can  eat  the  extra  organisms  and  bring  the  population  size  down.    When  populations  of  prey  get  too  low,  then  some  predators  will  die  of  starvation  and  let  the  prey  population  grow.    Without  the  predators,  the  population  will  keep  growing  uncontrollably  until  it  uses  up  all  of  a  limiting  factor  and  then  crashes  (goes  down  quickly  or  possibly  goes  extinct)  when  it  runs  out  of  something.    In  sum,  predators  help  to  maintain  a  balanced  population  size.  Tuesday  Catalyst  

 

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 Wednesday  March  27,  2013  

Biogeochemical  Cycles  Biogeochemical  Cycles-­‐cycles  of  elements  or  compounds  that  involve  living  and  non-­‐living  components    Nitrogen  Cycle:    78%  of  the  Earth’s  atmosphere  is  Nitrogen  (not  many  organisms  can  use  it)  Nitrogen  Fixation:  bacteria  trap  N2  and  form  NH3  (ammonia)  Nitrification:  other  bacteria  change  the  ammonia  into  Nitrates  (NO3)  and  Nitrites  (NO2)  

-­‐Plants  can  use  Nitrates  and  Nitrites  to  make  proteins,  animals  eat  these  proteins  and  release  them  back  into  the  Earth  as  waste  (fertilizers).  

-­‐When  animals  die  they  are  broken  down  by  decomposers  which  put  nitrogen  back  into  the  soil.  Denitrification:  bacteria  change  the  nitrates  back  into  nitrogen  gas  (N2)  and  release  it  into  the  atmosphere.                                                                                                            N2                                            NO2  and  NO3                                                                                                                                    NH3  (ammonia)    Water  Cycle:       Precipitation-­‐water  moves  from  the  atmosphere  to  the  ground  (rain,  snow,  sleet)     Evaporation-­‐  water  becomes  water  vapor  back  in  the  atmosphere     Transpiration-­‐  plants  put  water  back  in  the  atmosphere    Carbon  Cycle:  Plants  use  Carbon  Dioxide  (CO2)  from  the  atmosphere  to  form  organic  molecules  (glucose)  Animals  eat  these  organic  molecules  (glucose)  and  release  C02  back  into  the  atmosphere  through  respiration.    When  the  animals  die,  the  decomposers  release  CO2  back  in  the  air  and  some  of  the  carbon  is  trapped  in  the  ground  where  it  will  become  fossil  fuels  (coal,  oil).    Burning  fossil  fuels  or  organic  matter  releases  more  CO2  in  the  atmosphere.  

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Nitrification  Fixation  

Nitrogen  Fixation  Denitrification  

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 Oxygen  Cycle:    Photosynthesis-­‐water  molecules  are  split  into  hydrogen  and  oxygen.  The  oxygen  is  released  into  the  air.  Cellular  Respiration-­‐animals  use  oxygen  in  respiration  and  release  CO2.  Most  of  the  Earth’s  oxygen  is  found  in  the  Earth’s  crust  and  is  not  usable.  Some  of  the  oxygen  is  found  in  the  ozone  which  shields  the  Earth  from  harmful  Ultraviolet  rays          Wednesday  Catalyst  

 

 Thursday  March  28,  2013  

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Respiration  Photosynthesis  

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Thursday  Catalyst  

 

   Weekly  Vocabulary  Carrying  Capacity-­‐  the  maximum  number  of  organisms  that  an  environment  can  support  Commensalism-­‐  an  interaction  where  one  organisms  benefits  and  the  other  is  not  effected  Interdependent-­‐  when  two  things  are  connected  and  changing  one  will  affect  the  other  Mutualism-­‐  an  interaction  where  both  organisms  benefit  Parasitism-­‐  an  interaction  where  one  organism  benefits  and  the  other  suffers  Symbiosis-­‐  an  interaction  where  two  organism  rely  or  need  each  other  to  survive    Weekly  Objectives  Monday:  SWBAT  use  a  food  web  to  determine  the  effects  of  changing  an  ecosystem  and  interpret  an  energy  pyramid.  Tuesday:  SWBAT  describe  the  levels  of  ecological  organization  and  the  types  of  growth.  Wednesday:  SWBAT  summarize  the  important  components  of  the  resource  cycles.  Thursday:  Quiz  

 Homework  Monday  March  25,  2013  Which  organism  is  the  producer?    What  organisms  eat  penguins  (2)?      What  organisms  does  the  killer  whale  eat  (4)?      

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What  would  happen  to  the  leopard  seal  if  the  cod  population  died  out?  WHY?  (Hint:  would  it  increase  or  decrease?)          What  would  the  killer  whales  do  if  the  elephant  seals  died?    Why?  (Hint  what  else  would    they  eat?)      If  the  krill  population  decreased,  what  would  happen  to  the  penguin  population?    Why?        Which  organisms  are  the  top  consumers  (3)?  

 What  is  the  producer?    

 What  are  the  primary  consumers?    Another  bird  population,  which  foxes  can  eat,  enters  this  food  web.    What  would  happen  to  the  fox  population?  WHY?            What  would  happen  to  the  populations  of  the  herbivorous  insects  and  the  predaceous  insects  if  the  spiders  were  eliminated  by  insecticide?  WHY  ?      What  would  happen  to  the  snake  population  if  the  toads  went  extinct?    What  would  the  snakes  try  to  do  to  survive?      Directions:  Using  the  food  web  to  the  left,  put  the  hawk,  snake,  shrew,  frog,  marsh  grass,  grasshopper,  cricket,  and  cattail  into  the  food  pyramid  to  the  right.      

                     

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1.  Name  the  two  primary  consumers:    2.  Which  trophic  level  has  the  greatest  total  amount  of  energy  to  transfer  to  the  next  tropic  level?      3.  Which  trophic  level  has  the  least  amount  of  energy  ?    4.  What  happens  as  the  amount  of  energy  in  the  pyramid  as  it  moves  up  through  different  levels?      5.  If  there  were  5,000  Kcal  of  energy  in  the  marsh  grass,  how  much  energy  would  make  it  to  the  snake?      6.    If  there  were  40,000  g  of  biomass  in  the  grasshoppers,  how  much  biomass  would  make  it  to  the  hawk?  

   7.    If  the  snake  received  50  Kcal  of  energy,  how  much  energy  was  in  the  cattails?      8.    If  the  shrew  has  500g  of  biomass,  how  much  was  in  the  marsh  grass?    How  much  would  make  it  to  the  hawk?      9.    If  the  shrew  population  declined,  what  would  happen  to  the  frog  population?    Why?  

 Homework  Tuesday  March  26,  2013  Draw  the  graphs  of  the  deer  populations  from  the  first  game  (without  a  predator)  and  the  second  game  (with  a  predator):                                                      Game  One  (no  predators)                                                                                                                                Game  Two  (with  predators)                        

Population  Size  

(Deer)  

Population  Size  

(Deer)  

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                                   Time  (rounds  of  the  game)                                                                                                                                            Time  (rounds  of  the  game)      Examine  the  two  graphs  above.    Describe  the  effect  that  predators  have  on  the  populations  of  deer.              Briefly  try  to  explain  WHY  predators  have  this  effect.    Think  about  what  you  saw  in  the  game  and  what  you  noticed  in  the  graphs  when  you  are  figuring  this  out.        When  invasive  species  move  into  new  territories,  they  often  lack  natural  predators  in  the  ecosystem.    Based  on  what  you  saw  in  the  game,  what  can  happen  to  the  population  of  an  invasive  species  right  after  it  is  introduced  into  a  new  habitat?        Based  on  this  game,  what  do  you  think  is  one  strategy  that  humans  could  try  to  help  control  the  population  of  an  invasive  species  once  it  has  been  released?      

 Homework  Wednesday  March  27,  2013  Label  each  of  the  following  as  biotic  (B)  or  abiotic  (A):  • Wolf  • Rock  • Grass  

• Carbon  • Trees  • Sunlight  

• Humans  • Oxygen  

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• Bacteria  

 

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Label  the  type  of  ecological  relationship  demonstrated  by  each  of  the  following  scenarios:      • a  fish  follows  around  a  shark  to  feed  of  the  scraps  it  doesn’t  want    • a  wolf  hunts  down  and  eats  a  deer    • a  bird  eats  the  ticks  on  a  cow  for  food  • a  mosquito  bites  you  and  gives  you  malaria  

 What  is  the  difference  between  a  population  and  a  community?              What  shape  does  a  normal  growth  curve  have?    Why  does  it  stop  growing  and  what  do  we  call  the  maximum  number  of  organisms  an  environment  can  handle?              What  often  happens  to  populations  when  a  non-­‐native  species  is  introduced?    Why?            Why  are  predators  so  important  to  an  ecosystem?          What  process  creates  oxygen?    What  process  uses  oxygen?    Where  is  most  of  the  oxygen  on  Earth?          How  are  the  oxygen  and  carbon  cycles  linked?    Draw  the  two  cycles  below  and  label  the  processes:                    

 

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 Draw  the  three  steps  in  the  nitrogen  cycle  and  describe  what  happens  in  each  step?                    Why  do  humans  need  nitrogen?      Ph.D.  Extra  Credit  Summarize  the  following  article  for  extra  credit  points.  In  Guyana,  Wildlife  Makes  a  Slow  Return  By LESLEY DE SOUZA

Dr. Lesley de Souza, a research biologist at John G. Shedd Aquarium, writes from Guyana, where she studies the

region’s rich aquatic wildlife, including the arapaima, one of the largest freshwater fishes in the world.

Feb. 2, 2013

Matt de PaolisRudy Edwards, one of the Eco-Lodge managers, traveling on the Rewa River.

The candle flame flickered as a slight breeze moved through the benab, a thatched roof

hut, causing Rudy Edward’s illuminated face to fade

in and out of sight. We were gathered around a

wooden table listening as he recounted stories of a

time when “there were no signs of turtles, birds

flying overhead or arapaima rolling.”

A decade ago, the Rewa River was a very different place. Arapaima were

illegally hunted and killed. A local delicacy prized for their boneless, meaty

fillets, the fish were already endangered. Rudy, one of the top hunters and

fishermen in the village, admitted that harvesting local wildlife was the main

source of income for him and many families until a conservation workshop

transformed him.

 

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He attended the meetings not realizing they were for conservation and confesses that he did not even know what the

word conservation meant. Never before had he realized that he was directly having an effect on natural resources.

He imagined how it would be if his children never saw an arapaima or some of the other wildlife he harvested and

was dismayed. After the workshop, he continued to participate in groups working with conservation and began

taking the message back to his village.

“The challenges were great,” he told me. “It was difficult to change their way of thinking and living, in regards to

harvesting wildlife, especially as it was a main source of income for many families.” Slowly change became evident.

Commercial harvesting was banned in the village and new generations were growing up with the message of the

importance of preserving their natural resources.

Liz SmithThe giant water lily is the largest lily in the world and the national flower of Guyana. Arapaima are often found swimming among these flowers.

Today the Rewa River drainage has the highest densities of arapaima

populations in all of Guyana, making it the best site for my research.

My crew’s knowledge of arapaima and their behavior, originally gained

from hunting animals, is now a vital part of the research that could

protect these areas. I attribute the successes of the surgeries to their

keen perception and swift action. They guide like hunters and know every contour of the river channel and the

arapaima’s preferred habitat. They seem to have a nuanced understanding of the fish’s movement. Rudy even spoke

of arapaima behavior in ways I had never seen documented in scientific literature.

Rewa villagers have told me that getting involved in research offers them an opportunity to be directly involved in

conserving their resources. Additionally, Rewa villagers have established an Eco-Lodge where the flora, fauna and

cultural heritage are the main attraction. Here, the level of tourism is on a small scale. But ecotourism in Rewa is

still providing a direct benefit to the community by increasing awareness of its incredible biodiversity and generating

a sustainable stream of revenue for its people.

Liz SmithA tapir, also known as a bush cow among locals.

Conservation is occurring at the local level, but in order to continue to

protect arapaima the message must expand to the regional and national

level. It is critical to have good science to inform governing officials

about the proper management of natural resources. For now, good

science involves swimming in murky waters wrestling fish as long as I

am tall, amid the plethora of other incredible creatures that make Rewa

among the wildest places on earth.

The flickering flame is finally extinguished as the candle has melted completely onto the table. Silence envelopes the

air as we acknowledge the end of the evening. My eyes adjust to the darkness and I see a shimmer of the flowing

river reflecting the stars above; a place so wild that stars illuminate a moonless night.

 

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