ap bio: monday, 12.20.10 unit 7: ecology
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AP Bio: Monday, 12.20.10 Unit 7: Ecology. Homework: Decide which biome you will do for your project Finish reading and taking notes on Chapter 54 Do Now: How do you define ecology ? Goals for Today: Describe the differences between the way that energy and nutrients move through ecosystems - PowerPoint PPT PresentationTRANSCRIPT
AP Bio: Monday, 12.20.10Unit 7: Ecology
Homework: Decide which biome you will do for your project Finish reading and taking notes on Chapter 54
Do Now: How do you define ecology?
Goals for Today: Describe the differences between the way that
energy and nutrients move through ecosystems Define and explain primary productivity and explain
what factors influence it Agenda:
Introduce Biome Project Lecture: Intro to Ecology
Ecology - • The study of interactions between organisms
and their environment– other organisms – abiotic factors
Big Themes of this Unit:• Energy flow – in one direction, and inefficient
transfer• Nutrient cycling (my waste = your food)• Interdependence (within populations, and
between species [food webs])• Human impacts on ecosystems
Ecosystems Ecology
Ecosystem – all the organisms and abiotic factors in a given area
Ex:• a hardwood forest ecosystem in central MA• a freshwater pond
Ecosystem components interact through transfers of energy and nutrients.
What do the following images show concerning
energy flow vs. nutrient cycles?
Energy Flow:• One-way series of energy
transfers:Solar energy
Chemical energy stored in organisms
Heat energy• Inefficient transfer at each
step (1% - 20% transferred; the rest is used for metabolism & ultimately lost as heat)
• Energy can’t be recaptured or used again once it’s lost as heat
Nutrient Cycling:• Cyclic transfer of nutrients
between biotic and abiotic components
Soil/water Producers
DecomposersConsumers
• All atoms are continually recycled – no net inputs or outputs in the biosphere
Energy Transfer is Inefficient…
Energy Pyramid:
1% of solar energy captured by primary producers
~ 10% of energy transfer between each trophic level
Foundation of the Food Web: Primary Productivity
PP = the amount of light energy converted to chemical energy (organic compounds i.e. sugars) by producers (autotrophs) in a given time periodCan be thought of as…– The amount of photosynthesis done– The amount of carbon fixed
Gross PP = total amount
Net PP = total amount minus the energy used for cell respiration by the producers themselvesNPP = GPP – Resp.
Global NPP: What influences it?
Primary Productivity inAquatic Ecosystems
• Limited by availability of…– Light– Nutrients
• How do we measure aquatic PP? (this week’s lab)
6C02 + 6H20 C6H12O6 + 602
• Oxygen produced during photosynthesis dissolves in water – DO2
• Measuring DO gives a measure of PP
AP Bio: Tuesday, 12.21.10Nutrient Cycles
Homework: Work on your biome project
Do Now: What powers the water cycle?
Goals for Today: Explain how water, carbon, and nitrogen cycle
through ecosystemsAgenda:
Hand back tests Lecture/Discussion of Notes: Nutrient Cycles Practice MCQs
Nutrient CyclesWater Cycle: Carbon Cycle:
Nutrient CyclesNitrogen Cycle:
How Does Nutrient Availability Affect Aquatic Ecosystems?
How Does Nutrient Availability Affect Aquatic Ecosystems?
• Eutrophication – process in which aquatic ecosystems become (overly) full
of nutrients like N, K, and P• Allows algae to grow (too) prolifically algae bloom• Algae blocks sunlight for other plants• Algae die and decomposer bacteria eat them and
flourish• Bacteria use up all the DO2
• None left for fish and other organisms they die ocean dead zones
Interactions between Organisms and Nutrients: The Hubbard Brook Experiment
• Cut down all trees, measure nutrients in run-off water
Conclusions?– Trees help hold nutrients in the ecosystem!
Interactions between Organisms and Nutrients: The Hubbard Brook Experiment
AP Bio: Wednesday, 12.22.10Population & Community Ecology
Homework: Work on your biome project
Do Now: Get a laptop
Goals for Today: Identify the key characteristics and major species of your
biome or ecosystem Apply ecological concepts to a particular biome or ecosystem Describe the factors that influence population growth in a
species Identify types of interactions between species in a community
Agenda: Period 1: Work on Biome Project Period 2: Lecture – Population & Community Ecology
Population Ecology
“Life history strategies” - based on reproductive strategies
Two extremes:
The Fast and the Furious/ Slow and Steady
The Young and the Restless
Survivorship Curves
Fraction of Survivors
Max. Life Span
Population Growth:
• Determined by birth rate and death rate• Density-dependent factors limit population growth
– Resources (food, nutrients, light, habitat/territory)– Disease– Aggressive behavior
• Density-independent populations – birth and death rates don’t change with increasing population size
Two Models for Population Growth
(1) ExponentialGrowth
dN/dt = rN
• r-selected populations (r = growth rate; this determines pop. growth)
(2) Logistic Growth
dN/dt = rN([K-N]/K
K = Carrying Capacity -
The maximum population size that an ecosystem can sustainably support over time
K-selected populations – carrying capacity determines population size
Human Population Growth
• Exponential or logistic?• What is Earth’s carrying capacity for
humans?
Community Ecology(interactions between species)
• Niche – – The particular role that a species plays in its
community• Food, predators, micro-habitat, active time of day
• Interactions between species can be positive, neutral, or negative
+/+ +/n +/- -/-
• Competition - – Species compete for food, water, light,
habitat– Occurs when niches overlap– Introduced / “Exotic Invasive” Species –
often outcompete native species
AP Bio: Thursday, 12.23.10Ecological Succession
Homework: Work on your biome project Have a great vacation!
Do Now: If the clear-cut area shown above were left
alone (no more trees cut) for 20 years, how do you think the community of species would change over time?
Why? What do you think the phrase “ecological
succession” means?
AP Bio: Thursday, 12.23.10Ecological Succession
Goal for Today: Predict how and why ecological communities
change after a disturbance
Agenda: Partner Practice-Quiz: Free Response
Question Grade question and discuss succession Finish up lecture from yesterday
(Sorry, we couldn’t get computers for today… )
AP Bio: Monday, 1.3.11Welcome Back & Happy New Year!
Homework: Lab 12 Pre-Lab (#1-5) Do Now: (please write this in your
notebook)(1) Describe one cool thing you did or learned over
the break.(2) Do you want to present your biome project to the
whole class?(3) What is primary productivity? (check your notes
for a reminder) Goals for Today:
Define and explain primary productivity Identify key characteristics of major biomes
Foundation of the Food Web: Primary Productivity
PP = the amount of light energy converted to chemical energy (organic compounds i.e. sugars) by producers (autotrophs) in a given time periodCan be thought of as…– The amount of photosynthesis done– The amount of carbon fixed
Gross PP = total amount
Net PP = total amount minus the energy used for cell respiration by the producers themselvesNPP = GPP – Resp.
Global NPP: What influences it?
Primary Productivity inAquatic Ecosystems
• Limited by availability of…– Light– Nutrients
• How do we measure aquatic PP? (this week’s lab)
6C02 + 6H20 C6H12O6 + 602
• Oxygen produced during photosynthesis dissolves in water – DO2
• Measuring DO gives a measure of PP
AP Bio: Monday, 1.3.11Biome Projects
Homework: Lab 12 Pre-Lab (#1-5)
Goals for Today: Define and explain primary productivity Identify key characteristics of major biomes
AP Bio: Tuesday, 1.4.11Dissolved Oxygen Lab
Homework: Lab 12 Part A – Graph and analysis
Do Now: Take out Lab 12
Goals for Today: Experimentally determine how temperature affects
the dissolved oxygen content of water
Agenda: Lab!
AP Bio: Tuesday, 1.4.11Lab 12 Part B: Primary Productivity
Homework: None Do Now:
Take out Lab 12 and turn to page 8 Goals for Today:
Set up an experiment to determine how water depth (aka % light) affects primary productivity of aquatic algae
Agenda: Review Lab 12 Part A Biome Presentation Pre-Lab for Part B Set up Part B Biome browsing
• Predation– One species eats another– Predator adaptations– Prey adaptations
• Cryptic coloration• Toxins and warning coloration• Mimicry
• Predator-prey population cycles
Keystone Species
Biologicalmagnification