Day 21 Chapter 15 November 25th

Dr Amy B Hollingsworth

The University of Akron

Fall 2014

We only have 2 classes left!

• Today – teacher evaluations, Homework CH 15

• Thursday – Turkey Day, no class

• Tue Dec 2nd – Finish Chapter 15

• Thur Dec 4th – Chapter 16

• Final – Dec 11th – CBT, will be open from noon to 7pm.

• Any makeup exams for excused absences will be Dec 8th – 10th, in the CBT, by appointment only

Chapter 15: Ecosystems and Communities

Organisms and their environments

by Mark Manteuffel, St. Louis Community College

15.1–15.2

Ecosystems

have living and

nonliving

components.

15.1 What are ecosystems?

A community of biological organisms plus the non-living components with which the organisms interact.

15.2 A variety of biomes occur around the world, eachdetermined by temperature and rainfall.

Biomes What is the average temperature?

What is the average rainfall (or other precipitation)?

Is the temperature relatively constant or does it vary seasonally?

Is the rainfall relatively constant or does it vary seasonally?

Biomes Temperature and precipitation dictate:

• Primary productivity levels

the amount of organic matter produced

The numbers and types of primary producers:

• are the chief determinants of the amount and breadth of other life in the region.

15.3–15.5

Interacting

physical forces

create weather.

15.3 Global air circulation patterns create deserts and rainforests.

15.4 Local topography influences the weather.

Is it warmer or cooler in urban areas relative to nearby rural areas?

“Urban Heat Islands”

Why is it so windy on streets with tall buildings?

15.5 Ocean currents affect the weather.

Global patterns of circulation in the oceans

Why do beach communities have milder weather than more inland communities?

Water’s capacity to absorb and hold heat

Beaches on the east coast of the United States have warmer water than west coast beaches at the same latitudes.

Why?

15.6–15.8

Energy and

chemicals flow

within

ecosystems.

15.6 Energy flows from producers to consumers.

First Stop: Primary Producers

Second Stop: PrimaryConsumers—the Herbivores

Third Stop: Secondary Consumers—the Carnivores

Fourth Stop: Tertiary Consumers—the “Top” Carnivores

Chains or Webs?

Food chain

• Pathway from photosynthetic producers through the various levels of animals

Food web

• Involve harvesting energy from multiple stops in the food chain

Energy Flows

Losses at every “step” in a food chain

Inefficiency of energy transfers

15.7 Energy pyramids reveal the inefficiency of food chains.

10% efficiency

Biomass 10% rule

Where does the rest go?

Expended in cellular respiration or lost as feces

In humans, why is vegetarianism more energetically efficient than meat-eating?

The 10% rule in application

Why are big, fierce animal species so rare in the world?

15.8 Essential chemicals cycle through ecosystems.

The recycling of molecules

Chemical Reservoirs Each chemical is stored in a non-living part of the

environment.

Organisms acquire the chemical from the reservoir.

The chemical cycles through the food chain.

Eventually, the chemical is returned to the reservoir.

The Three Most Important Chemical Cycles

1. Carbon

2. Nitrogen

3. Phosphorus

Why are global CO2 levels rising?

Fossil fuels

Global CO2 levels are rising in general, but they

also exhibit a sharp rise and fall within each year.

Why?

Nitrogen is like a bottleneck limiting plant growth.

Fertilizers

15.9–15.14

Species

interactions

influence the

structure of

communities.

Finally - Evaluations

• I need someone to volunteer to do the survey for this class.

• Be honest – what can I do to improve (seriously, besides just giving away grades like skittles)

• www.ratemyprofessor.com is the best way to let future students know what’s good or bad.

What to note -

• Did you like the technology for the class?

• Was I helpful or caring or a big nasty jerk?

• What did you think of the videos?

• Do you like that I post everything online?

• Do you think the material was too easy or too hard?

• What did you think of lecture versus lab?

• Would you take me again for a class?