100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
BIOLOGY281: ALL lecture and textbook notes $25.49   Add to cart

Class notes

BIOLOGY281: ALL lecture and textbook notes

 1 view  0 purchase

CUMULATIVE textbook and lecture notes for the class BIOLOGY281: General Ecology at the University of Michigan. Notes were taken WN2024 under Prof. Christopher Dick.

Preview 4 out of 126  pages

  • August 2, 2024
  • 126
  • 2023/2024
  • Class notes
  • Christopher dick
  • Biology 281: general ecology
All documents for this subject (1)
avatar-seller
gloriakawai
Chapter
1:
What
is
Ecology
in
Action?
1.1
Ecological
Questions

2
basic
questions
asked
by
population
ecologists:

What
is
the
abundance
of
a
population?

What
is
the
distribution
of
the
population?
1.2
Testing
Hypotheses

To
be
study-worthy,
hypotheses
must
be
plausible
and
generate
testable
predictions

Consider
all
hypotheses
when
attempting
to
understand
a
biological
process

Hypotheses
for
buffalo/wildebeest
population
increase
in
the
1960s/1970s:

Food
Availability
Hypothesis:
food
was
better
in
quality
or
more
abundant

Rainfall
influences
grass
production

To
test:
established
exclosures
(experimental
fenced
areas
that
reduces
unwanted
factors)

Harvested
vegetation
within
exclosures
regularly
and
measured
the
amt
of
grass
that
grew
compared
to
the
amt
of
rainfall

Predicted
positive
correlation
between
rainfall
and
grass
production

As
rainfall
increased,
grass
production
also
increased

significant
positive
effect
on
grass
availability

Rainfall
records
were
the
same
as
historical
averages

likely
not
the
reason
for
population
increase

Predator
Release
Hypothesis:
reduction
(release)
from
high
levels
of
predation

To
test:
compared
previous
surveys
of
predator
levels

Found
that
predator
populations
also
increased
during
this
time

Rinderpest
Release
Hypothesis:
rinderpest
is
a
virus
that
attacks
cattle
and
other
ruminants
(mammals
who
digest
plant-based
food
by
softening
it
within
the
rumen
where
it
ferments)

Great
Rinderpest
Plague
of
1890
killed
95%
of
cattle
in
southern/eastern
Africa

Hypothesized
that
rinderpest
was
keeping
wildebeest
and
cattle
populations
unnaturally
low
in
the
50s,
and
that
they
were
recovering
in
the
60s

When
both
variables
are
numeric
or
continuous,
use
correlation
analysis
to
eval
relationship
b/n
them

Statisticians
use
the
correlation
coefficient
(r)
to
describe
correlation
strength

1.0
=
strong
positive,
-1.0
=
strong
negative,
0
=
no
correlation 1.3
Observation,
Modeling,
and
Experimentation

Ecology
happens
in
the
real
world

Controlling
variables
is
difficult

Replication
of
experiments
may
be
impossible

Must
be
able
to
observe
and
pick
up
on
small
nuances

3
types
of
observations

Observe
actual
processes
with
their
senses

Learn
from
published
literature

Observe
what
other
people
are
doing
or
saying

Local
communities,
other
scientists/experts
from
other
fields,
bouncing
ideas
off
of
other
ecologists

Scientific
models
seek
to
describe
a
system
or
predict
what
it
will
do
in
the
future

Ecologists
differ
from
other
biology
fields
because
their
research
spans
and
integrates
many
levels
of
the
biological
hierarchy
1.4
Linking
the
Biological
Hierarchy

Ecologists
study
interactions,
so
must
understand
all
levels
of
the
biological
hierarchy
but
usually
focus
on
the
level
of
the
organism
and
above,
up
to
the
biosphere

Can
use
the
Serengeti
to
represent
the
different
levels
of
the
biological
hierarchy

Organism:
individual
life
form

At
this
level,
can
ask
how
individual
buffalo
forages
in
a
manner
that
meets
its
daily
energy
and
nutritional
needs

Can
explore
distribution
and
abundance
of
populations
at
a
location

Wildebeest,
zebra,
and
Thompson
gazelle
migrations

Populations
interact
to
form
communities

Wildebeest
grazing
stimulates
regrowth
of
grasses/plants

gazelles
and
other
populations
can
eat
them

Communities
of
wildebeest,
gazelles,
grasses,
and
plants
all
interact

The
ecosystem
includes
all
communities
and
abiotic
features
that
interact
with
each
other

Landscapes
are
interacting
and
spatially
connected
ecosystems

West
of
the
Serengeti,
ecosystem
is
dominated
by
agriculture

Humans
hunt
elephants,
wildebeests,
etc

Landscapes
are
parts
of
larger
regions
with
common
set
of
environmental/evolutionary
influences

On
this
level,
look
at
abundance
and
species
richness

The
biosphere
is
the
highest
level;
the
part
of
the
world
that
supports
life

3
primary
abiotic
factors
studied
in
the
Serengeti:

Nutrients

Highest
levels
in
the
southeastern
plain

Lowest
in
the
northwest

Fire ■
Almost
all
started
by
humans

Improve
grazing
pastures,
park
management,
honey
hunters
smoking
out
bees

Only
occur
in
dry
season
but
in
typically
wetter
areas

Wetter
area

more
grass
growth

more
dry
grass
for
fuel
in
the
dry
season

Rain

Lowest
levels
in
the
southeastern
plain

Highest
in
the
northwest

Due
to
rain/nutrient
levels,
migrating
animals
spend
the
wet
months
in
the
southeast,
then
move
to
the
northwest
in
the
dry
season

Distribution
of
abiotic
factors
influences
distribution
of
organisms

Much
of
the
western/northern
portion
of
the
Serengeti
is
open
woodland
with
canopy
cover
b/n
2%
and
30%

Grass
grows
easily
between
the
trees

El
Nino
Southern
Oscillation
(ENSO)
:
a
large-scale
atmospheric
system
that
affects
the
global
climate

Associated
with
high
temperature
and
low
pressure
in
the
Pacific
region

Affects
Serengeti
climate

Fluctuates
~5
years
Lecture

1/16

Scientific
Method

Make
observations,
ask
questions

Previous
knowledge/intuition

form
hypotheses

Evaluate
hypotheses
by
experiment,
observation,
or
modeling

Use
results
to
modify
hypothesis,
pose
new
questions,
or
draw
conclusions

Scientific
method
is
iterative
and
self-modifying

Serengeti:
79
large
mammal
species

Southeast
and
northwest
corners
=
wet
areas

In
between
is
very
dry

Breeding
season
spent
in
southeast,
migrate
to
northwest
during
dry
season

60s-70s:
wildebeest
population
growing
rapidly…
why?

Tony
Sinclair’s
hypotheses:

Food
availability:
more
rain
=
more
food/higher
quality
food
available

Prediction:
food
quality
and
abundance
increased
in
early
60s
and
remained
high
throughout
the
decade

Test:

Use
exclosures
to
test
productivity
of
grasslands
in
areas
with
increased
rainfall

Determine
if
rainfall
had
increased
significantly
over
the
period
of
population
increase ■
Was
not
found
to
be
true

Predator
release:
less
predators
=
more
survival

Prediction:
large
predators
declined
in
the
60s

Test:
look
at
records
of
predator
populations

Not
found
to
be
true

Rinderpest
release:
rinderpest
was
a
disease
that
affected
cattle
and
other
ruminants,
rinderpest
eradicated
so
wildebeest
populations
rebounded

Predictions:

Negative
correlation
between
rinderpest
infection
and
ruminant
abundance

No
correlation
between
rinderpest
infection
and
non-ruminant
abundance

Increased
survival
rate
in
juvenile
ruminants

Kinds
of
experiments

Lab:
control
everything,
possibly
reductionistic

Field:
can
manipulate
things
but
maybe
not
“natural”

Natural:
may
have
confounding
factors

Rules
of
experimental
design

Replication

Randomization

Avoid
pseudoreplication

False
positive

type
I
error

Incorrectly
reject
the
null

False
negative

type
II
error

Incorrectly
accept
the
null

Types
of
data

Categorical:
finite
number
of
categories/groups

Discrete:
numeric
variables
that
have
countable
number
of
values,
no
decimals

Continuous:
numeric
variables
w/
infinite
number
of
values
between
any
two
values

What
kind
of
test?

Independent:
Quantitative;
Dependent:
quantitative

correlation
or
regression

Ind:
Categorical;
Dependent:
quantitative

T-test,
ANOVA

Ind:
categorical;
dependent:
categorical:
chi-squared
Chapter
2:
The
Physical
Environment
Intro

Biome:
large
geographical
area
w
characteristic
groups
of
organisms
adapted
to
that
particular
environment

Terrestrial
biomes
influenced
by
temp,
moisture,
and
soil

Aquatic
biomes
influenced
by
temp,
chemical
composition
of
water,
and
currents

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller gloriakawai. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $25.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

79271 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
$25.49
  • (0)
  Add to cart