Transcript Ecology - Yorba Linda High School

Ecology
Chapters 3-5
I. ECOLOGY = study of
interactions among organisms
& their environment
A. Environmental Factors
1. Abiotic Factors = nonliving
parts of environment
Ex: temperature, water, soil,
sunlight, rocks, wind, etc.
2. Biotic Factors = all LIVING
(or once living) organisms in
environment
3. Habitat = AREA an
organism lives in
Ex: forest, ocean
*organism’s address
4. NICHE = ROLE an
organism has in its
environment
Ex: finding food/shelter,
how/when it reproduces,
how it survives
* organism’s lifestyle
B. Ecological Levels of
Organization
1. Organism/Individual
2. Population = organism of
same species living in one
place at one time
3. Community = different
populations interacting
4. Ecosystem = interactions
of community & abiotic
factors
5. Biome = group of
ecosystems w/ similar climate
6. Biosphere = Earth [from
atmosphere to oceans]
C. Relationships Between
Organisms
1. Predator-Prey (+ -) = one
kills & feeds off another
Ex: Lions & zebras
2. Symbiosis = close &
permanent relationship
between 2 organisms (no
killing)
a. 3 Types of Symbiosis:
1. Mutualism (+ +) = both
species benefit
Ex: bees & flowers,
sharks & remora,
clownfish &
anemone
2. Commensalism (+ 0) =
one species benefits; other
has no benefit but no harm
Ex: Barnacles on a whale
Cattle Egrets & Livestock
3. Parasitism (+ -) = one
species benefits; other is
harmed
Ex: fleas on a dog,
tapeworm/ lice and
human
D. Organisms & Energy
1. Autotrophs (Producers) –
make own food
2. Heterotrophs (Consumers)
– feed on other organisms
a. Herbivores – eat plants
b. Carnivores – eat animals
c. Omnivores – eat both
3. Scavengers – feed on dead
animal bodies
Ex: vultures, hyenas
4. Decomposers – break
down & absorb nutrients from
dead organisms
Ex: bacteria, fungus
E. Energy Flow in
Ecosystems
1. Food chain – shows
ONE path of energy flow
2. Food web – shows
ALL possible
feeding/energy
relationships
3. Comparison
• Both start w/ PRODUCERS
• Food webs are more
realistic than chains
• Each step is called a
TROPHIC LEVEL
• Arrows show DIRECTION
OF ENERGY FLOW – NOT
what the organism eats!!
http://staff.harrisonburg.k12.va.us/~gharper/bay/weboflifepage/foodweb.jpg
4. Energy pyramids –
shows amount of energy
passed on in a food chain.
• bottom of pyramid is
producers -most plentiful
& has most energy!
• less energy available to
pass on to next level
(approx. 10% passed
onto next level)
II. Ecosystems Chap 4-2
A. Succession = natural
changes in an ecosystem
over time
• Occurs in stages
1. Primary succession –
development of community in
an area w/ no life
a. Ex: land after volcanic
eruptions, avalanches, etc.
b. NO SOIL/Pre-existing Life
c. LONG time to develop
d. Pioneer community –
species to live in area
• small, fast-growing &
reproduces fast
• Ex: lichens, mosses,
small animals
st
1
2. Secondary succession –
development of community in
a disrupted area
a. Ex: land after fires,
forest clearing, etc.
b. HAS SOIL
c. SHORTER time to
develop
d. Climax community –
final, stable community
w/ little or no change
Cycles of Matter
chap 3-3
* Matter is recycled
within and between
ecosystems
I. Cycles of Matter
A. WATER CYCLE
1. EVAPORATION
(TRANSPIRATION if H2O
lost from plants)
2. CONDENSATION
(forms clouds & droplets)
3. PRECIPITATION (rain,
snow, ice)
* IMPORTANCE = all living
things need water to survive
Condensation
Precipitation
Evaporation
Transpiration
Runoff
Seepage
Root
Uptake

The Water Cycle
B. CARBON CYCLE
1. CO2 released by
volcanoes, human activity,
respiration, decomposition
2. Photosynthesis uses CO2
to make glucose
3. Glucose (C6H12O6 eaten
by consumers for energy)
4. Organisms release CO2
through respiration
* IMPORTANCE = needed
in photosynthesis to make
O2, & needed for living tissue
& skeletons
CO2 in
Atmosphere
CO2 in Ocean

The Carbon Cycle--Recycling matter
C. NITROGEN CYCLE
1. N2 gas converted to
NH3/ NO3 / NO2 by bacteria
in soil for plants
2. Plants use NO3 / NO2 &
consumers eat plants to
make proteins
3. Dead organisms & animal
waste returns nitrogen to soil
4. Different bacteria in soil
convert this to N2 & release
into atmosphere
* IMPORTANCE = make
amino acids for proteins

The Nitrogen Cycle
D. PHOSPHORUS CYCLE
1. Phosphate in rock & soil
wears down into plants &
oceans
2. Plants & consumers take
in phosphate
3. When plants/animals die,
phosphate enters sediment
* IMPORTANCE = helps
form DNA & RNA

Phosphorus video clip
I. Populations- Chap. 5
A. Population size depends
on: 1) # of births
2) # of deaths
3) Migration
(immigration &
emigration)
Ex. Sea otter population
decreased when death
rate increased due to
hunting
 Shortage of food supply
can cause emigration &
decrease population

B. Exponential Growth (J-shape):
1. Slow initial growth -very
few organisms to start
2. Rapid growth over time #
of organisms reproducing
increases
only if resources are
unlimited
Exponential Growth
http://www.agen.ufl.edu/~chyn/age2062/lect/lect_27/39_05.GIF
C. Logistic Growth (S-shape):
1. Occurs if resources
reduce, -population
growth will slow or stop
• Growth levels off at
CARRYING CAPACITY = largest
# of organisms of a species the
environment can support
Logistic Growth
http://www.algebralab.org/img/cb07ae0c-5106-416c-8407-38da526923c6.gif
D. Limits to Population Growth
1. Limiting factor = biotic or
abiotic factors that restricts #
of organisms
a. Types of Limiting Factors:
1. Density-dependent = as
population increases, the
effect will increase
a. Predation – as prey ,
predators
& vice versa
b. Disease & parasitism

Makes individuals weak
and more likely to die
c. Competition for resources
•Survival of the fittest

Ex. Puffins & their nesting
site
2. Density-independent =
affects all populations
regardless of size
a. Natural disasters
b. Weather/climate
c. Human activity
(pollution, clearing forests,
etc.)