Download Marine Ecology

Ecology –how & why organisms interact
with each other & with environment
Levels of Biological Organization
1. Species – group of similar organisms; successfully
interbreed
2. Population – members of same species living in
same area @ same time
Levels of Biological Organization
3. Community – all populations living together &
interacting
4. Ecosystem – a community together w/ abiotic (nonliving) part of environment
Populations
How Do We Determine How Populations
Change In Size?
Growth rate (r) – birth rate minus death rate
r=b-d
r = (+), r = (-), r = (0)
Types of Population Growth
What type of growth is this?
Types of Population Growth
Exponential pop. growth (J curve) –occurs
when optimal conditions allow a constant
growth rate
Types of Population Growth
The larger the pop. gets, the faster it
grows, doubling each time.
Types of Population Growth
What type of growth is this?
Types of Population Growth
Logistic population growth (S curve) –
initial exponential increase, levels out as
carrying capacity is reached
What’s Carrying
Capacity (K)?
Types of Population Growth
Logistic population growth (S curve) –
initial exponential increase, levels out as
carrying capacity is reached
Carrying capacity (K)
The largest
population that can
be supported by
available resources.
Effects of a Limiting Resource in a
Population
Human Population
What kind of growth?
http://www.census.gov/main/www/popclock.html
l
Reproductive Strategies
r-selected species (opportunistic) – have traits
that contribute to high population growth rate (r)
Examples of r-selected species?
Characteristics that r-selected species would
have?
Reproductive Strategies
r-selected species (opportunists) – traits that
contribute to high population growth rate (r)
Examples of r-selected species?
Characteristics that r-selected species would
have?
Reproductive Strategies
K-selected species – have traits that maximize
chance of surviving in environment where # of
individs. is near carrying capacity (K)
Examples of K-selected species?
Characteristics that K-selected species would
have?
Communities
Types of Interactions
Predator/Prey Interactions
What do predators tend to prey on?
Why are predator/prey interactions important?
Predators prey on weak and sick, forcing prey to
become more fit
Predators are forced to become more fit.
Affects fitness of organisms!
Why are predator/prey interactions important?
How is predator affecting prey and vice versa?
Why are predator/prey interactions important?
Controls abundances of organisms!!
Why are predator/prey interactions important?
How is predator affecting the number of
species in intertidal (tide pool) community?
Why are predator/prey interactions important?
Predators keep prey #’s in check so prey will
not out compete each other and form a
monoculture and lower species diversity.
Predator in Kelp Forest Community:
Sea Otter
Kelp Forest Community
Major Grazer of Kelp: Sea Urchins
Urchin Barrens
Urchin Predators In Kelp Forest
Community
What happens to
this food web if
we remove
predators?
Algae & Seastar Consumers in
Coral Reef Community
Giant
Triton
Coral Killers
Crown of Thorns
seastar
Overgrowth of
algae
What will happen if these species disappear
from a community?
Types of Interactions
Symbiosis “living together”– any association
between 2 or more species
Types of Interactions
Competition – occurs when 2 or more individuals
use an essential, limited resource
What is the outcome
of head to head
competition?
Competitive
exclusion - 1 species
is excluded from
portion of
community by
another
Resource
partitioning –
differences in
resource use among
species; dividing the
resource
Shorebird Bill Shapes & Feeding
Strategies
Ecosystems
How energy flows in ecosystems
What is being
given off at each
level?
Food Chains – energy moves from one
organism to the next in a sequence (one
way flow)
Rarely exists in nature
Food web- complex of interconnected food
chains
More likely in
nature
Trophic level- each level in the food chain
At each level heat is given off that
is unavailable to next level
Energy Pyramids
Displays amount of living material
(energy) available at each trophic level
Why is there a stepwise decline of
biomass as you go up levels?
How much energy will be transferred to the animal
that eats the caterpillar?
Heat
Heat
Most consumed energy goes towards cellular
respiration and lost as heat and waste
Only a small amount goes toward actual growth
(stored energy) and is transferred to next level
Only a small amount goes toward actual growth
(stored energy) and is transferred to next level
So, is there more energy available at the higher or
lower levels?
Why more zebras than lions?
www.animals.timduru.org
www.game-reserve.com
Why more krill than orcas?
Because of stepwise decline, more energy is
available to lower level consumers and higher
numbers of them can be supported.
What type of consumer is more “expensive” for
an ecosystem to support? Why?
How many levels do high level consumers
consume compared to low level consumers?
Carnivores are “expensive” to support because
they “consume” more levels !
Why can certain animals at lower trophic levels be
much larger in size than carnivores?
www.animals.timduru.org
Because of stepwise decline, more energy is
available to lower level consumers and larger sized
animals can be supported.
www.animals.timduru.org
Because of stepwise decline, more energy is
available to lower level consumers and larger sized
animals can be supported.
www.sps.nus.edu.sg
www.hoglezoo.org
Whose at a higher
trophic level, the
orca or the baleen
whale?
So what will be
able to be larger
in size?
Fig. 9.18
Fig. 8.5
Vegetarians vs. Meat Eaters
What level is consuming more energy & is
more expensive for an ecosystem to
support?
Vegetarians vs. Meat Eaters
Takes 10 lbs of feed corn to produce 1 lb of
bacon or beef steak
Being meat eater is an inefficient way of
using photosynthetic productivity (energy)