Transcript Invasive Species

 Fighting/
competition
 Breeding
 Predator/
 Symbiosis
prey
Different
species compete for space
or resources
Causes animals to shift niches,
adapt, evolve, migrate, or go
extinct
Animals
become more specialized in
what they eat/ where they live,
when they are active
Resource partitioning
Character displacement
Resource
partitioning:
 Species
evolve ways to share limited
resources
Different times of day/ year
 Different uses
 Different places

Resource
Partitioning in
5 species of
Warbler
9-5
Resource partitioning via specialized
feeding niches:
Black skimmer
seizes small fish
at water surface
Flamingo
feeds on
minute
organisms
in mud
Brown pelican dives for fish,
which it locates from the air
Scaup and other
diving ducks feed on
mollusks, crustaceans,
and aquatic vegetation
Avocet sweeps bill through
mud and surface water in
search of small crustaceans,
insects, and seeds
Louisiana heron wades into
water to seize small fish
Dowitcher probes deeply
into mud in search of
snails, marine worms,
and small crustaceans
Oystercatcher feeds on
clams, mussels, and
other shellfish into which
it pries its narrow beak
Herring gull is a
tireless scarialavenger
Ruddy turnstone searches
under shells and pebbles
for small invertebrates
Knot (a sandpiper)
picks up worms and
small crustaceans left
by receding tide
Reduces competition and allows sharing of
limited resources
Piping plover feeds
on insects and tiny
crustaceans on
sandy beaches
Character
displacement:
 Organisms
change physical
characteristics to become specialized
 Finches develop different size and
shape beaks to reduce competition
Predator
eats prey species
Predators often feed on the old/
sickly/ weak/ least fit
 This
reduces competition among prey
Predators
control prey populations
Problem:
both hypotheses assume
too much.
 Top-down-
that lynx only eat rabbits
and rabbits are only eaten by lynx
 Bottom-up- that only rabbits eat
veggies
Says
that predators control prey
pops
Ex: Lynx eat rabbits so rabbits
decrease. Rabbits decrease so there
is less food for the lynx so the lynx
crash. Less lynx means less
predators so rabbits increase which
allows the lynx to increase.
Food
sources influence population
Ex: Rabbits eat too much vegetation
so there isn’t enough food. Rabbits
crash. Veggies grow back and then
rabbits increase.
Pursuit:
Fast runners, ability to see
from above, hunt cooperatively in
packs
 Ambush:
use camouflage to hide in plain
sight and surprise their prey
 Chemical
into prey
warfare: bite and inject venom
Run,
swim, fly fast
Highly developed sight/ smell/
hearing
Protective shells/ bark/ spines
Change colors
Mimicry
Camouflage
Chemical warfare
Mimicry
Behaviors
Plants
develop many defense
chemicals
Pepper, caffeine, cyanide,
cocaine, opium, strychnine,
peyote, nicotine, rotenone,
mustard, nutmeg, oregano,
cinnamon, mint
One
organism lives on or in another
organism and lives off of it
Some
parasites have a different host
for each life stage
Two
species acting together so both
benefit
 Pollination:
bees and flowers
 Nutritional: coral and zooxanthellae
 Food + protection: ox pecker birds and
rhinos
 Gut inhabitation: bacteria in termites/
humans to aid in digestion
Two
species interact and one
benefits while the other is basically
unaffected
Species
that are normally found in a
particular area and they thrive in
that environment
A
species that is not originally found
in that location
Some are harmful, others are
benign, others are helpful
A
non-native species that DOES NOT
harm it’s new environment
Usually plants
Ex: Goldfish
Any non-native specie of plants,
animals, etc that:
 Is
harmful to native critters
 Negatively affects it’s new environment
 Can hurt new environment economically
 Examples: zebra mussels, brown anoles,
African bees, Kudzu
 Zebra
mussels (Great
Lakes):
 Released
via ship
ballasts (1988)
 Filter
out nearly all the
phytoplankton (and
small zooplankton)
 Bad
and good
2004!
Asian
green mussels in Tampa Bay
African bees:
 Introduced into the wild
in South America (1956).
 The Africanized bee
escaped and began to
dominate honey bee.
 Kudzu
(from Japan)
Can
be on
purpose or on
accident
Monitor
lizards
and Burmese
Pythons in South
Florida/
Everglades
Pets that are
released when
they get too big to
handle safely
 Lionfish
in the FL
Keys
 Accidentally
introduced during
Hurricane Andrew
 Massive efforts are
underway to curb
the population
 Fishing, “delicacy”
at restaurants,
cookbooks
Species
that
serve as an
early warning
system for
damage/
danger/
pollution for a
community
Birds
and butterflies
Sensitive to environmental
changes
Both
bird and butterfly
populations are declining
worldwide…
Great
indicator
species
Super
vulnerable to
environmental
disruption at
different points
in their life
cycles
Eat
bugs (pesticides), no shell on
eggs (UV radiation), thin permeable
skin that easily absorbs pollutants
from the water and air
Not
just one thing
Declining in every region of the
world
Habitat loss, prolonged drought,
pollution, increase in UV radiation,
increased parasitism, & overhunting
1.
2.
3.
Tells us environmental conditions
are degrading
Amphibians are important parts of
ecosystems
They might have genetic secrets
humans want for Rx
Have
great effect on ecosystems
Loss can lead to population crashes or
even extinction of other species
Pollinators-
bees, hummingbirds,
butterflies, bats
Top predators- wolves, sharks,
bears, alligators
Waste management- dung beetles
Play
a major role in shaping the
community or habitat
Benefits other species
Ex: elephants knock down trees
which allow grasses to grow.
Antelopes eat the grass…



Physical appearance/ distribution
of species
Species diversity (Species richness
and evenness)
Niche structure (how many and
similarity)
What
does it mean if you say there
is high species richness but low
species evenness?
Latitude
 Highest
near equator
Pollution
 Net
(aquatic systems)
primary productivity
 Habitat disturbance
 Time
Species
Equilibrium Model
Rate at which new species
immigrate and established species
go extinct affects the number of
different species found on an island
Two
factors influence the extinction
and immigration rates:
 Size
of the island- smaller island =
fewer species therefore it has low
immigration and high extinction rates
 Distance from nearest mainlandAssuming equal rate of extinction on
two islands, one closer to mainland
will have higher immigration rates
Rate of immigration
or extinction
High
Low
Equilibrium number
Number of species on island
(a)
Immigration and extinction rates
Rate of immigration
or extinction
High
Low
Small island
Large island
Number of species on island
(b)
Effect of island size
Immigration
(near island)
Rate of immigration
or extinction
Extinction
Immigration
(far island)
Low
Far island Near island
Number of species on island
(c) Effect of distance from mainland
What
is a niche?
What is a fundamental niche?
What is a realized niche?
What
is a generalist species?
What is a specialist species?
Communities
change over time due
to disturbances and changing
ecological conditions
This gradual change is known as
ECOLOGICAL SUCCESSION
Two types: primary and secondary
Gradual
establishment of biotic
communities on nearly lifeless
ground
Takes a very long time
 Needs
soil!
Pioneer
species- first species attach
to bare rock, soil begins to gather
Lichens, mosses
Decompose and breakdown rock
Patches
of soil build up
Early successional plant species:
 Small
annuals (live only for 1 year)
 Small perennial grasses (live for at
least 2 years)
 Thrive in harsh conditions, grow
quickly
Lichens
and mosses are eliminated
Hundreds
to thousands of years
later…
Soil becomes deeper an contains
more nutrients
Midsuccessional plant species
 Herbs,
 Trees
grasses, low shrubs
Trees
grow up and make lots of
shade
Late successional plant species
 Mostly
trees
 Must be able to tolerate shade
Can
occur in small ponds
 Influx
of sediments can allow plants to
invade
 Turns into a marsh and then dry land
Natural
community has been
disturbed somehow
Soil still remains
Much faster than primary succession
Abandoned farmlands, cut/ burned
forests, polluted streams, land that
was dammed or flooded
Any
change in
environmental
conditions that disrupts
a community
Fire, drought, flooding,
mining, clear-cutting,
pesticides, invasion,
etc…
Not always bad
Plants
begin to grow back quicker
because of the soil already present
3
factors that affect the rate of
succession
 Facilitation-
one species makes area
habitable for other species
 Inhibition- early species hinder growth of
later species
 Tolerance- late successional species are
unaffected by earlier species
Study
of how populations change in
SIZE, DENSITY, and AGE
DISTRIBUTION
Clumping
Most
populations live in clumps
Why
live in clumps?
Resources vary from place to place
Living in a herd/ flock/ school
provides protection from predators
Predators are almost guaranteed a
meal
Some form temporary groups for
mating purposes
Uniform-
allows species to maximize
limited resources
 Random-
very few species are randomly
distributed
What
four factors determine change
in population size?
Hint: pop change= (? + ?) – (? + ?)
Pre-reproductive
Reproductive
Post-reproductive
Remember
the population pyramids?
Intrinsic
rate of increase (r)
 Rate
a population would grow at if it
had unlimited resources
Biotic
potential
 Capacity
for growth
Environmental
conditions within
species range of tolerance
Generalists
Easily adapt to change
Resistance to disease and predators
Enough food
Ability to migrate and live in other
areas
Individuals:
 Reproduce
early
 Reproduce often
 Have a lot of babies each time
 Have short generation times
Populations
cannot grow indefinitely
Environmental resistance- all the
factors that act to control
population growth
Environmental
conditions outside of
range of tolerance
Low reproductive rate
Specialists
Not enough food/ resources
Too many predators/ competition
Unsuitable habitat
Unable to change
K
Maximum
number of individuals of a
given species that can be sustained
indefinitely in a given space
Growth slows down as population
reaches K
Population
grows at a
fixed rate
Grows slowly at first
then growth explodes
Creates a J-shaped
population graph
Rapid
exponential population growth
followed by decline until population
levels off
What
happens when growth exceeds
K?
Overshoot- happens when population
exceeds K
 Due
to a reproductive time lag
 Birth rate must fall and death rate
must rise
Dieback
or crash UNLESS organisms
can change to another resource
Density-
INDEPENDENT
population controls
 Affect
population size
regardless of density
 Floods, fires, freezes,
hurricanes,
tornadoes, pollution,
habitat destruction,
pest control
Density-DEPENDENT
population controls
 Greater
effect with higher
density
 Competition, predation,
parasitism, and infectious
disease
 EX: Black Plague in Europe
& Citrus canker
Stable
 Size
population size
fluctuates only slightly above and
below carrying capacity
 Ex: species found in rain forests
Irruptive
 Short
period of explosive growth
 Followed by a crash
 Short-lived, rapid reproducers
 Ex: seasonal bugs
Cyclic
 Have
fluctuations
periods of up and down over a
longer amount of time
 Lemmings 3-4 year cycles
 Lynx and snowshoe hares 10 year
cycles
Irregular
 No
patterns
distinct pattern
 Not really understood why
Only
1 organism needed
Offspring are exact genetic clones
Usually smaller, simpler, singlecelled organisms
Budding, binary fission
97%
of organisms
Need 2 organisms
Sex cells (gametes) combine to
create one new, genetically unique
organism with DNA from both
parents
Men
don’t give birth. Women must
produce 2 kids to replace both
parents.
Increased chance of genetic defects
during meiosis
Courtship & mating rituals can be
time consuming and dangerous
Genetic
diversity is an advantage
when environments change
Males can gather food and protect
the women and children
2
types
Depends on where you find them on
the S-shaped population curve
Basic characteristics of reproduction
Have
capacity for high-rate of pop
increase (r)
Reproduce early
Make lots of eggs/ have lots of
babies
Little to no parental care
Produce so many to ensure some
survive
Ex:
bugs, algae, bacteria,rodents
Tend to be opportunists
Able to take over after a
disturbance
Can easily crash
Reproduce
later in life
Few babies that develop inside mom
Live longer
Born large, develop slowly
Parental care until they reach
reproductive age
Called
K-selected because they do
well in competition near their
carrying capacity
Typically follow logistic growth
Prone to extinction 
Most mammals, birds of prey, and
large/ long lived plants
Individuals
tend to have different
life expectancies
Can show this on a survivorship
curve
100
Percentage surviving
(log scale)
Late Loss
10
1
0
Early Loss
0.01
Age
Percentage surviving
(log scale)
100
10
1
0
Early Loss:
Survivorship is low early
in life, lots of babies die,
only a few adults age and
make it through adulthood
0.01
Age
Percentage surviving
(log scale)
100
10
Constant Loss: constant
death rate among all ages
Ex: song birds
1
0
0.01
Age
Percentage surviving
(log scale)
100
10
1
Late Loss:
High survivorship to
a certain age then
very high mortality
0
0.01
Age
Founder
 Genetic
effect:
diversity is limited when a few
individuals colonize a new habitat
 Geographically isolated from old pop
Demographic
 Only
bottleneck:
a few individuals survive a
catastrophic disturbance like a
hurricane or human disturbances
(hunting, deforestation)
Genetic
drift:
 Random
changes in gene frequencies
that allow certain individuals to breed
more which makes their genes more
dominant
Inbreeding:
 Individuals
in a very small pop breed
with each other
 Can increase frequency of defective
genes