Download File - SCIENTIST CINDY

Two idealized patterns of population growth:
1.
2.
Exponential (or “geometric” for discrete version)
Logistic (s-shaped)
Exponential Growth Model

Plenty of resources
Logistic Growth Model When a population is introduced to a new environment, it will often
display Exponential Growth. •After some time, this will change to a logistic growth model
when the population approaches carrying capacity. S shaped.
•Carrying capacity (the limitations of that environment)
Limiting factors that contribute to the logistical growth model are …
1.
2.
3.
4.
5.
6.
7.
8.
9.
Predation
Parasites
Food sources
Illness
Change in environment
Predation
Territory
Illness
Change in environment
Intraspecific competition – when members of the same species compete for limited
resources. This leads to a reduction in fitness for both individuals.
10.
Interspecific competition - when members of different species compete for a
shared resource.
I.
Natural Selection
A.
Definition – natural selection is the phenomenon that genetic or behavioral traits
that improve the rate of survival and having offspring, will persist in the population.
Likewise, that genetic or behavioral traits that reduce the rate of survival or having
offspring, will decrease or die out.
II.
A.
The Survivorship curves
There are 3 types of survivorship curves
1.
Type I survivorship curve
a)
Most of the individuals of that species will survive until they
reach “old age”
b)
2.
Examples
(1)
Humans
(2)
Large mammals
Type II survivorship curve
a)
For a Species that exhibits a type Ii survivorship curve – the
survivorship of that species remains relatively constant over the
lifespan.
b)
Examples:
(1)
Hydra
3.
Type III survivorship curve
a)
Live fast / die young – fish are example
B.
Competition exists when there is a limited supply of one or more resources (such as
food, mates, water, and territory).
III.
2 possible outcomes of Competition
1.
Competitive Exclusion –
a)
The winner (more successful competitor) gets all the resources
and the other gets none.
b)
The loser (less successful competitor) must find alternative
resources, which sometimes means relocating.
2.
IV.
c)
Takes a lot of biological energy
d)
Increases stress
Resource Partitioning
a)
Resources are shared between the competitors.
b)
Saves biological energy
c)
It is a compromise
Predators and prey interaction –
A.
Predators and prey are in a constant battle to gain an advantage that will help
them survive.
B.
Whenever a predator develops an advantage that helps them acquire prey, this
CAUSES the prey to adapt and find a way to avoid this new method of predation.
C.
The organisms that most effectively adapt to and avoid predation will survive and
reproduce.
D.
It works in the opposite direction too. When prey organisms develop an effective
defense against predation, predators must adapt to the change and find a way around the
defense, or find a new organism to prey on.
E.
Predators that don't adapt and can't capture prey will starve to death.
F.
V.
Predators and prey evolve in response to interactions with each other.
Coevolution
A.
Definition - occurs when different species evolve together creating long-standing
relationships that persists over many generations.
VI.
SYMBIOSIS
A.
Symbiosis results from coevolution of beneficial behaviors between different
species.
B.
In symbiosis, individuals of one species usually live in or on or around the individuals
of another species.
C.
At least one of the species—and sometimes both—uses its partner’s resources.
D.
The partners of a symbiotic relationship, may benefit from, be unaffected by, or be
harmed by the relationship. Each of these types of symbiosis have special names.
E.
There are 3 types of symbiotic relationships
1.
Mutualism - Both species benefit
2.
Commensalism - One species benefits, but the other is not helped or
harmed
3.
VII.
A.
Parasitism - One species benefits, but the other is harmed
Mutualistic Symbiotic Relationships
The Sea Anemone and the Clown Fish
1.
SEA ANEMONES
a)
Are predators that attach themselves to rocks or coral
b)
They are immobile
c)
Eat fish by stinging it with its tentacles as it swims by
d)
These tentacles will shoot out a long poisonous thread.
e)
The toxins in this thread paralyze the prey.
2.
CLOWNFISH
a)
They are one of the only species that can survive the deadly
sting of the Sea Anemone.
b)
By making the anemone their home, clownfish become immune
to its sting. These fish will gently touch every part of their bodies to the
anemone’s tentacles until it no longer affects them. A layer of mucus
then forms on the clownfish’s body to prevent it from getting stung
again.
3.
IN THE MUTUALISTIC SYMBIOTIC RELATIONSHIP BETWEEN THE SEA
ANEMONE AND THE CLOWNFISH…
a)
A sea anemone makes an ideal home for a clownfish.
b)
The Sea anemone’s poisonous tentacles provide protection to
the clownfish by warding off predators.
c)
The clownfish makes its meals from the anemone’s leftovers and
feces!
d)
A clownfish can help an anemone catch its prey by luring other
fish toward over so that the anemone can catch
them.
e)
Clownfish also eat any dead tentacles keeping the anemone and
the area around it clean.
VIII.
A.
Parasitic Symbiotic Relationships
The Tongue-Eating Louse (Cymothoa exigua) and Fish
1.
The tongue-eating louse is a parasite that replaces the tongue of its victims.
2.
The tongue eating louse enters its victim through the gills.
3.
The tongue-eating louse uses its front claws to latch onto the fish’s tongue
and suck out the blood. This eventually causes the tongue to die and drop off.
4.
After the tongue falls off, the louse attaches itself to the left-over tongue
stub, and effectively replaces the tongue.
5.
B.
Each infested fish usually has 5 or 6 of these in their mouth
Zombie Ants – Fungi Parasitic Relationship
1.
Zombie ants are ants that have been infected by parasitic fungus known to
manipulate the brains of ants turning them into ‘slaves’.
2.
The fungus recognizes the brains of specific ant species, and releases its
mind-controlling chemical cocktail only when in its preferred host.
3.
"Behavioral manipulation” is very rare in nature and it only occurs when
there's a very close coevolution between pathogen and host.
4.
The zombie ant fungi need ants to complete their life cycle. The fungus
reproduction strategy is completely dependent on the infection and hostile
takeover of the ant!
5.
The infection occurs when the ant is exposed to fungal spores while
foraging. The fungus infects the insect and quickly spreads throughout its body.
6.
Once inside the host ant, the fungus in the ant's head release chemicals
that CONTROL the insect's central nervous system.
7.
The fungus forces the ant to climb up vegetation and clamp down onto a
leaf or twig before killing its hapless drone.
8.
It then grows a spore-releasing stalk out of the back of the victim's head to
infect more ants on the ground below.
C.
The Botfly Parasite
1.
Botflies have a unique way of reproducing. They require a human or
mammal host in order to complete their life cycle.
2.
Adult female botflies lay their eggs on blood-sucking insects, such as
mosquitoes or tick.
3.
When the blood-sucking insect lands on a human, it drops the eggs on its
victim.
4.
The warm body of the human triggers the bot fly to hatch from its egg.
5.
The larvae (bot fly babies) may travel down hair follicles or through bite
wounds and burrow into the mammal's skin.
6.
The larvae growing in the skin drop from the mammal host after a period of
30 days.
IX.
Predator/Prey Interactions
A.
A predator is an animal that hunts and kills other animals for food.
B.
Prey is a term used to describe animals that are hunted and killed by predators.
C.
We can also think of herbivores as predators of plants and plants as prey of
herbivores.
D.
Predation is a strong, selective pressure that drives prey organisms to find ways to
avoid being eaten.
E.
Prey organisms that are difficult to find, catch or consume are the ones that will
survive and reproduce.
X.
A.
Prey Strategies to Avoid Predation
Chemical defenses
1.
Common among animal prey.
2.
The South American poison arrow frog has poison glands in its skin.
3.
Some insects developed the ability to tolerate milkweed toxins. This allows
the insect to be able to eat milkweeds without being poisoned. The insects then
use this to their advantage by eating a bunch of milkweed which makes them
poisonous to predators.
4.
Horned lizards are able to squirt a stream of blood from the corners of their
eyes as a defense against predators.
a)
This blood squirt can reach a distance of up to 5 feet!
b)
They do this by restricting the blood flow leaving the head,
thereby increasing blood pressure and rupturing tiny vessels around the
eyelids.
c)
This not only confuses predators, but also the blood tastes foul
to canine and feline predators.
B.
Camouflage
1.
Some animals blend into their surroundings to hide from predators.
Camouflage, also called cryptic coloration, is a defense or tactic that organisms use
to disguise their appearance, usually to blend in with their surroundings.
2.
Organisms use camouflage to mask their location, identity, and movement.
3.
This allows prey to avoid predators, and for predators to sneak up on prey
4.
The animal’s behavior often enhances such cryptic coloration. In other
words, they sometime will not only look like something else, but act like something
else.
5.
C.
The octopus has the most advanced camouflage capabilities.
Safety in numbers –
1.
Some animals live in groups—a herd of antelope, colony of honeybees,
school of anchovies, or flock of pigeons. This social behavior decreases the
likelihood of a predator catching one of them unaware; the group has many eyes,
ears, and noses watching, listening, and smelling for predators.
D.
Running away.
1.
Gazelle, deer, small mammals and lizards often rely on their speed and
quickness to escape predators, and many birds rely on flight as their primary
defensive strategy.
E.
Fighting back –
1.
Physical defense - Some organisms, like armadillos, tortoises, porcupines
and thorny plants, use armor, quills and thorns to defend themselves against
predators.
2.
Wolverine Frog breaks its own bones to produce claws that puncture their
way out of the frog’s toe pads when it is threatened.
XI.
PREDATORS
XII.
Niches
A.
A niche is the role that an organism plays in nature.
B.
It is extremely unusual to find two organisms with the same exact niche
C.
An ideal niche that would exist in the absence of competition from other species is
called a species' fundamental niche.
D.
However, most organisms are generally forced to play a more limited role thanks to
competition. The actual niche that a species fills in the face of interspecific competition is
called its realized niche.
XIII.
Factors that become more limiting as the population increases are called densitydependent factors. Some examples of density-dependent factors are
A.
The amounts of habitat, food, water and shelter that are available.
B.
In most species, reproductive rate is also density-dependent.
XIV.
Factors are not affected by population size are called density-independent factors.
One example of a density-independent factor is
A.
XV.
Climate changes.
Intraspecific Competition
A.
Intraspecific Competition is competition for resources among 2 (or more) individuals
of the same species.
B.
When resources are limited, and this forces members of the same species to
compete for them, which is called intraspecific competition. The resources may include
food, shelter, water, and mates.
C.
Examples of intraspecific competition
1.
Marking territory –
a)
Many wild canine and feline species mark their territories with
scent.
2.
Ornamental features –
a)
Male peacocks display beautiful plumage to attract females.
Male deer fight each other for mates with their large antlers - the larger
set of antlers usually wins this competition.