A. The basic needs for survival do not vary
from animal to animal.
B. All organisms must breathe, have clean water
to drink, food to eat, and shelter for protect
from the elements.
C. Individuals do not depend on reproduction to
survive, but if we expect species to continue
some members of each species must reproduce.
D. Let review: What is a species?
1. A group of organisms that can mate and
produce a viable offspring capable of
producing their own offspring
2. The final step in taxonomy;
part of the scientific name.
E. Population- a group of individuals of the same
species living in the same place at the same
time.
1. Dogs, cats, humming birds, etc.
2. All students of AHS is a
population defined by
the school property.
F. Community –different populations of organisms
living together in a particular area.
1. Think for a moment of a local pond or creek
near your neighborhood. What three aquatic
organisms living in or near the pond can you
think of? ___________, ____________,_______
2. Celebration Station Park comes to mind for
me. The animals making up that pond
community include ducks, fish, algae and
us feeding them to name a few.
A. Habitat
1. Definition-the physical
environment a species needs to survive.
2. Provides:
a. A shelter to escape from predators and the
elements.
b. The space needed for reproducing
c. A place for containing all individuals in a
population
d. Includes the food a for hunting, gathering
or producing
e. Contains all the things needed and preferred
f. Sustains everything a species needs to survive
over time.
1. Appropriate temperature
2. Adequate dissolved oxygen
3. Cover or particular bottom substrates.
g. Changes in habitat results in
1. Adaptations to the changes (or die)
2. Movement to another suitable habitat
3. Examples: fire, flood or earthquakes
3. Specialists verses Generalists
a. Specialists greatly affected by change , may not
survive over time; rare or endangered species
b. Generalists survive a wide range of habitat
conditions
A. Definition -the function, position or role of a
species within an environment
B. It defines how a species fits into its environment
based on its way of getting food, the habitat it
needs and the role it performs in the community.
C. Let’s look at two different species and see how
they can live together in a Texas reservoir in
their own niche and survive.
The Gizzard Shad and the Largemouth Bass
A. In a perfect world there would always be
enough food to go around and our basic needs
for survival would be provided in abundance.
But what is perfect one minute can be gone the
next. The shortage of a resource in a community
starts competition among species.
B. Competition
1. Definition-the act of actively seeking after and
using an environmental resource (such as food)
in limited supply by two or more plants or
animals or kinds of plants or animals.
2. The impact of competitions may adversely affect
one or many individuals of a species.
3. When prey in a body of water such as a pond, is
pursued by two different species, their niches
overlap creating situations if food becomes
scarce.
C. Carrying capacity
1. Definition- an ecosystem’s resource limit; the
maximum number of individuals in a
population that the ecosystem can support.
2. Resources impacting a carrying capacity are
biotic and abiotic factors.
3. When resources are plentiful ( more than the
population can use), they are considered to be
“below the carrying capacity”.
a. Individuals grow and reproduce
b. Death occurs for normal reasons
4. If the population grows too rapidly and the
resources can not support the population, this is
referred to as “above the carrying capacity.”
a. Individuals may experience starvation,
disease, parasites, accidents, increased fishing
or predators.
b. Over time, numbers drop and the carrying
capacity returns to normal
5. Example:
Perch Numbers Over The Carrying Capacity
P
E
R
C
H
Perch Numbers Are Below The Carrying Capacity