Download Ecology: Animal Interactions

Ecology: Animal Interactions
Trophic Pyramids and Trophic
Webs
Review of Energy Principles
Photosynthesis – converts light energy into
chemical energy (glucose).
Respiration – converts chemical energy
(glucose) to chemical energy (ATP).
Laws of Thermodynamics
1st Law – conservation of energy, all energy must
be accounted for
2nd Law – order to disorder heat
What is Ecology?
study of the interaction between abiotic and biotic
components of……
How do non-photosynthetic organisms capture energy?
They eat!
What happens to some of the
energy that they acquire? What is
it turned into?
What do they eat?
Where does the energy in what
they eat come from?
The
Sun
Light Energy Fates
Reflectance
Absorption by
nonphotosynthetic
systems
Radiated back
to space
Absorption by
photosynthesis
Let’s follow the sun’s energy
Let’s just follow it through Photosynthesis
Step 1: light energy absorbed by photosynthesis
Step 2: photosynthetic process (light dependent reactions)
Step 3: energy is now in form of glucose and can be stored in
other carbohydrate forms (starch, cellulose, etc.)
• If glucose is eaten by an animal it can remain as glucose or
stored as either glycogen or chitin
Light energy
Carbon
dioxide
Water
Photosynthesis
Glucose
Oxygen
gas
Terrestrial Food Chain (Step 4)
Aquatic Food Chain (Step 4)
Direction of Energy Flow
Energy Pyramid
Since the heat
is no longer
useful, at each
step, the
amount of
useful energy
from our
original burst
of sunlight is
reduced.
Energy
Energy passes through biological systems
Energy enters the system via photosynthesis
Energy passes through the biological system
through trophic levels via metabolism
(cellular respiration)
Energy leaves the biological system in the
form of heat.
Energy does not flow linearly - Food Webs
Interactions Between Organisms
Interaction type
Interspecific
interactions are
interactions
between species.
Intraspecific
interactions are
interactions
within the same
species.
Effect on
Actor
Effect on
Target
1. Herbivory
Beneficial
Harmful
2. Predation
Beneficial
Harmful
Harmful
Harmful
Parasitism
Beneficial
Harmful
Commensalism
Beneficial
Neutral
Mutualism
Beneficial
Beneficial
3. Competition
4. Symbiosis
1. Herbivory
Herbivory - the interaction is beneficial to the
actor but harmful on the target
Herbivore
Omnivore
2. Predation
Predation- the interaction is beneficial to the actor
but harmful on the target
Carnivore
Omnivore
Predation effect on species diversity within a community ecosystem
With Pisaster
(control)
Without
Pisaster
Competition
The effect on the actor is harmful and the
effect on the target is harmful
High
tide
Chthamalus
Balanus
Ocean
Low
tide
Chthamalus can live lower on the shore but doesn’t because it is
competitively displaced by Balanus. Higher mortality of juvenilles as well.
Symbiotic Interactions
Parasitism- effect on the actor is beneficial and
harmful on the target.
Commensalism
The effect on the actor is beneficial and the effect on the
target is neutral.
The Cattle Egret (Bubulcus ibis) forages in pastures and fields among livestock
such as cattle and horses, feeding on the insects stirred up by the movement of
the grazing animals. The egrets benefit from the arrangement, but the livestock,
generally, do not.
Mutualism
The effect on the actor is beneficial and the effect on the
target is beneficial
Bird benefits by getting food while buffalo benefits from removal
of potential parasites.
You should be able to:
Follow energy from the sun through a food chain or
food web, and identify the conversions that happen.
Use a food web or food chain to identify the trophic
relationships of represented organisms.
Identify the immediate source of energy for an organism
and the original source of energy for all organisms.
Explain the role of detritivores in a food chain or food
web.
Explain why the energy pyramid is shaped the way it is.
Explain/identify how different types of interactions
affect both of the organisms involved.