Chapter 6 - Objectives

1. List the productivity significance of “Light.” Does it matter if you’re not a plant?

2. Determine to what extent plants filter light from the heavens

3. Determine to what extent water filters light in the aquatic system

Chapter 6 - Objectives

4. List the adaptive mechanisms plants and animals used in promoting or discouraging energy transfer.

5. Explain diurnal rhythms (Circadian) and how they may effect energy transfer.

Energy (Food)

Basic organism essential elements:

Carbon

Nitrogen

Hydrogen 93%

Oxygen

Phosphorus

Plus a bunch of others - 7%

Energy (Food)

Plus----------

Energy source to build up compounds that can be used for growth

1. Radiant energy (most of the energy)

Photosynthesis

2. Chemical energy (deep sea bacteria)

Chemosynthesis

Fig. 6.2

• Primary Productivity is the production of organic material through photosynthesis.

• Basic Equation:

6 CO2 + 6 H2O = C6H12O6 + O2

Primary Productivity

• Primary Productivity is the production of organic material through photosynthesis.

• Basic Equation:

Light Energy

6 CO2 + 6 H2O = C6H12O6 + O2

Primary Productivity

Light

BUT!!!!

It’s not just quantity,

It’s also quality----

GR -->XR-->UV-->VISIBLE-->IR--->MICRO--->RADIO

shortest----------------------------------------------------->longest

Light

BUT!!!!

It’s not just quantity,

It’s also quality----

GR -->XR-->UV-->VISIBLE-->IR--->MICRO--->RADIO

shortest----------------------------------------------------->longest 250-315Ozone Depletion (UV-B)

Visible Light

Visible spectrum approximations: 400-750 nm

1) Red 750

2) Orange

3) Yellow

4) Green

5) Blue

6) Indigo

7) Violet 400

Visible Light/Adaptations

Visible spectrum approximations

1) Red

2) Orange

3) Yellow

4) Green

5) Blue - - Aquatic Plants use most!!!

6) Indigo

7) Violet

Plant Light - General

The wavelengths used in photosynthesis:

Photosynthetically Active Radiation

PAR

Fig. 6.3

Visible Light/Aquatics

Extinction Coefficient:

Attenuation of light is exponential through the water column. Both intensity and quality can change quickly.

Iz = Ioe-kz

Visible Light/Quality

Angle of Incidence: Altitude of the sun

• Morning/Evening - Longer path through the atmosphere, Blue’s Absorbed, Red’s Prevalent

Plant Light Adaptations

1. Morphological changes e.g., different pigments, different levels of chloroplasts, based on available light

2. Movement of plants to in response to light path - Phototaxis - e.g., Leaves and algae

3. Diurnal duration e.g., function of latitude and season

Animals and Light

Light----Does it matter to animals?

• Not directly for organic production

• But it may affect feeding and behavior

Animals and Light

• Many visual feeders - e.g., walleye

Crepuscular: Of, pertaining to, or resembling

twilight!!!!

Animals and Light

Defense - e.g., schooling of fish during day

Break up school at night!!

Animals and Light

Most mammals are nocturnal

e.g., raccoons, deer, bears

Others: owls

Eye adaptation - More rods than cones (color)

No seein’, No eatin’

Animals and Light

Light - Plants and Animals

Organisms respond to variations in quality and quantity of light - Adaptations in morphology, behavior, physiology, metabolic processes.

The Sun Sets on this Section!

Circadian Rhythms:

• Activities keyed to daylight (darkness)

• Daylight changes over year

• Activities change over the year

• Can trigger physiological processes and metabolic rates e.g., reproduction, flowering, migration, feeding cycles

Energy of organisms (Food)

Photosynthetic - produce food with radiant energy

Heterotrophic - obtain food by eating other organisms

Chemosynthetic - produce food from chemical energy

Energy of plants (Food)

Pho

tosy

nthe

tic

Rat

e

Increasing sunlight (photon flux density)

Isat

Pmax

Fig. 6.19

Functional Response: Three types

1. Type 1 Response

As prey increases the number of prey consumed increases proportionally until predators are satiated.

Energy of Animals

Functional Response: Type 1

Energy of Animals

# Prey Available

# Prey Consumed

Fig. 6.21

Functional Response: Type 1

Energy of Animals

# Prey Available

# Prey Consumed

Satiation

Fig. 6.21

Functional Response: Three types

2. Type 2 Response

As prey increases from low levels, the number of prey consumed increases rapidly. However, as prey density reaches higher levels, further increases in the number of prey consumed is slowed by the amount of time needed to “handle” (kill and eat) the prey

Energy of Animals

Functional Response: Type 2

Energy of Animals

# Prey Available

# Prey Consumed

Fig. 6.21

Functional Response: Three types

3. Type 3 Response

As a previously rare species increases, predators slowly increase their consumption of that prey at first, then rapidly increase their consumption with prey density, until limited by predator satiation or prey handling time

Energy of Animals

Functional Response: Type 3

Energy of Animals

# Prey Available

# Prey Consumed

Fig. 6.21

Food Choice

1. Eat/uptake items that will produce energy for them

Standardneo-tropicalmigrant

GreyDogwood

Herbivores and Carnivores

Optimum Foraging Theory:

Natural selection will favor those individuals within a population that are more effective at acquiring energy----------And, they do this to maximize or minimize some quantity

E.g., Bluegills and size of prey (Fig. 6.24)

Optimum Foraging Theory:

Bluegills

Fig. 6.24

Food Choice

2. Adaptations that allow predator to efficiently obtain nutrients and energy from prey species.

e.g., Herbivores digesting cellulose with the help of bacteria, fungi or protists that live in their digestive tract.

Food Choice

3. Prey species produce defenses that can be formidable.

• Chemicals - toxins and digestion-reducing substances

• Morphological defenses e.g., spines, camouflage, behavior, mimicry, size or number

NO defense is perfect or 100% sure!!!

Fig. 6.14

Fig. 6.16

Bluegills

Bluegills

Done with Chapter 6