Ecology - Energy Transfer and Flow Notes

Energy Transfer and Flow

Energy Transfer

Producers (Autotrophs)

• Energy originates from the sun.
• Producers, also known as autotrophs, are organisms that create energy-rich compounds like glucose through photosynthesis.
• Examples of producers include plants, certain bacteria species, and algae.

Energy From the Sun

• Photosynthesis is the process of converting carbon dioxide (CO2) and water (H2O) into sugars (glucose) and oxygen using sunlight.
• The basic photosynthesis equation involves light energy, carbon dioxide, and water, resulting in oxygen.

Life Without Light

• Some organisms inhabit deep-sea hydrothermal vents.
• Continental shelf average width = 50 miles (varies from a few to 900 miles).
• Continental slope average depth 12,500 feet.

Life Without Light

• Chemosynthesis uses chemical energy to produce carbohydrates from carbon dioxide (CO_2), hydrogen sulfide, and oxygen.
• Chemosynthetic bacteria prevent oceans from becoming toxic.
• They create a microbial mat.
• Grazers like snails, limpets, and scale worms eat the mat, and predators consume the grazers.

Consumers (Heterotrophs)

• Consumers, or heterotrophs, cannot produce their own food.
• They rely on other organisms for energy and nutrients.

Types of Consumers

• Carnivores kill and eat other animals (e.g., snakes, tigers, coyotes, hawks).
• Scavengers consume carcasses (e.g., turkey vulture).

Types of Consumers

• Herbivores eat plants (e.g., cows, caterpillars, deer).
• Omnivores consume both plants and animals (e.g., humans, bears, pigs).

Other Types of Consumers

• Decomposers chemically break down organic matter (dead plants and animals) and feed on it.
• They produce detritus, which consists of small pieces of decaying plant and animal remains.
• Decomposers play an important role in nutrient cycling back into the soil, water, and air.
• Examples of decomposers are bacteria and fungi.

Other Types of Consumers

• Decomposers produce detritus, which consists of small pieces of decaying plant and animal remains.
• Detritivores feed on detritus (remains of dead organic material).
• Examples of detritivores are earthworms, mites, and snails.

Detritivores in Aquatic Food Webs

• Often called "bottom-feeders."
• Examples include crustaceans like crabs and lobsters, and echinoderms like sea stars or sea cucumbers.

Energy

• Sunlight is the primary source of energy for most living things.
• Producers (Plants) use sunlight to make food.
• Consumers like the black-tailed prairie dog (herbivore) eat seeds and grass.
• Other consumers like coyotes (carnivore), hawks and badgers eat prairie dogs.

Energy

• A turkey vulture (scavenger) may consume leftovers.
• Decomposers like bacteria and fungi break down any prairie dog remains.

Energy Flow

Food Chain

• A food chain is a diagram illustrating how energy flows from one organism to another.
• Primary producer → Herbivore → Carnivore.
• Example: Algae → Flagfish → Largemouth bass → Anhinga → Alligator.

Food Web

• A food web is a diagram that shows the feeding interactions between organisms in an ecosystem.
• It illustrates the transfer of energy within an ecosystem when one organism consumes another.

Food Chains Within Food Webs

• Each path through a food web is a food chain.
• A food web links all food chains in an ecosystem together.

Food Chains Within Food Webs

• Example: Grassland Ecosystem
• Several food chains can be identified, involving grasses, grains, carrots, grasshoppers, mice, rabbits, birds, owls, and foxes.

Keystone Species

• A keystone species' population change causes dramatic changes in the structure of a community and ecosystem.
• Examples: sea otters, sharks, elephants.

Keystone Species

Why do sharks matter?