D: Biology = Changes in Living Systems 1.3 The Web of Life Flashcards
What is an ecosystem?
An ecological system where key parts are organized in specific ways to function sustainably.
Includes interactions between organisms and their physical environment.
What is the initial source of energy for organisms in the prairie grassland ecosystem?
Energy from the Sun captured by grasses and wildflowers through photosynthesis.
What are producers?
Organisms that convert light energy and store it in the chemical bonds of organic molecules.
Includes green plants, algae, and phytoplankton.
What process do producers use to synthesize sugars and organic compounds?
Photosynthesis.
What are consumers?
Organisms that rely on other organisms as a source of energy.
What are primary consumers or herbivores?
Organisms that eat green plants, algae, or phytoplankton.
Fill in the blank: An organism that uses light energy to synthesize sugars and other organic compounds through the process of _______ is called a producer.
photosynthesis
Fill in the blank: An organism that uses other organisms as a source of energy is called a _______.
consumer
True or False: Herbivores are a type of primary consumer.
True
What types of organisms are included in the category of producers?
- Green plants
- Algae
- Phytoplankton
What role do primary consumers play in an ecosystem?
They eat producers such as green plants and algae.
What are grasshoppers classified as in the prairie grassland ecosystem?
Herbivores
Grasshoppers eat the leaves of grasses and other plants.
What term is used for organisms that eat herbivores?
Secondary consumers
Yellow warblers eat grasshoppers.
What are peregrine falcons classified as in the food chain?
Tertiary consumers
They eat secondary consumers like yellow warblers.
What classification applies to yellow warblers and peregrine falcons due to their eating habits?
Carnivores
They kill and eat other animals.
What are animals called that eat both plants and animals?
Omnivores
Example: Sparrows eat seeds and insects.
What term describes skunks when they eat a variety of foods including insects, bird eggs, and berries?
Omnivores
Skunks also eat mice.
What role do skunks sometimes play when they consume the remains of dead animals?
Scavengers
They feed on meat from animals that died from various causes.
What is a scavenger?
A larger animal that feeds on dead and decaying animals that it did not kill itself
This term is usually reserved for larger organisms.
What are decomposers responsible for in an ecosystem?
Breaking down complex organic molecules into simpler molecules
They return organic material to inorganic material.
Why are decomposers critical to the ecosystem?
They provide essential inorganic compounds required by producers
Decomposers act on all dead plant and animal matter.
Fill in the blank: An organism that eats both plants and animals is called an _______.
Omnivore
True or False: All animals fit neatly into the categories of herbivores, carnivores, and omnivores.
False
Some animals are opportunists and eat a wide variety of foods.
What is the definition of a tertiary consumer?
An organism that eats secondary consumers
Example: Peregrine falcons.
What is the definition of a secondary consumer?
An organism that eats herbivores
Example: Yellow warblers.
What do decomposers do with organic material?
They return it to inorganic material
This process is essential for the ecosystem.
What is the primary source of energy for a prairie grassland ecosystem?
Light energy from the Sun
What type of molecules store energy in a prairie grassland ecosystem?
Large organic molecules such as sugars, starches, fats, and proteins
What are the organisms that feed on plants in an ecosystem called?
Herbivores
What is each step in the energy pathway through an ecosystem called?
Trophic level
What does the term ‘trophic’ mean?
To nourish
What comprises the third trophic level?
Carnivores that eat herbivores
What is the fourth trophic level made up of?
Carnivores that eat other carnivores
Where can omnivores and scavengers be placed in the trophic levels?
At the second, third, or fourth trophic levels depending on their diet
What is the first trophic level in the energy pyramid?
Producers
What is the second trophic level in the energy pyramid?
Primary Consumers
What is the third trophic level in the energy pyramid?
Secondary Consumers
What is the fourth trophic level in the energy pyramid?
Tertiary Consumers
Fill in the blank: The division of species within an ecosystem based on its energy source is called a _______.
trophic level
What approximate percentage of original solar energy is available at the first trophic level?
0.001%
What approximate percentage of original solar energy is available at the second trophic level?
0.01%
What approximate percentage of original solar energy is available at the third trophic level?
0.1%
What shape is used in the ‘Energy Pyramid’ diagram?
Pyramid
What percentage of sunlight energy can producers store?
About 1%
What happens to some of the solar energy that reaches Earth?
It is reflected back into space or evaporates water
What is the role of energy in the life processes of producers?
It is used for life processes
How much of the sunlight energy made available to plants can herbivores store?
About 0.1%
What do herbivores need energy for?
Chewing food, moving, reproducing, completing life functions
What happens to energy used by organisms for life functions?
It leaves the ecosystem as heat
What percentage of energy is passed on to the next trophic level?
About 10%
True or False: Energy is recycled in an ecosystem.
False
Fill in the blank: Energy enters the ecosystem in _______ form.
solar-energy
How is energy ultimately passed back into the environment?
As heat
What shape is used in the ‘Energy Pyramid’ diagram?
Pyramid
What percentage of sunlight energy can producers store?
About 1%
What happens to some of the solar energy that reaches Earth?
It is reflected back into space or evaporates water
What is the role of energy in the life processes of producers?
It is used for life processes
How much of the sunlight energy made available to plants can herbivores store?
About 0.1%
What do herbivores need energy for?
Chewing food, moving, reproducing, completing life functions
What happens to energy used by organisms for life functions?
It leaves the ecosystem as heat
What percentage of energy is passed on to the next trophic level?
About 10%
True or False: Energy is recycled in an ecosystem.
False
Fill in the blank: Energy enters the ecosystem in _______ form.
solar-energy
How is energy ultimately passed back into the environment?
As heat
What does the pyramid of numbers describe?
Trophic levels
The pyramid of numbers illustrates the population sizes of different trophic levels in an ecosystem.
Why must the pyramid of numbers be used cautiously?
Because the size of individual organisms matters
For example, a falcon weighs significantly more than a grasshopper, which affects the interpretation of population ratios.
What is the dry mass of a falcon approximately?
500 g
This is an average measurement and can vary among different species of falcons.
What is the dry mass of a grasshopper approximately?
1.5 g
This value can vary based on the species and size of the grasshopper.
What is the ratio of grasshoppers to falcons in the example given?
100,000 grasshoppers to 2 falcons
This ratio emphasizes the large number of producers required to support a small number of top predators.
How many producers are needed to support the two top predators?
More than a million producers
This highlights the fragility of the ecosystem for top predators like falcons.
What does the small number of falcons indicate about their situation?
It indicates a fragile ecosystem
The small population must cover a large geographic area to find enough producers.
True or False: The trends shown on the ‘Pyramid of Numbers’ are always accurate without considering mass.
False
The trends can be misleading if the mass of organisms is not taken into account.
Fill in the blank: The pyramid of numbers illustrates the relationship between _______ and trophic levels.
[population sizes]
This reflects how many organisms exist at each level of the food chain.
What are ecological pyramids used for?
Useful organizers of ecological information
Ecological pyramids do not provide detailed information about interactions between populations.
What is the starting point of a food chain?
Producers
Food chains show how energy is passed along by one organism feeding on another.
How are food chains constructed in aquatic ecosystems?
They also start with producers
Similar to terrestrial food chains.
What is the strength of using a food chain to represent energy transfer?
It shows details of the feeding between trophic levels
This allows for understanding how energy moves through different levels.
What is a food web?
The interconnecting feeding relationships within an ecosystem
Food webs are formed from the overlapping and interconnecting food chains.
Define ‘food chain’.
The pathway along which food is transferred from one trophic level to the next
Illustrates the linear flow of energy through an ecosystem.
Define ‘food web’.
The interconnecting feeding relationships within an ecosystem
Illustrates the complex interactions among various food chains.
In a freshwater food chain, what is the primary consumer?
Mosquito larvae
They feed on producers like algae.
In a prairie grassland food chain, what is the secondary consumer?
Yellow warbler
They feed on primary consumers like grasshoppers.
What is the tertiary consumer in the freshwater food chain?
Northern pike
They are at the top of the food chain, preying on secondary consumers.
What is the tertiary consumer in the prairie grassland food chain?
Peregrine falcon
They are apex predators in this ecosystem.
What do producers, such as plants, do?
Producers make nutrients that can be used by other living organisms
Producers are the foundation of food chains and webs.
What is a food chain?
A simple model that shows how energy and matter move from producers to consumers and decomposers
Food chains illustrate direct feeding relationships.
What do food webs represent?
Many interconnected food chains and illustrate pathways in which energy and matter are exchanged in an ecosystem
Food webs provide a more complex picture of ecosystem interactions.
How is matter recycled in an ecosystem?
Matter is recycled through the trophic levels
This recycling is essential for maintaining ecological balance.
In what direction does energy flow through the trophic levels?
In a single direction
Energy flows from producers to consumers to decomposers.
What is a key characteristic of energy transfer in an ecosystem?
Energy transfer is inefficient
A significant amount of energy is lost as heat during transfer.
What are ecological pyramids used for?
To express quantitative data in a visual manner
They help in understanding energy distribution and population dynamics.
What are the three types of ecological pyramids?
Energy, numbers, and biomass
Each type provides different insights into ecological structure.
What do producers, such as plants, do?
Producers make nutrients that can be used by other living organisms
Producers are the foundation of food chains and webs.
What is a food chain?
A simple model that shows how energy and matter move from producers to consumers and decomposers
Food chains illustrate direct feeding relationships.
What do food webs represent?
Many interconnected food chains and illustrate pathways in which energy and matter are exchanged in an ecosystem
Food webs provide a more complex picture of ecosystem interactions.
How is matter recycled in an ecosystem?
Matter is recycled through the trophic levels
This recycling is essential for maintaining ecological balance.
In what direction does energy flow through the trophic levels?
In a single direction
Energy flows from producers to consumers to decomposers.
What is a key characteristic of energy transfer in an ecosystem?
Energy transfer is inefficient
A significant amount of energy is lost as heat during transfer.
What are ecological pyramids used for?
To express quantitative data in a visual manner
They help in understanding energy distribution and population dynamics.
What are the three types of ecological pyramids?
Energy, numbers, and biomass
Each type provides different insights into ecological structure.
