Unit 4: Ecosystems Flashcards

Questions and Answers

What is the 10% rule?

The 10% rule states that only 10% of the available energy is transferred to the next level of the food chain. Most of the 90% is lost as heat.

How does the 10% rule relate to the number of organisms of each trophic level?

As the trophic level gets higher, the number of organisms decreases due to the amount of energy being transferred.

If the producers have 1000 calories, how many make it to the secondary consumer?

10 calories.

What happens to the other 90% of the energy?

The other 90% of energy is lost as heat. Signup and view all the answers

What are the trophic levels? Give an example of 2 organisms in each trophic level.

Trophic levels are producers (level 1), primary consumers (level 2), secondary consumers (level 3), and tertiary consumers (level 4). Examples: Producers - wheat, grass; Primary consumers - mouse, deer; Secondary consumers - snake, eagle; Tertiary consumers - wolf, owl. Signup and view all the answers

What is the main source of energy for primary producers?

The energy for producers comes from the sun. Signup and view all the answers

What is the difference between a food chain and a food web?

A food chain shows how energy flows from one organism to another; a food web is a community of organisms with multiple interconnected food chains. Signup and view all the answers

What is a keystone species? Give an example and explain why they are important.

Keystone species are those that significantly influence the survival of many other species in an ecosystem. An example is a squid. Signup and view all the answers

Explain the first law of thermodynamics.

Energy is not created or destroyed, it is only transferred from one form to another. Signup and view all the answers

Explain the second law of thermodynamics.

Energy decreases in quality as it transfers higher up the trophic pyramid. Signup and view all the answers

Describe homeostasis.

Homeostasis is the ability to maintain a stable environment despite external changes. Signup and view all the answers

What is the difference between abiotic and biotic? Give 2 examples of each.

Abiotic is non-living, while biotic is living. Examples: Biotic - organisms, plants; Abiotic - water, rocks. Signup and view all the answers

How do abiotic factors support biotic factors? Give one example.

Abiotic factors provide organisms with necessary resources. For instance, insufficient sunlight can hinder plant growth. Signup and view all the answers

How do biotic factors support abiotic factors? Give one example.

Biotic factors can affect the geography and resources around them, such as too many deer near a riverbank decreasing water clarity. Signup and view all the answers

Explain 3 methods in which humans have managed ecosystems.

Humans manage ecosystems by reintroducing species, controlling populations, and managing resources. Signup and view all the answers

Study Notes

10% Rule

Only 10% of available energy transfers to the next trophic level; 90% is lost as heat.

Relationship to Trophic Levels

Higher trophic levels have fewer organisms as energy decreases with each level, resulting in more autotrophs (producers) compared to heterotrophs (consumers).

Energy Transfer Example

If producers have 1000 calories, secondary consumers receive only 10 calories due to the 10% energy transfer rule.

Energy Loss

90% of energy at each trophic level is lost as heat, highlighting inefficiency in energy transfer.

Trophic Levels and Organism Examples

Trophic Levels:
- Producers (level 1): wheat, grass
- Primary Consumers (level 2): mouse, deer
- Secondary Consumers (level 3): snake, eagle
- Tertiary Consumers (level 4): wolf, owl

Primary Producers’ Energy Source

Primary producers derive energy from the sun through photosynthesis, supplying energy for primary consumers.

Food Chain vs. Food Web

A food chain illustrates direct energy flow between organisms, while a food web represents multiple interlinked food chains in a community.

Keystone Species

Keystone species, like squid, significantly affect ecosystem balance by influencing other species’ survival and population dynamics.

First Law of Thermodynamics

Energy is neither created nor destroyed; it merely changes form during transfer.

Second Law of Thermodynamics

Energy quality diminishes as it moves up the trophic pyramid, resulting in lower usable energy at higher levels.

Homeostasis

Homeostasis refers to an organism's ability to maintain stable internal conditions despite external environmental changes.

Abiotic vs. Biotic Factors

Abiotic factors: non-living components (e.g., water, rocks).
Biotic factors: living organisms (e.g., plants, animals).

Support of Biotic by Abiotic Factors

Abiotic factors, such as sunlight, can limit plant growth; insufficient resources lead to environmental challenges.

Support of Abiotic by Biotic Factors

Biotic factors can alter their surroundings; for example, deer populations affect water clarity by grazing near banks.

Human Ecosystem Management

Human interventions include reintroducing endangered species, managing wildlife populations, and influencing resource availability.

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Description

Explore the concept of ecosystems with these flashcards focused on the 10% rule and its implications on energy transfer in food chains. Understand how this principle affects the number of organisms at each trophic level. Perfect for students studying ecology and environmental science.