Unit 4 Ecosystems: Biotic & Abiotic Factors

Unit 4 Ecosystems

• Ecosystem: The interaction between living organisms (biotic factors) and non-living things (abiotic factors) around them.

Biotic and Abiotic Factors

• Biotic Factors: Living things
  • Animals
  • Plants
  • Fungi
  • Bacteria
• Abiotic Factors: Non-living things
  • Sunlight
  • Water
  • Air
  • Temperature
  • Soil

4.1 The Sonoran Desert

• Description: A desert in Arizona known for its resilience, adaptation, and beauty. Characterized by a harsh environment with minimal rainfall.
• Harsh Environment: Deserts in Arizona pose challenges for both plants and animals.
• Saguaro Cacti: Slow-growing, over 100 years old, with wide-reaching roots for water absorption.
• Diverse Wildlife: Includes Gila woodpeckers, other birds nesting in cacti, and cactus wrens preferring teddy bear cholla for protection.
• Survival Strategies: Animals seek shade or cooler soil during hot days; kangaroo rats emerge at night to feed.
• Impact of Rainfall: Heavy rains transform the desert, triggering rapid plant flowering; insects pollinate flowers, bats feed on agave nectar.
• Seed Dispersal: Ants collect and store seeds, leading to potential germination and new plant growth.
• Interactions in the Sonoran Desert: Mutual dependency between animals and plants; interconnected ecosystem where each organism's actions impact others; symbiotic relationships ensuring ecosystem sustainability; delicate balance of nature maintaining health and diversity.

4.1 Interactions with Non-Living Environment

• Light: Bright sunlight facilitates photosynthesis.
• Temperature: Diurnal temperature variations influence animal behaviour, some species being nocturnal to avoid daytime heat.
• Soil: Rocks and soil serve minerals for plant growth and material for ground-nesting birds.
• Water: Essential for cellular survival; activates desert life and facilitates reproduction upon rainfall.
• Air: Supplies carbon dioxide for photosynthesis and oxygen for respiration.

4.1 The Desert Ecosystem

• Food Webs: All food chains in an ecosystem joined together representing multiple pathways through which energy flows.
• Food Chain: Shows how energy is transferred from one organism to another.
• Arrows: Indicate the direction of energy transfer.

4.1 Adaptations

• Ecology: The study of ecosystems.
• Habitat: The place where an organism lives.
• Adaptations: Features of an organism that help it live and survive in its habitat. Examples include specific adaptations like long eyelashes, thick fur, hump, slit-like nostrils, thick waxy skin, spines, large surface area to volume, and long roots.

4.1 Other Information

• Species Extinction: Destruction or alteration of habitats by humans can lead to population decreases or extinction; once a species is extinct, it cannot exist again. A million species of plants and animals were at risk of extinction in June 2019.
• Cacti Adaptations: Includes thick, fleshy stems for water storage, waxy coatings to prevent water loss, spines instead of leaves to reduce water loss, and extensive root systems for water absorption.
• Types of Organisms in the Food Web: Herbivores (eat plants), Carnivores (eat meat), Omnivores (eat plants and meat), Producers (create their own food), Consumers (get energy by eating others), Predator (kills and eats others), Prey (killed and eaten by others)

4.2 Different Ecosystems

• Examples: Mangrove forests, sea ice in the Arctic Ocean, and rice paddies. These are various ecosystems with specific characteristics.

4.3 Intruders in an Ecosystem

• Key Words: Eradication, Extinction, Native species, Invasive species.
• Invasive Species: Organisms introduced to an ecosystem they don't belong in. Can grow rapidly and aggressively, harming ecological balance, biodiversity, human health and potentially causing native species extinction.

4.4 Bioaccumulation

• Dichlorodiphenyltrichloroethane (DDT): An insecticide used in agriculture, but very harmful to many animals as it's toxic and persistent in the environment.
• Persistent Chemical: Remains in the environment for many years.
• Bioaccumulation: The gradual increase of a substance in an organism's body. This occurs when the substance cannot be broken down, so it builds up as the organism consumes it, and is not efficiently excreted.
• Biomagnification: The increase in the concentration of a substance through the food chain. As prey animals consume contaminated organisms, the concentration of the harmful chemical increases in the top predators. (Examples include mercury)

Other Important Terms

• Biodegradable and Non-Biodegradable items: Biodegradable items break down and decompose through microorganisms, while non-biodegradable items do not. (Examples of each are given.)

Explore the intricate relationships within ecosystems, focusing on the biotic and abiotic factors that define them. This quiz delves into the unique characteristics of the Sonoran Desert, including its wildlife and survival strategies in a challenging environment.