Impact of Plants/Introduction to Ecology

Why are plants important to life on Earth?

Plants produce oxygen, form the base of food chains, provide food, medicine, shelter, and fuel, regulate climate, cycle water and carbon, and support ecosystems.

How has agriculture changed human societies and the Earth?

Agriculture enabled permanent settlements, population growth, and civilizations. It changed landscapes through deforestation and irrigation and impacted ecosystems and climate.

How have humans changed wild and domesticated species?

Humans selectively bred wild plants for desirable traits, creating domesticated species that rely on human care and are genetically different from their wild ancestors.

What is the difference between cultivated and domesticated species?

Cultivated species are grown by humans, but not necessarily genetically altered. Domesticated species have been genetically modified through breeding for human benefit.

What are the main food crops that feed humanity?

The major food crops are rice, wheat, corn (maize), potatoes, Sweat potatoes, manioc (cassava, yucca)

What are plant fibers and how do humans use them?

Plant fibers are tough, stringy plant tissues like cellulose and lignin. Humans use them to make paper, clothing, rope, and other materials. You're likely wearing cotton (a plant fiber) right now.

What plant parts are used as fuel sources?

Wood (trunks/branches), seeds (like corn for ethanol), fruits (like sugarcane), and plant oils are burned or processed into biofuels.

What are the pros and cons of biofuels?

Pros: Renewable, lower carbon emissions, supports agriculture. Cons: Can compete with food production, cause deforestation, and require energy to produce.

What are ecosystem services?

Benefits nature provides to humans—like clean air, water, pollination, climate regulation, and soil fertility.

How do plants affect the soil?

Plants prevent erosion, add nutrients, support microbes, and maintain soil structure through roots and organic matter.

How do plants impact the carbon cycle?

Plants absorb CO₂ during photosynthesis and store carbon in their tissues, helping reduce greenhouse gases.

How do plants influence the water cycle?

Through transpiration, plants release water vapor into the air, contributing to cloud formation and rainfall.

How do plants affect climate?

Plants cool the environment through shade and transpiration, absorb CO₂, and influence rainfall and humidity.

What do morphine, taxol, and salicin have in common?

They're toxic plant-derived compounds (secondary metabolites) used in medicine for pain relief, cancer treatment, and anti-inflammatory effects.

What plants produce morphine, taxol, and salicin? What groups do they belong to?

Morphine – opium poppy (angiosperm); Taxol – Pacific yew (gymnosperm); Salicin – willow tree (angiosperm).

Why do plants produce toxic secondary metabolites?

To defend against herbivores, insects, and pathogens. These chemicals can deter, poison, or slow down attackers.

How are plant secondary metabolites important to humans?

Many are used as medicines, flavorings, stimulants, or poisons. They’re crucial in pharmacology and cultural practices.

What is Artificial Selection?

The human-directed breeding of plants or animals to encourage desirable traits.

What is an Ecosystem?

A community of living organisms interacting with their environment (air, water, soil).

What are Ecosystem Services?

Natural benefits ecosystems provide—like pollination, water purification, and climate regulation.

What is Transpiration?

The process where water evaporates from plant leaves, helping cool the plant and move water/nutrients.

What are Cellulose and Lignin?

Cellulose is a strong sugar-based fiber; lignin is a rigid polymer. Both give plants structure and are used in textiles, paper, and construction.

What is Ethnobotany?

The study of how people use and perceive plants, especially in traditional cultures and medicine.

What are Secondary Metabolites?

Chemical compounds plants produce not for basic survival, but for defense or signaling—often toxic or medicinal.

What is a Primary Producer?

An organism, like a plant, that produces its own food through photosynthesis and supports the food web.

What is Ecology?

Ecology is the scientific study of how organisms interact with each other and with their environment.

Why are environments changing more rapidly today than at almost any time in the past 3.5 billion years?

Human activity—like deforestation, burning fossil fuels, urbanization, pollution, and habitat destruction—has accelerated environmental change faster than natural processes (except for events like the mass extinction 66 million years ago).

What are the five main levels of ecological study?

Organismal Ecology, Population Ecology, Community Ecology, Ecosystem Ecology, Global Ecology

Organismal Ecology

Studies individual organisms’ behavior, physiology, and adaptations.

Population Ecology

Focuses on groups of the same species living together—examines population size, growth, and dynamics.

Community Ecology

Studies interactions between species living in the same area (e.g., predation, competition, symbiosis).

Ecosystem Ecology

Explores energy flow and nutrient cycling between organisms and the environment.

Global Ecology

Looks at the biosphere and how climate and human activities affect life on a global scale.

How are conservation ecologists like physicians?

They diagnose environmental problems (like habitat loss or pollution), prescribe solutions (such as restoration), and work to keep ecosystems "healthy."

Abiotic

Non-living environmental factors like temperature, water, sunlight, and soil.

Biotic

Living components in an environment, including plants, animals, fungi, and microbes.

Biosphere

The global ecosystem—all living organisms and their interactions with the Earth’s atmosphere, land, and oceans.

What is an organism’s range?

The geographic area where a species lives. This range is shaped by both abiotic and biotic factors, past and present.

What is a niche model?

A visual or mathematical representation of the environmental conditions and resources a species needs to survive. It can show tolerance ranges (broad vs. narrow).

What is a fitness trade-off?

When an organism evolves to do one thing well (e.g., survive cold), it may perform poorly in another area (e.g., competing in warm habitats). Adaptation involves compromise.

What determines a species’ range?

Abiotic factors: Temperature, water, sunlight, soil type.

Biotic factors: Predators, prey, competition, disease, mutualisms.

Why is temperature a major abiotic factor?

It influences metabolism, enzyme activity, reproduction, and survival—too hot or too cold and organisms can’t function.

How did the Isthmus of Panama impact dispersal?

It connected North and South America (terrestrial dispersal) but separated marine species in the Atlantic and Pacific (aquatic dispersal barrier). This event sparked the Great American Interchange.

Biogeography

The study of where species live and why.

Dispersal

The movement of organisms from one area to another.

Exotic Species

Species introduced by humans to a new area where they aren’t native.

Great American Interchange

The migration of animals between North and South America after the Isthmus of Panama formed.

Invasive Species

Non-native species that spread rapidly and harm native ecosystems.

Isthmus of Panama

A land bridge that formed ~3 million years ago, connecting two continents.

Native Species

Species that evolved in and naturally occur in a specific area.

Range

The total geographic area where a species lives.

Wallace Line

A biogeographic boundary in Southeast Asia that separates distinct animal communities.

What is a biome?

A large region characterized by specific climate conditions and plant communities. Plants define biomes because they shape the environment and support other life.

Key abiotic factors that influence biomes?

Temperature, precipitation, sunlight, wind, soil type, and elevation.

Six natural terrestrial biomes

Tropical Rainforest, Desert, Temperate Forest, Grassland (Prairie/Savanna), Taiga (Boreal Forest), Tundra,

Tropical Rainforest

Warm, wet, high biodiversity, dense plant cover.

Desert

Dry, sparse vegetation, adapted plants like cacti.

Temperate Forest

Moderate climate, deciduous trees, distinct seasons.

Grassland (Prairie/Savanna)

Seasonal droughts, grasses, fire-adapted.

Taiga (Boreal Forest)

Cold, coniferous trees, low diversity

Tundra

Very cold, permafrost, low shrubs, mosses, low productivity.

How is climate change affecting terrestrial biomes?

Climate change alters temperature and rainfall patterns, shifting plant and animal communities and disrupting ecosystems across biomes.

What are anthropogenic biomes (anthromes)?

Biomes heavily influenced by human activity—urban areas, croplands, rangelands.