Biosphere, Climate Change, and Biodiversity Overview

Biosphere

The global collection of all Earth's ecosystems where life exists.

Human Role in Biosphere

Humans alter ecosystems through pollution, deforestation, resource use, and can also act as stewards via conservation.

Biotic Factors

Living components (plants, animals).

Abiotic Factors

Nonliving components (sunlight, temperature, water).

Climate

Long-term average atmospheric patterns.

Weather

Day-to-day conditions.

Greenhouse Effect

Trapping of heat by gases like CO₂ and CH₄ in Earth's atmosphere.

Gas Responsible for Greenhouse Effect

Carbon dioxide (CO₂).

Global Warming Contribution to Climate Change

It increases Earth's average temperature, causing shifts in weather, ocean levels, and ecosystems.

Consequences of Climate Change

Sea level rise, stronger storms, ocean acidification, habitat loss, species extinction.

Detailed Consequence of Climate Change

Coral bleaching occurs when warm, acidic water stresses coral, causing it to expel algae and die.

Ecological Footprint

A measure of the human impact on Earth's resources, including carbon emissions, land, and water use.

Population Size

Total number of individuals.

Population Density

Number per unit area.

Exponential Growth

Rapid population increase without environmental limits (J-curve).

Logistic Growth

Population growth that slows as it reaches carrying capacity (S-curve).

Carrying Capacity

The maximum number of individuals an environment can sustainably support.

Density-Dependent Limiting Factors

Factors that intensify with population size (e.g., disease, competition).

Density-Independent Limiting Factors

Factors not affected by population size (e.g., fire, drought).

Predator-Prey Cycle

Linked population fluctuations between predators and their prey.

Ecological Community

All living species interacting in an area.

Ecological Diversity

Species richness (variety) and relative abundance (balance of species).

Food Chain

Simple line of energy flow.

Food Web

Complex interconnected chains.

Keystone Species

A species whose presence or absence has a disproportionately large impact on the ecosystem.

Major Species Interactions

Name and define the four major species interactions.

Predation

one eats another

Competition

fighting for same resource

Mutualism

both benefit

Parasitism

one benefits, one harmed

Primary succession

Ecosystem development starting from bare rock with no soil (e.g., after lava flow)

Secondary succession

Ecosystem recovery after disturbance where soil remains (e.g., after fire)

Ecosystem

community plus abiotic factors

Community

all species in an area

Energy flow

One-way flow: Sun → Producers → Consumers → Decomposers; ~90% lost at each level as heat

Nutrient cycling

Nutrients (e.g., carbon, nitrogen) are recycled between organisms and the environment

Energy pyramid

Diagram showing energy loss at each trophic level, typically with 10% energy transfer efficiency

Primary productivity

The rate at which producers make biomass via photosynthesis; determines energy available to ecosystem

Productivity

Highest in estuaries and rainforests; lowest in deserts and open ocean

Water cycle

Cycle of water through evaporation, condensation, precipitation, infiltration, and runoff

Carbon cycle

Cycle of carbon through photosynthesis, respiration, combustion, and decomposition

Biomes

Kelp Forest, Open Ocean, Chaparral, Desert, Montane Forest, River, Estuary

Whale evolution evidence

Fossils show transition from land mammals; vestigial limbs, DNA, blowhole position support aquatic ancestry

Antibiotic resistance in bacteria

Through natural selection: resistant bacteria survive antibiotics and reproduce

Penguin speciation

Geographic isolation and environmental pressures lead to new penguin species

Climate change impact on penguins

It alters breeding areas and reduces food sources like krill

Fossils and bird evolution

New fossils (e.g., Archaeopteryx) show dinosaur-bird transition with feathers and bone structures

Speciation

The process where one species splits into two due to reproductive isolation and genetic divergence

Biodiversity

The variety of all life forms, from genes to ecosystems

Mass extinctions

Catastrophic events like asteroid impacts, volcanic activity, or rapid climate change

Chapters for Evolution & Biodiversity unit

Chapter 11 (Natural Selection), 12 (Speciation), 13 (Fossils), 14 (Biodiversity & Extinction)