Biol 1110-Climates and Biomes

What is climate, and what are its main components?

Climate is the long-term prevailing weather conditions of an area. Its components include temperature, precipitation, sunlight, and wind.

What determines global climate patterns?

Solar energy and Earth's movement in space. Uneven heating causes temperature variations, air and water movement, evaporation, and latitudinal climate differences.

What causes seasonal climate changes?

Earth's tilted axis and its annual orbit around the Sun

How do seasonal changes affect rainfall and ocean productivity?

• Moving air belts → wet/dry seasons

• Changing winds → ocean upwelling

• Upwelling → nutrients rise → phytoplankton growth

How do ocean currents and large bodies of water influence climate?

• Currents heat or cool coastal areas

• Water moderates nearby temperatures

• Example: California Current → cool coastal climate

How do mountains affect precipitation and temperature?

• Windward: Air rises, cools, releases moisture

• Leeward: Dry air descends → rain shadow

• Mountains also affect sunlight, temp and rainfall

What is a microclimate, and what influences it?

A microclimate is a localized pattern of climatic conditions influenced by shade, evaporation, and wind patterns.

How do forests affect their microclimate compared with cleared areas?

Forests reduce sunlight, wind, and evaporation, creating cooler, more humid conditions. Cleared areas experience greater temperature extremes.

What are abiotic and biotic environmental factors?

Abiotic factors: nonliving physical and chemical conditions, such as temperature, light, water, and nutrients

Biotic factors: living influences on the distribution and abundance of organisms.

What is climate change, and how can it affect species distributions?

Climate change is a directional change in global climate lasting at least three decades.

Species may lose suitable habitats or be unable to migrate quickly enough as conditions change.

What is a biome, and what primarily determines terrestrial biome distribution?

A biome is a major ecosystem type occupying a large geographical area. Terrestrial biomes show strong latitudinal patterns and are primarily determined by temperature and precipitation.

What is an ecotone, and why is it ecologically important?

An ecotone is a transition area between biomes where communities intergrade. It can form a continuous gradient and allow species from different communities to coexist.

What are the vertical layers of a forest and grasslands?

• Forest: Canopy → low-tree → shrub → herbaceous → litter → roots

• Grassland: Grasses/forbs → litter → roots

How does vertical layering benefit animals?

It creates different habitats and feeding opportunities. Birds and bats may feed above the canopy, while small mammals, worms, and arthropods forage in litter and root layers.

How do disturbances influence biome structure and species composition?

• Create openings and habitat patches allowing communities to coexist

• Fires prevent savannas becoming woodlands

• Hurricanes open forest canopies

• Pests allow deciduous trees to grow

What characterizes tropical forests?

Location: Equatorial/subequatorial

Temperature: 25–29°C year-round

Rainfall: Constant in rainforests; seasonal in dry forests

Plants: Evergreen trees, canopy layers, epiphytes (bromeliads and orchids)

Dry forests: Thorny shrubs, succulents

Animals: Highly diverse; insects, arthropods, amphibians, reptiles, birds and mammals

Human impact: Agricultural deforestation

What characterizes deserts?

Location: Near 30° N/S or continental interiors

Rainfall: Low, variable

Temperature: Extreme; above 50°C to −30°C

Plants: Cacti, succulents, shrubs

Adaptations: Water storage, reduced leaf surface area, spines and chemical defenses against herbivores

Animals: Snakes, scorpions, ants, beetles etc; Many nocturnal; conserve water

Human impact: Water transport and groundwater support populations

What characterizes temperate grasslands?

Location: Middle latitudes (prairies, pampas, veldts)

Climate: Cold, dry winters; hot, wet summers

Plants: Grasses and forbs; drought/fire adapted, grasses sprout quickly after fires

Animals: Bison, wild horses, prairie dogs

Human impact: Agriculture; overgrazing can cause desertification

What characterizes temperate deciduous forests?

Location: Mid-latitudes (NA, W/central Europe, EA)

Rainfall: 30–60 inches/year, evenly distributed

Temperature: Warm/hot summers; cold winters (30°C to −30°C)

Plants: Oak, maple, beech; shed leaves in autumn, forests have distinct vertical layers to support many animals

Animals: Mammals, birds, reptiles, amphibians, insects

Human impact: Logging, agriculture, pollution, invasive species

What characterizes tundra?

Location: Arctic and high mountains (alpine)

Precipitation: Arctic 20–60 cm/year; alpine may exceed 100 cm

Temperature: Winters around −30°C; summers below 10°C

Plants: Mosses, grasses, lichens, dwarf shrubs

Permafrost: Frozen soil restricts root growth

Animals: Caribou, reindeer, musk oxen, predators, migratory birds

Human impact: Oil and mineral extraction

What characterizes taiga?

Location: Northern North America, Europe, Asia

Climate: Long, freezing winters; short summers

Precipitation: Summer rain, winter snow

Soil: Nutrient-poor; slow growing seasons

Plants: Spruce, birch, mosses, lichens

Animals: Moose, snowshoe hares, lynx

Adaptations: Thick fur, fat reserves, hibernation, migration

Human impact: Logging, pollution, climate change

What characterizes coastal temperate rainforests?

Location: Western North America, northern California to Alaska

Climate: Heavy cool-season rainfall; mild summers

Plants: Western hemlock, Douglas-fir, salal, mosses

Animals: Black bears, wolves, bald eagles, banana slugs

Human impact: Logging/industrial degradation, fires, climate change, urbanization

How do light and temperature vary with lake depth?

• Light decreases with depth

• Stratification: Water layers differ in conditions

• Thermocline: Layer of rapid temperature change

• Temperate lakes: Seasonal thermocline

• Tropical lakes: Thermocline year-round

How do oligotrophic and eutrophic lakes differ?

Oligotrophic lakes: nutrient-poor and oxygen-rich, with little decomposable organic matter

Eutrophic lakes: nutrient-rich and oxygen-poor because abundant organic matter decomposes and consumes oxygen.

How does nutrient enrichment affect lakes?

• Runoff adds nutrients and sediments

• Algal blooms increase

• Decomposition consumes oxygen

• Oxygen depletion can kill fish

What organisms inhabit lakes?

• Shallow water: Rooted/floating plants

• Deeper water: Phytoplankton, cyanobacteria

• Consumers: Zooplankton, fish, invertebrates

What characterizes wetlands?

• Periodically/permanently waterlogged

• Oxygen-poor soils due to decomposition

• Filter nutrients and chemical pollutants

• Help reduce peak flooding

What organisms inhabit wetlands, and how are they affected by humans?

• Plants: Cattails, sedges, sphagnum moss, tamarack, black spruce

• Animals: Invertebrates, birds, insects, crustaceans, muskrats

• Food: Living plants/algae and dead plant material

• Human impact: Draining and filling

How do headwater streams differ from downstream rivers?

• Headwaters: Cold, clear, swift, turbulent, narrow, rocky, oxygen-rich

• Downstream: Wider, warmer, more turbid; may have less oxygen

• Soil and rocks influence nutrients and pH

What organisms inhabit streams and rivers, and what threatens them?

• Producers: Phytoplankton, periphyton

• Consumers: Fish and invertebrates

• Terrestrial plant material is a major food source

• Threats: Municipal, agricultural, industrial pollution

What characterizes estuaries?

• Transition between river and sea

• Rising tide: Seawater moves upstream

• Falling tide: Water moves downstream

• Denser seawater lies beneath river water

Why are estuaries highly productive?

• River nutrients support high productivity

• Salinity ranges from fresh to seawater

• Producers: Salt-marsh grasses, algae, phytoplankton

• Animals: Worms, oysters, crabs, fish, waterfowl, marine mammals

• Provide breeding, feeding, and migration habitats

What threatens estuaries?

• Filling

• Dredging

• Upstream pollution

What conditions do coral reefs require?

• Calcium carbonate coral skeletons

• Solid substrate for attachment

• Temperatures generally between 20–30°C

• High oxygen; harmed by excessive nutrient inputs

How do coral reefs develop, and which organisms inhabit them?

• Fringing reef → may develop into offshore barrier reef

• Mutualism: Dinoflagellates live in coral tissue

• Red/green algae, corals, diverse fish and invertebrates

What threatens coral reefs?

• Coral collection

• Overfishing

• Global warming

• Pollution

What are the five open-ocean zones, from the surface to the greatest depths?

Epipelagic, mesopelagic, bathypelagic, abyssopelagic, and hadopelagic.

How do conditions change with open-ocean depth?

• Light decreases with depth

• Deepest zone: No light, extreme pressure

• Water: Slightly alkaline and salt-rich

• Gas exchange and currents influence chemistry

Which organisms inhabit the open ocean?

• Producers: Phytoplankton, cyanobacteria

• Consumers/heterotrophs: Bacteria, archaea, zooplankton, large fish, marine mammals, seabirds

What threatens open oceans?

• Climate change

• Industrial fishing

• Pollution

• Resource extraction