Biomes and Climate

Biomes Overview

• Biomes are large regions characterized by similar climate, soil, plant, and animal life.
• Terrestrial biomes are land-based, while aquatic biomes are water-based.
• Climate is the primary determinant of a biome, influencing the types of organisms that can thrive there.

Understanding Climate

• Climate is the long-term pattern of temperature, humidity, wind, and precipitation in a region.
• Latitude affects climate, with regions closer to the equator being warmer.
• Altitude influences climate, with higher altitudes being cooler.
• Ocean currents distribute heat globally, affecting coastal temperatures.
• Wind patterns carry moisture and heat, influencing regional climates.
• Proximity to water moderates temperatures and increases humidity in nearby land areas.

Terrestrial Biomes

Tropical Rainforest

• Location: Near the equator in South America, Africa, Southeast Asia, and Australia.
• Climate: Warm and wet year-round, with temperatures between 20°C and 25°C and abundant rainfall exceeding 200 cm annually.
• Vegetation: Dense, evergreen trees form a canopy; high species diversity.
• Animals: Rich biodiversity, including insects, birds, mammals, and reptiles adapted to living in trees.
• Adaptations: Plants have large leaves and drip tips; animals are adapted to tree-dwelling or dense undergrowth.

Savanna

• Location: Africa, South America, and Australia.
• Climate: Warm with seasonal rainfall (50-150 cm annually) and a prolonged dry season.
• Vegetation: Dominated by grasses with scattered trees and shrubs; drought-resistant plants.
• Animals: Large herbivores like elephants and zebras, and predators like lions and hyenas.
• Adaptations: Plants have deep roots and thick bark; animals migrate or have adaptations for running in open spaces.

Desert

• Location: North Africa (Sahara), Middle East, Australia, and southwestern United States.
• Climate: Extremely dry, with less than 25 cm of rainfall per year and extreme temperature variations.
• Vegetation: Sparse, with water-storing plants like cacti and spines to reduce water loss.
• Animals: Reptiles, rodents, and insects adapted to conserve water and nocturnal behavior.
• Adaptations: Plants have extensive root systems; animals minimize water loss and avoid heat.

Temperate Forest

• Location: North America, Europe, and Asia.
• Climate: Four distinct seasons with moderate rainfall (75-150 cm annually), cold winters, and warm summers.
• Vegetation: Deciduous trees (oaks, maples, beeches) and coniferous trees.
• Animals: Deer, bears, birds, and insects; many hibernate or migrate during winter.
• Adaptations: Deciduous trees shed leaves; coniferous trees have needle-like leaves; animals hibernate, migrate, or develop thick fur.

Tundra

• Location: Arctic and high altitudes on mountains.
• Climate: Cold and dry, with temperatures often below freezing, a short growing season, and little precipitation.
• Vegetation: Low-growing plants like mosses, lichens, and dwarf shrubs; permafrost limits root growth.
• Animals: Caribou, arctic foxes, and polar bears; many birds migrate in winter.
• Adaptations: Plants grow low to avoid cold winds; animals have thick fur, fat layers, or migrate.

Grassland

• Location: North America (prairies), South America (pampas), and Eurasia (steppes).
• Climate: Moderate rainfall (25-75 cm annually) with distinct seasons, hot summers, and cold winters.
• Vegetation: Dominated by grasses with few trees; fertile soil ideal for agriculture.
• Animals: Large herbivores like bison and antelope, and predators like wolves and coyotes.
• Adaptations: Plants have deep roots; animals are fast runners or live in protective burrows.

Aquatic Biomes

Freshwater Biomes

• Types: Rivers, lakes, streams, and wetlands.
• Salinity: Low, typically less than 1% salt content.
• Vegetation: Algae, floating plants, rooted plants; wetlands have grasses and trees.
• Animals: Fish, amphibians, insects, and birds; diverse microorganisms.
• Adaptations: Plants and animals adapted to low-salt environments; fish regulate water and salt balance; plants have flexible stems.

Marine Biomes

• Types: Oceans, coral reefs, and estuaries.
• Salinity: High, typically around 3.5% salt content.
• Vegetation: Algae, seaweeds, and seagrasses; coral reefs support diverse plant life.
• Animals: Vast range, from plankton to whales; coral reefs are high in biodiversity.
• Adaptations: Organisms adapted to high salinity with specialized glands; streamlined bodies for swimming; adaptations to temperature and light conditions.

Coral Reefs

• Marine biomes are known for biodiversity, found in shallow, warm waters, and built by coral polyps.
• Temperature changes, acidity, and pollution are major threats.
• Coral bleaching, caused by rising sea temperatures, leads to coral death due to the loss of symbiotic algae.

Introduction to Ecology

• Ecology is the study of interactions between living things and their environment.
• Ecosystems consist of living (biotic) and non-living (abiotic) factors.

Types of Ecological Relationships

Predation

• One animal (predator) hunts and eats another (prey).
• Helps control populations and maintains energy flow.
• Predators have adaptations like sharp teeth and claws; prey have defenses like camouflage or quills.

Competition

• Species compete for resources like food, water, or space.
• Occurs between different species or within the same species.
• Competition can lead to displacement, resource partitioning, or the evolution of new traits.

Symbiosis

• A close, long-term relationship between two different species.

Mutualism

• Both species benefit.
• Bees and flowers: bees get nectar, flowers get pollinated.
• Involves sharing resources or assistance with reproduction.

Commensalism

• One species benefits, the other is unaffected.
• Barnacles on a turtle: barnacles get a place to live, turtle is unaffected.
• Involves using another organism's habitat.

Parasitism

• One species (parasite) benefits at the expense of the other (host).
• Tapeworms in mammals: tapeworms absorb nutrients, harming the host.
• Causes disease and weakens the host.

Herbivory

• Plant-eating animals (herbivores) feed on plants.
• Plants have defenses like thorns or poisons; herbivores have adaptations like specialized teeth.
• Controls plant populations and influences nutrient cycling.

Amensalism

• One species is harmed, the other is unaffected.
• Black walnut trees release juglone, inhibiting the growth of nearby plants.
• Influences plant distribution.

Neutralism

• Species interactions have negligible effects on each other.
• A lizard and spider in the same area may not affect each other if they do not compete for resources.
• Impact on the ecosystem can be minor but influential.

Ecological Relationships and Ecosystem Stability

• Ecosystem stability depends on balanced ecological relationships.
• Changes in one population can affect the entire ecosystem.
• Keystone species have a disproportionately large impact on ecosystems.
• Sea otters control sea urchin populations in kelp forests.
• Trophic cascades are indirect effects caused by top predators on lower trophic levels.

Human Impact on Ecological Relationships

• Human activities disrupt ecological relationships globally.
• Deforestation, pollution, climate change, overfishing, and invasive species have negative impacts.
• Conservation efforts aim to preserve habitats, restore ecosystems, and protect endangered species.
• Introducing invasive species like the cane toad can devastate native predator populations.