Biomes

What is a Biome?

• Biomes are large regions characterized by a specific type of climate and certain types of plant and animal communities.– Each is made up of

many different ecosystems.

Biotic factors

• Biological influences biomes are called biotic factors or biota.

Example of biotic Example of biotic factors:factors:

PlantsPlants

AnimalsAnimals

FungiFungi

BacteriaBacteria

MicroorganismsMicroorganisms

Abiotic Factors

Physical, or nonliving, factors that shape ecosystems and biomes.

Aquatic Life Zones• Light penetration • Water currents• Dissolved nutrient

concentrations (nitrogen and phosphorus)

Terrestrial • Sunlight• Temperature• Precipitation • Wind• Latitude• Altitude• Soil

Biomes and Vegetation

• Biomes are described by their vegetation.– Plants in a Biome have

adaptations to their environment.• Examples – size, shape

and color

Biomes and Climate

• Climate is the average weather conditions in an area over a long period of time.– It determines which plants grow in an

area.– Temperature and precipitation are the 2

most important factors that determine a region’s climate.

Temperature and Precipitation

• Organisms are adapted to certain ranges of temperature in their environment.

• Precipitation limits organisms that can be found in a biome.– The higher the temperature and

precipitation are in an area, the taller and denser the vegetation.

Biodiversity

A World Rich in BiodiversityA World Rich in Biodiversity

• Certain areas of the planet, such as Certain areas of the planet, such as tropical tropical rainforestsrainforests, contain an extraordinary variety of , contain an extraordinary variety of species.species.

• HumansHumans need to understand and preserve need to understand and preserve biodiversity for our own survival.biodiversity for our own survival.

• Every species is probably either Every species is probably either dependentdependent on or on or depended upon by at least one other species in depended upon by at least one other species in ways that are not always obvious.ways that are not always obvious.

• When one species disappears from an ecosystem, When one species disappears from an ecosystem, a strand in a a strand in a food webfood web is removed. is removed.

Biodiversity at RiskBiodiversity at Risk

• The extinction of many species in a relatively The extinction of many species in a relatively short period of time is called a short period of time is called a Mass Extinction.Mass Extinction.

• Earth has experienced several mass extinctions, Earth has experienced several mass extinctions, each probably caused by a global change in each probably caused by a global change in climate.climate.

• It takes millions of years for biodiversity to It takes millions of years for biodiversity to rebound after a mass extinction.rebound after a mass extinction.

How Do Humans Cause ExtinctionsHow Do Humans Cause Extinctions

• In the past 2 centuries, human population In the past 2 centuries, human population growth has growth has acceleratedaccelerated and so has the rate and so has the rate of of extinctions.extinctions.

• The major causes of extinction today are The major causes of extinction today are the the destruction of habitatsdestruction of habitats, the introduction , the introduction of of nonnative speciesnonnative species, , pollutionpollution, and the , and the overharvestingoverharvesting of species. of species.

– Poaching Poaching is the illegal harvesting of fish, is the illegal harvesting of fish, game, or other species.game, or other species.

Tiger PoachingTiger Poaching

Invasive Exotic SpeciesInvasive Exotic Species

• An An exotic species (invasive)exotic species (invasive) is a species is a species that is not native to a particular region.that is not native to a particular region.

• Even familiar organisms such as cats and Even familiar organisms such as cats and rats are considered to be exotic species rats are considered to be exotic species when they are brought to regions where when they are brought to regions where they never lived before.they never lived before.

• Exotic species can threaten native Exotic species can threaten native species that have no natural defenses species that have no natural defenses against them.against them.

Dandelion- InvasiveDandelion- Invasive

PollutionPollution

• PesticidesPesticides, cleaning agents, drugs, and other , cleaning agents, drugs, and other chemicals used by humans are making their chemicals used by humans are making their way into food webs around the globe.way into food webs around the globe.

• The long term effects of chemicals may not The long term effects of chemicals may not be clear until after many years.be clear until after many years.

• The bald eagle was endangered because of a The bald eagle was endangered because of a pesticide known as pesticide known as DDTDDT. Although DDT is now . Although DDT is now illegal to use in the United States, it is still illegal to use in the United States, it is still manufactured here and used around the manufactured here and used around the world.world.

Balancing Human NeedsBalancing Human Needs

• Attempts to protect species often come into Attempts to protect species often come into conflict with the interests of the world’s conflict with the interests of the world’s human human inhabitants.inhabitants.

• An endangered species might represent a An endangered species might represent a source of food or income. Or a given species source of food or income. Or a given species may not seem valuable to those who do not may not seem valuable to those who do not understand the species’ role in an ecosystem.understand the species’ role in an ecosystem.

• Many conservationists feel than an important Many conservationists feel than an important part of protecting species is making the value part of protecting species is making the value of biodiversity understood by more people.of biodiversity understood by more people.