The distribution of plants and animals on the earth is determined by the climate conditions, the size of the landmass, ocean currents and mountain ranges.

Biogeography examines the distribution of plant and animal species in the past and present. Species distribution, behavior and habitat selection, biotic and abiotic factors that affect the geographical distribution of living things are in the field of biogeography.

1. Distribution of Species

Species dispersal is the spread of an organism from an area where it is found to other areas where it can reproduce. Biotic and abiotic factors affect the distribution of the species.

2. Behavior and Habitat Selection

In the event that geographical conditions change, food sources decrease and diseases increase, living things migrate to new environments or try to adapt to the changing environment.

3. Biotic Factors

The biotic factors consisting of animals, plants, fungi and microorganisms are in direct or indirect relationship with the elements of the environment.

4. Abiotic Factors

Abiotic factors such as temperature, water, sunlight, wind, soil, minerals affect the geographical distribution of organisms.


The community that includes many populations and the inanimate environment surrounding the community are called ecosystems .

A biome is an ecosystem type that has a distinctive climate, vegetation, and animal community .

All of the various ecosystems found on Earth are collectively defined as the ecosphere.


Biomes are large ecosystems encompassing large geographic regions. Biomes are examined in two groups as terrestrial and aquatic.

1. Terrestrial Biomes

The distribution of living things on earth is largely dependent on climatic conditions. Climatic conditions vary according to latitudes and landforms. Although biomes are not separated by precise boundaries, they intersect in certain regions. Biomes are usually named for the dominant plant species they contain. terrestrial biomes; They are grouped into forest, desert, and grassland biomes.

Forest Biomes

a) Tropical rain forests:
 Annual precipitation is high and regular. High temperature and humidity increase biodiversity.

The vegetation is broad, dark brown, thick-leaved and evergreen, herbaceous and short plants live in the lower part of the forest.

The characteristic animals of these forests are birds, bats, snakes, monkeys, cougars, jaguars, crocodiles, etc.

b) Temperate deciduous forests: There are tree species adapted to dry and rainy seasons. Trees shed their leaves in winter. Beech, chestnut, oak, linden, elm, alder. Shrub and grass species are well developed and very diverse in old forests.

The characteristic animals of these forests are deer, bear, fox, lynx, weasel, squirrel, partridge, some reptile, amphibian and insect species.

c) Coniferous biomes:
 It is the biome where conifers grow in the humid and cool climate zone.

Dominant vegetation; grows spruce, fir, red pine, etc. In these forests, hedgehogs, deer, lynx, hawk, bat, bear, and some insect species are found.

Desert Biomes

While the temperature in the desert is very high during the day, a sudden decrease is observed at night. Precipitation is very low and humidity is accordingly low.

A scattering of thickets is found in a tropical desert. Cactus and similar plants grow.

Animals that need little water and can store water can live in the desert. There are foxes, rabbits, lizards, snakes, opossums and some insect species.

Grassland Biomes (Temperate Grassland)

Summers are hot and winters are cold. They are regions that receive a lot of rain in winter and less rain in summer, and where there is no desertification. There is vegetation dominated by meadows. Legumes and cereals are grown.

Grasslands especially herbivorous animals such as cattle, sheep, goats, foxes, sparrows, badgers, larks, etc. live in meadow biomes.

2. Aquatic Biomes

They are grouped into freshwater and saltwater biomes.

Freshwater Biomes

a) Lake biomes: Communities in lakes are distributed according to the depth of the water and the distance to the shore.

Lake biomes inhabit algae , cyanobacteria, plankton, frogs, perch, migratory waterfowl, carp, aquatic plants, reeds, water lilies, etc.

b) Stream biomes: In ecosystems at river mouths, water is very variable in terms of salinity, temperature and nutrients. There are many living species that have adapted to the environment here.

Trout in cold and clean streams, carp in streams and rivers, as well as mollusks, algae and sponges live in areas where the current is fast.

c) Wetlands: Natural or artificial; stagnant or flowing waters; reeds, reeds and lake lilies inhabit a wide variety of animal species.

Saltwater Biomes

Oceans and seas are saltwater biomes. Light, temperature, pressure, amount of salt, sea currents and tides, dissolved substances, amount of nutrients and active gases have great effects on the species and population size in the seas.

In the marine ecosystem, types of plankton, cartilaginous and bony fish from vertebrates, a few reptiles and mammals (seal, whale); Among the mollusks, there are shrimp and some crab species, worms and jellyfish.