3. Terrestrial Biomes

Biome

Geographic regions with organisms that have similar adaptations

- Defined by temperature and rainfall

- No sharp boundaries

- Distribution controlled by climate and disturbance

Weather

Short-term state of the atmosphere

- Changes with hours or days

Climate

Long-term patterns in weather

- Average weather over many years

Climography plots

Depict the amount of precipitation and temperature of a given biome

- Compare many biomes

Climate diagram (climograph)

Illustrates the annual variation in temperature and precipitation

- Regional

- Temperature on the left axis (degrees C)

- Precipitation on the right axis (mm)

- Aligned at 10 C and 20 mm

- Months on the x axis

Tropical Rainforest

Traits:

- High, constant rain

- High, constant temperature

- Vertical stratification (layering)

- High biodiversity

- Equatorial

- Fast nutrient cycling

- Epiphytes

Adaptations:

- Fast, lateral growth

- Buttress roots

- Mychorizae

- Thin bark

Epiphytes

Plants that grow on other plants

Tropical Dry Forest

Traits:

- Seasonal rain, dry with monsoon season

- High, constant temperature

- Equatorial

- Similar organisms to tropical rainforest

Adaptations:

- Small deciduous (shed) leaves

- Thick, thorny bark

Savannah (Tropical Seasonal Forest)

Traits:

- Seasonal rain

- High, constant temperature

- Grasses, sedges, herbs, small trees

- High animal diversity

- Prone to wildfires

Adaptations:

- Plants are drought, fire, and grazing-resistant

Desert (Subtropical)

Traits:

- Low rain, variable

- High, constant temperature

- Hot days, cold nights

- 30 degrees N + S

- Cacti, succulents, reptiles

Adaptations:

- Organisms adapt to reduce water loss or store water, or ways to dissipate heat

- Nocturnal behavior

- Spines to protect against herbivores

Cold Desert

Traits:

- Low SNOWY precipitation, but more than hot deserts

- Seasonal temperature; Freezing winters, moderate summers

- 20-30 degrees N + S

- Grasses, shrubs, diverse animals

- Mongolia, Patagonia

Adaptations:

- Plants are drought resistant

- Burrowing animals

Chaparral

Traits:

- Seasonal rain; Wet winters and dry summers

- Seasonal temperature; Hot summers and cool winters

- California, Spain, Italy

- Prone to wildfires and torrential rain

- Shrubs, small trees, grasses

- Hydrophobic soil

Adaptations:

- Fire and drought resistant plants

- Some plants require fire to germinate

Temperate Grassland

Traits:

- Seasonal rain; Rainy spring and summer

- Seasonal temperature; Hot summers and cold winters

- Fertile soil (Farmlands)

- Few trees

Adaptations:

- Plants are drought, fire, and grazing-resistant

- Plants have deep roots

Temperate Deciduous Forest

Traits:

- Moderate-high, constant rain

- Seasonal temperature; Freezing winters and hot summers

- Deciduous and Evergreen trees

- Foxes, squirrels, deer

Adaptations:

- Hibernation

- Migration

- Deciduous leaves

Boreal Forest (Taiga)

Traits:

- Moderate variable precipitation, rainy or snowy

- Seasonal temperature; Freezing winters and warm short summers

- North America, Eurasia (largest biome)

- Conifers

- Slow nutrient cycling, high leaf litter

- Acidic soil

Adaptations:

- Migration

- Hibernation

- Thick fur that changes color; Fat

Tundra

Traits:

- Low precipitation, snowy

- Seasonal temperature; Feezing winters (- 30 C) and cool short summers (10 C)

- Alpine (Mountaintop) tundra has significantly more rain than Artic tundra

- Permafrost layer restricts plant roots

- Lichens, mosses, shrubs

- Acidic soil

Adaptations:

- Thick fur and fat

- Plants have shallow roots

- Camouflage

Disturbance

An event that changes a community. Some biomes and plants depend on disturbances.

- Storm, hurricane

- Fire

- Flood

- Drought

- Grazing

- Human activity

Serotiny

Refers to seeds that germinate AFTER exposure to fire

- common in Chaparral biome

Convergent evolution

Evolution toward similar characteristics in unrelated species due to similar environments

This climograph best fits which biome?

Description: Seasonal temperature (freezing winters -20 C, warm summers 16 C) ; Seasonal low-moderate precipitation (rainy summer)

a. Temperate forest

b. Boreal forest

c. Temperate grassland

d. Tundra

b. Boreal forest

Temperate forests are characterized by hot summers and constant, high precipitation.

Temperate grasslands tend to have hot summers and rainier springs.

Tundras have even colder winters, cool summers, and less precipitation.

Which is a correct pairing of a biome and its characteristics?

a. Temperate Grassland - hot summers; freezing winters; many deciduous trees

b. Savanna - grasses and small trees; seasonal precipitation

c. Tropical dry forest - consistently little to no rain; hydrophobic soil

d. Cold desert - lichens and mosses; permafrost; cool summers

b. Savanna - grasses and small trees; seasonal precipitation

Temperate grasslands do not have many trees. The description better fits temperate deciduous forests.

Tropical dry forests are not known for having hydrophobic soil. That is a trait of the chaparral.

Cold deserts do not have permafrost, but Tundras do.

In which biome is fire resistance NOT a common adaptation?

a. Savanna

b. Chaparral

c. Temperate grasslands

d. Subtropical (hot) desert

d. Subtropical desert

Subtropical deserts are more adapted towards storing water and dissipating heat. Fires aren't as common of a concern.

What contributes to the patchiness of many biomes?

a. Disturbance

b. Climate change

c. Shallow roots

d. Temperature

a. Disturbance

Disturbances such as hurricanes and fires can clear the vegetation of an area, leaving it patchy.

What causes species in very separated locations to develop similar characteristics?

a. Coevolution

b. Evolutionary drift

c. Convergent evolution

d. Mutations

c. Convergent evolution