Dollo’s law:  A biological generalization positing that complex characters, once lost in evolution, are extremely unlikely to reappear and thus the loss of complex characters is virtually always irreversible.

TLS Online TPP Program

#Id: 6057

#Unit 10. Ecological Principles

Hot Desert  Temperatures are variable from below freezing at night to as much as 50ºC in the day. algae carry on photosynthesis and provide both themselves and the coral animals with the nutrients necessary for growth. 

The skeletons of the corals provide a surface upon which many other kinds of animals live.

TLS Online TPP Program

#Id: 6058

#Unit 10. Ecological Principles

 Cold Desert: In the daytime, temperatures can be high in the summer, 21–26ºC, but average around freezing, –24ºC, in the winter.

TLS Online TPP Program

#Id: 6059

#Unit 10. Ecological Principles

Tundra:   Tundra is found at high latitudes, adjacent to ice margins, where insolation is low.  Tundra is the youngest of all biomes as it was formed after the retreat of glaciers 10000 years ago.  Lack of light and rainfall mean (25 cm per year) that rates of photosynthesis and productivity are low. Large part of the year, water can be locked away in permafrost, a layer of permanently frozen soil below 0.5–1 m.

TLS Online TPP Program

#Id: 6060

#Unit 10. Ecological Principles

Mediterranean shrublands (chaparral):  These are located near an ocean and have wet, cool winters and hot, dry summers.  Rainfall is 40 to 100 centimeters per year. 

Fire is a common feature of this biome, and the shrubs are adapted to withstand occasional fires. 

TLS Online TPP Program

#Id: 6061

#Unit 10. Ecological Principles

Coral reef ecosystems  Most reefs are located between the Tropics of Cancer and Capricorn, in the Pacific Ocean.  Coral reefs are one of the most diverse ecosystems on our planet, yet they cover less than 1% of the Earth's surface. 

 

TLS Online TPP Program

#Id: 6062

#Unit 10. Ecological Principles

Zone of Lake