AIM: SWBAT describe the unique features of the tropical grassland/savanna biome Please Do Now: What, in terms of climate, separates the temperate grassland from the temperate forests?
Agenda • Do Now • Begin Savanna Notes • Savanna Video • Return Exams
Tropical Grassland/Savanna • Found near the equators in place to dry to support a forest. Largest examples are found on Africa and South America
Out of order *Unique sub-habitats* out of order • The tropical grassland consist of just grass, while the savanna has widely spaced trees also. Their animal communities are very similar and that is why they are grouped together. They are found right next to each other in many locations.
Climate • Precipitation is variable with a wet season and a dry season • Temperature are hot throughout the year
Soil • Like the temperate grasslands, the soils tend to be very rich, with lots of organic content, which is replenished by the frequent wildfires.
Plant Life • characterized by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses
Plant’s Adaptations • Trees have thick bark, thorns, loose leaves in dry season • Grasses grow in clumps, shoots (aboveground tissue) dies during dry season
Seasonal Variation • In terms of temperature, very little • In terms of precipitation, very high. There is a marked dry season and wet season, which drive the migrations here, the largest on earth
Limiting Factors and Adaptations • On your own
Diversity and Productivity • Above average diversity, thanks to the many micro-habitats, and high productivity • Productivity: 8
DO NOW • What is likely the limiting factor for herbivores in the savannah? (Write on the packet in 3 minutes or no credit).
Agenda • Do Now • Anteaters • Savannah • Video
Succession • The savannah biome is constantly changing, wildfires restart succession all the time, with tough grasses regrowing quickly after, and some trees with fires resistant bark surviving largely intact • When the climate changes (for the drier or wetter) trees die off or grow more dense • Animals themselves also influence succession. The savannah would probably have many more trees than it does if it were for the damage large herbivores like elephants do to young trees
Keystone species • The elephants use their huge size to take down trees, which keeps the savannah open canopied for grasses to grow • Termites are very common on the savannah, and convert the energy in grasses and wood to more edible forms
Migrations • Extremely common because of the dry season. • Grazers move to find areas with better grass to rear their young • Predators follow or attack them along the route
Mating Systems • Lek mating and polygyny is common in the grazers of the tropical grasslands and savannah • Lions and some other big cats are famous for their polygynous mating habits (alpha males)
Example organisms / Trophic Pyramid • During the video
Symbioses • Many birds live off the bugs that parasitize large herbivores • Example: oxpecker • Also, acacia trees have a protective symbioses with stinging ants
Threats to Conservation • Conversion to farmland or cattle pasture • Poaching of the important large herbivores
AIM: The savanna continued Please Do Now: Think about it (hard question) write minimum 2-3 sentences. Why might the structure of the savanna (grasslands with trees) be more likely to have high biodiversity than a plain tropical grassland?
Agenda • Do Now • Few Savannah Slides • Explain tomorrow • Correct Midterms
Famous Examples • The Cerrado of Brazil • The Serengeti of East Africa
Vocabulary • Perennial: In reference to plants, a life-strategy where individual plants live more than one year (usually above ground parts die and are regrown from the roots) (opposite of perennial = annual) • The grasses in the savannah are almost all perennials
Tomorrow • Tomorrow we will be in the computer lab, where you will use the internet to fill in a packet on your own (so exciting YAY) • It will count as half your quiz grade for the week • The biome will be: Mediterranean forests
Correcting your exams • On loose leaf WITH justifications for those you got incorrect