L10.1 Savanna Biome Flashcards
How can a Savanna be described
A continuous layer of grasses with a discontinous layer of trees
What is the photosynthetic method of grasses in savanna
C4
What is the photosynthetic method of trees in the savanna
C3
Is a savanna heterogenous or homogenous
Heterogenous
Why are savanna ecosystems often percieved as ecologically puzzling
Can be varied (e.g. In terms of wood density, succession state)
Are savannas disturbed
Highly
How much of the earths land is savanna ecosystems
25%
Where do savannas occur
Tropics and subtropics
What are the usual climatic conditions in a savanna
Climate will vary due to global distribution
Warm temperatures
Varied rainfall (300-1000MAP)
Wet and dry season
What biome are you in if the rainfall is below 300 MAP
Desert
What are the 2 predominant disturbances in savannas
Herbivory and fire
Why are savannas burned on purpose
To mitigate the fires effects - controlled
Reduces implications when fire happens naturally
How do trees defend against herbivory
Thorns
What group of animals are herbivorous in savanans
Browsers
How do fires benefit savannas
Kills grass layer but rarely causes tree mortality
Allows trees to grow in abscence of competitive grasses
What is a Gulliver tree
A tree which stays trapped in the fire zone for years
Resprouts quickly after fire from roots byt do not develop enough before the next fire so are killed repeatedly
What are some challenfes to plants in a savanna
Water stress
Fire
Predation
Inter-competition with other plant forms for resources (trees and grasses)
Nutrirnt availability
Adaptive traits of savanna trees
Nitrogen fixer
Spines
Small compound leaves
What is the sap of savanna trees like and why
Watery to reduce flammability
What is the stem of the Bao bab like
Spongy and eventually hollow
How many families of acaisa are there and how are these seperated
2 - determined by locaion
What is the name for acasias found in Africa
Fatelu
Why do some savanna trees have milky sap
Deterant against herbivory
Poisonous, can cause skin rashes and blindness
What are some adaptations of Fabeaceae (leaf and stem structure, reproduction)
Nitrogen fixers
Bipinnate leaves
Multi-stemmed
Reproduces from root (vegetatively)
What is more productive in a savanna: grasses or trees
Grasses
What happens to C4 savanna grasses if the canopy becomes more closed
Replaced by C3 grasses
How can savanna grasses reproduce
From seed or resprout from roots if not damaged
What makes savanna grasses fierce competitors
More responsive roots
Gain height more quickly
Higher reproduction rates
