Question

List the characteristics of a savanna. What evolutionary adaptations are thought to have been caused by fires?

Discuss the adaptations exhibited by desert plants.

Discuss the efforts by humans to develop renewable sources of energy from plants.

How does secondary succession differ from primary succession? Give three examples of secondary succession from your own experience.

Answer 1

Answer 1-

Characteristics of savanna ecosystem :

a)Savanna grassland and temperate grassland are the two main types of grassland biomes.

b)Savanna biomes are found between tropical rainforest and desert biomes. They share certain characteristics of both.

This transitional grassland ecosystem

- Somewhere between a forest and a desert

- Characterized by warm temperatures, moderate rainfall, fires, seasonal droughts, coarse grasses and diverse animals

Answer2-

Desert plants and their adaptations:
- barrel cactus has long, sharp spines that have replaced leaf structures. The cactus benefits through reduced water loss (because of the hardened leaf structures) and protection from being eaten by animals. Typically, leaves lose water in transpiration. But the long, sharp spines of the barrel cactus avoid this process. Also, this plant does not produce seeds each year because it is too labor intensive. Instead, it grows smaller versions of itself which break off and roll away and plant elsewhere so there are more of that cactus. This cactus can photosynthesize right away too which allows it to thrive.

- jumping cholla: cactus has short spines that come out in the center to grab onto people who pass by. This allows the cactus to spread since it sticks to people passing by. Then it can grow in new places.

- Ocotillo: plant drops its leaves when it is try and then grows them back when there is moisture. This allows the plant to go through photosynthesis without the leaves.

- Boojum tree: has short spreading branches that allow it to conduct photosynthesis in the absence of moisture (like in the desert).

- Saguaro cactus: its spreading branched roots are shallow which means it can take better advantage of rainfall which sinks to the top of the soil.

- California Poppy: this flower can grow in the desert because it is desirable. When a plant has desirability, it can grow in an area where it is not native.

Answer 3-

Humans has made efforts in making Biofuel that helps in producing different types of fuel we use in our vehicles (though normally and typically diesel) from plants or other organic matter rather than from the fossil fuels extracted from the ground. Biofuels are produced different ways:

• Direct processing of a raw plant material, such as extracting its natural oils, and processing it into a type of fuel
• Extractiong residues or decomposed matter as a result of natural anaerobic processes (such as broken down by bacteria or algae into an alcohol substance - bioethanol)

Biomass is different from biofuel in that it is waste organic material such as wood and other plant matter, and not a derivative byproduct that results from processing. Biomass is chopped wood (logs and kindling), grasses, leaves, brush and scrub, and other raw organic material that may burn and produce energy, including manure and animal dung. In the past, and indeed in areas where there are few trees to burn as fuel (Arctic Circle) people may burn bone or as a source of fuel .

Answer 4-

A Primary succession is one of two types of biological and ecological succession of plant life, occuring in an environment in which new substrate devoid of vegetation and other organisms usually lacking soil, such as lava flow or area left from retreated glacier is deposited.

Process of primary succession

1. Bare rock, no organisms -Glaciers leaves behind bare rocks, Volcano produces bare rock with no organisms.

2. Pioneer species begins breaking down rocks. Pioneer species: first organism to live in an area.Pioneer species, usually lichens, grows on rock. Lichen secretes acids that begin breaking rock into small particles, which mix with lichen begin to remain making soil.

3. More complex plants, usually mosses, begin growing when soil is deep enough, after many years eventually replace lichens. Tiny organisms such as insects move in, add their remain to soil.

4. Larger, more complex plants: As soil gets thicker ferns succeed mosses. Grasses and wildflowers may succeed ferns.When enough soil has developed, shrubs and small trees move into the area.

5. Forests: soil may be deep enough after hundreds or thousands of years for pine or hardwood forests.

B In respect of secondary succession,

Secondary succession occurs on substrate that previously supported vegetation before an ecological disturbance from smaller things like floods, hurricanes, tornadoes and fires which destroyed the plant life.

Example - Primary Succession

Island of Surtesy

Example- Secondary Succession

Forest fire