TROPICAL DESERT BY PATRICIA MANNING AND RYAN OLLIE

TROPICAL DESERT BY PATRICIA MANNING AND RYAN OLLIE PERIOD 2

SICENTIFIC NAME: SAHARA DESERT COMMON NAME: TROPICAL DESERT

WORLD LOCATION

BIOTIC FACTORS • Biotic factors are all the living things in an ecosystem. • Some biotic factors of the desert are: 1. Cacti 2. Aloe plants 3. Drought resistant- grasses 4. Rattle snake 5. Dessert cottontail

ABIOTIC FACTORS • Rainfall- Limited water is a key feature of any desert ecosystem. Typically deserts receive less than 20 in. of rain per year. Meaning that animals and plants living in these conditions must be able to live with little to no water for extended periods of time. • Soil- The type of soil an ecosystem has determines what plants can grow in them and also what animals can live in it. Desert soil types vary, changing certain location’s evaporation. Depending on the intensity of precipitation, rainfall or runoff may sink quickly into desert soil or form sudden flash floods producing significant erosion. • Light- The degree and intensity of sunlight in a given spot helps shape its climate and affects plants and animals. • Temperature- Deserts are ecosystems that go through various temperature fluctuations. A desert can be extremely hot during the day, and at night be freezing due to the missing heat of the sun. Organisms that cannot adapt have trouble surviving in these ecosystems. • Precipitation- Desert ecosystems have the most variable precipitation. That is, dry periods are very dry, and very long. Wet periods can be very wet. Organisms need to be able to adapt to these conditions or else they’ll have a hard time surviving.

CLIMATE • Average annual temperature- day time temperatures can go from 90 -120 degrees Fahrenheit, while night time temperature averages to 25 degrees. • Seasonal temperature- There is only 2 seasons, summer and winter. During the winter season, the temperature can be 15 to 25 degrees cooler. • Precipitation- About 9 inches of rain a year.

CLIMATE GRAPH

NET PRIMARY PRODUCTIVITY • NPP is the rate at which plants store energy or organic matter, not already used up in respiration. • NPP in desert- <200 (kilocalorie/square meter)

SUCCESSION • During succession, species become established and are then supplanted when conditions become more favorable for another species. • Succession usually follows a progression from colonizers through a series of intermediate stages until it reaches a climax community. • Primary succession occurs on land where there was no previous growth, and there is no substrate, or soil. • Secondary succession occurs on land where there has been previous growth before, and the substrate is made up of the soil and the seed bank.

FLOW OF STORE OF NUTRIENTS

HABITATS • Hot and dry deserts- Hottest type of desert with parched terrain and rapid evaporation. In this habitat, soils are coursetexted, shallow, rocky or gravely with good drainage and have no surface water. • Cool coastal deserts- located within the same latitudes as subtropical but the average temperature is much cooler because of frigid offshore ocean current. Soil is fine-textured with a moderate salt content. • Semi arid deserts- These deserts are known for their temperature differences from season to season. It ranges from 100 F degrees in the summer to 10 F in the winter. Their soil can range from sandy and fine textured rocks.

Niches

Food chain •

Food web

Energy pyramid

Biomass pyramid

Pyramid of numbers

Trophic levels

Animals and adaptations • Sand Boa- A Sand Boa is able to live up to 1 year without any food and has it’s eyes and nostrils positions in a way that prevents debris from harming those areas. • Sand Fish- The sand fish has a sharp snout that allows for it to sift through sand without it being harmed. • Brewer’s Sparrow- A brewers sparrow has a high metabolic rate and due to this are able to produce metabolic water that makes up for the lack of water they get in the hot desert conditions. .

Animals and Adaptations Cont. . • Sand Cat- Sand cats have padded paws with tough hairs that help protect the cats feet from hot sands and helps prevent them from sinking. • Desert Tortoise- These tortoises can carry more than 40 percent of there body weight od water in there bladders. Due to this they drink excess water and store it for when there is drought. • Desert Cockroaches- These cockroaches have bladders in there mouth that are able to condense water simply from moisture in the air.

Animals and Adaptations Cont. . • Cactus Bird- These birds have adapted beaks that allow them to drill nests for themselves in cacti in order to keep themselves protected. • Skin Drinking Desert Lizard- These lizards have adapted a method called cutaneous water acquisition, which allows them to use tubelike channels to absorb and direct water from rainfall and other sources throughout there bodies. • Desert Pupfish- Pupfish have adapted to be able to live in extremely hot conditions to the point that they are considered living fossils.

Plants and Adaptations • Drought Avoidance- Some plants avoid the drought season by dying before. Before dying they relay all there energy into producing as many seeds instead of saving them to try and survive. Brittlebrush • Succulence- Some plants store water in there fleshy leaves in order to save and store water for the dry season. • Drought Tolerance- Some Plants rely to methods such as shedding leaves and then going dormant in order to avoid dying during the dry season. Agave Plant

Case Study- Good Impact • Humans have several positive impacts on the desert. For example after wildfires, groups come together to replant the plants and organisms that dies in the fire. • Humans also have reservations meant to protect the endangered and threatened animals in the desert.

Case Study- Bad Impact u Humans are responsible for also causing pollution in the desert. Things such as drilling for fossil fuels and oil in the desert, pollutes the air and causes harm to the animals that live in the surrounding areas. This pollution has caused many animals to become endangered and extinct. This in general has and is ruining the ecosystem of the desert. Activity like offroading also affects the sand animals in the desert.