The Desert

Biotic organisms

Lynx     Rattlesnakes    Horned toads    Hare   Cacti

Abiotic organisms

Sand    rocks   soil    air   water

Carrying capacity and changes in population

Carrying capacity- The largest number of individuals of one species that an environment can support.

Resources needed to survive

Food, water, shelter, and space

Changes over time

If some resources are not available the population can either decrease or increase. For example: If a hare population is low then the lynx population will suddenly have a decrease too or if the hare population is high then the lynx population will increase too.

Limiting factors

Limiting factors- Any factor or condition that limits the growth of a population in an ecosystem

Predator/Prey relationship

If the hare population dies off from diseases or not enough food then the lynx population would die off or vise versa, if the hare population doubled then the lynx population would double.

Energy Roles

The sun give radiant energy to the producers, then it is transformed into chemical energy and passed onto the primary consumers, then it is transformed into mechanical energy which is passed onto the secondary consumers, finally it is transformed into thermal energy and passed onto the tertiary consumers.

Receiving energy

Each animal gets 10% of its energy from lower level consumers an the other 90% is used to carry out life functions.


Producers are important because it passes off the first energy and they start the whole cycle

Food chains and food webs

Food webs are more realistic because they show all the possibilities there are while food chains just go in one direction and only show one outcome.

Removing populations

If you took out plats from the habitat, soon the primary producers will die, then the secondary, etc.

Tropic Levels

The first level of the energy pyramid is the producer's level which has 1,000 kcals, the second level is the primary consumers level which has 100 kcals, the next level is the secondary consumers which has 10 kcals, and then the last level is the tertiary consumers which has 1 kcal.

The shape

An energy pyramid is a pyramid because it shows how the kcals get lower and lower as you go up the pyramid.

Tertiary consumers/Producers

The producer section of the food pyramid is bigger because there are more plants than predators.

Chemical equation for photosynthesis


What is needed for photosynthesis

Photosynthesis needs sun, water, and carbon dioxide. Its waste is oxygen and it produces glucose.


The turning of all or part of an organism in a particular direction in response to an external stimulus. EX: Geotropism, Phototropism, Thigmatropism, Hydrotropism, etc.

Tropisms in the desert ecosystem

These tropisms help my ecosystem by allowing plants to get sunlight and water.


Decomposers are vital to my ecosystem because they break down nutrients from dead organisms and put the nutrients back into the soil. If we didn't have decomposers, all the dead organisms would pile up and every thing would start to die off.

Desert decompo

Some decomposers are worms, ants, and beetles.


The purpose of having adaptations is to help the organism to survive. They help organisms survive by giving organisms high heat resistance or going a long period of time without water.

Animals and plant adaptations

Some animal adaptations are high heat resistance, going long periods of time without water, etc. Plant adaptations are high heat resistance, going long periods of time without water, etc.

Effects of different environments

If you decided to put a cactus in an arctic environment, it would die faster because it wouldn't have high cold resistance and it wouldn't have enough water.

Natural selection

Natural selection is the gradual process by which heritable biological traits become either more or less common in a population as a function of the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. It is important because the old evolution of animals die off ,by predators or by natural causes, so the new evolution can take over.

Natural selection in organisms

For example dark colored lizards. Dark colored lizards (first generation) were easy to be picked off by birds so the population plummeted. Then light colored lizards (second generation) were not as easy to pick off so the dark colored lizards died off and the light colored lizards took over.

Comment Stream

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2 years ago

It could use more abiotic and biotic factors

2 years ago

Lol @aspenchristenson Need to be more specific on the abiotic factors D 😟

2 years ago
2 years ago

Be more specific but nice pics

2 years ago

Thanks @calstark

2 years ago

I recommend adding more biotic factors and being more specific with the abiotic factors.

2 years ago

You need to finish step 7, but I like the font of your headlines and how many you did.

2 years ago

good pictures

2 years ago

It's great, but the only advice I would give would be to add 3 spaces before each paragraph.

2 years ago

good job broseph