Biotic factors are living factors in an ecosystem
Tarantula Saguaro Cactus
Rattlesnake Prickly Pear Cactus
Coyote Cholla Cactus
Abiotic Factors are non-living factors in an ecosystem
Carrying Capacity and Changes in Populations
Carrying Capacity is the largest number of individuals of one species that an environment can support. A habitat needs food, water, shelter, and space for organisms to survive. For example, a change in the community could be that the mouse population could decrease causing lots of snakes to die off, but once the snakes die off more mice would live and the population would go back up. Another example is that Mexican Wolves eat Bighorn Sheep, but if the sheep population goes down then the wolves will die off.
Limiting Factors is any factor or condition that limits the growth of a population in an ecosystem
Examples: Minimal water, extremely high temperatures, unbalanced predator/prey relationships, etc.
Snakes eat mice, but if the mice don't get enough water or they over heat and die then the snake population would decrease. Or if snakes don't get the food they need, they would die and the mice population would increase.
Energy Roles are determined by how the organism gains energy and how it interacts with other living things in its ecosystem
There are 3 main types of energy roles: Producers, Consumers, and Decomposers.
The producer provides the energy that the rest of the organisms in the ecosystem need.
Plants(producer) get their energy from the sun,the rabbit and mouse(1st consumer) get their energy from the plant, the snake and hawk(2nd consumer) get their energy from the rabbit and mouse, and the bacteria(decomposer) get it's energy from the dead organisms.
Food Chains and Food Webs
Food webs are more realistic because they show more opportunities than food chains. For example, the large lizards eat both insects and small lizards, also hawks eat large lizards, Kangaroo rats, and snakes.
If you remove insects, the scorpions would have nothing to eat and they eventually will die off. Also, the large lizards will only be able to survive off small lizards causing their population to go down.
Trophic Levels and Energy Pyramids
A pyramid shows how the amount of energy decreases each trophic level opposed to a square that doesn't have a decrease in size as you move up to show the energy decreasing.
The base of the pyramid, where the producers are, has approximately 10,000 kcals. The second trophic level has approximately 1,000 kcals. The third trophic level has approximately 100 kcals. The fourth trophic level has approximately 10 kcals.
Producers get the most energy passed to them through the sun, but the top predators have the least because each level decreases by 10% and at the very top there is barely any energy left.
In order for photosynthesis to happen there must be water, carbon dioxide, sunlight, and chlorophyll. Photosynthesis produces glucose, oxygen, and water. Photosynthesis takes place inside plant cells in chloroplasts.
Tropisms is the turning of all or part of an organism in a particular direction in response to an external stimulus.
Depending on where the sun hits the plant it will bend towards it which is good if there's a lot of cactus together it will grow in its own place where it will get a lot of sun of its own. In the desert, the most common type of tropism is hydrotropism, where the plants roots grow down to their source of water.
The Role of Decomposers
Decomposers are vital to all ecosystems, but that's not important. What is important is that if decomposers were not around we would be living in filth. In the desert decomposers break down the waste of dead animals. If the decomposers didn't exist, then the desert would smell rotten and be filled with dead animals and waste. Some desert decomposers are soil bacteria, fungi, worms, mushrooms, dung beetles, termites, and ants.
Adaptations are important to all organisms to stay alive. They help them survive from predators also known as camouflage, they help them survive from heat also known as crepuscular, they help them store water so they don't dry out also known as forming uric acid.
If you were to remove the Kangaroo Rat from the desert and put it somewhere else where the surroundings were a light color they would die off. Another example, if you put it in a non-sandy habitat it wouldn't be able to blind its predator by kicking sand into there eyes causing them to die off.
Natural selection is the process of adaptations in a species over time from changes in their environment. Natural selection is how adaptations happen in a species. They help species survive and reproduce.
The rock pocket mouse is one example of natural selection. Some fur coats are light to match the sand, but some are dark to match the dark rocks. The population changed when the light mouses living on the rocks changed over time to dark mouses.It changes because of a genetic mutation which can be both bad and good. The population changes in response to the sand and rocks.