Ecology The study of ecosystems

Environments Almost anywhere/everywhere is an environment to at least some sort of organism. Ie: urban, rainforest, polar, grasslands, mountains, oceans, freshwater lakes, deserts, everglades, rivers/streams, your body, etc… Human Microbiome

Ecosystems Every living organism on earth lives in an ecosystem – The living and nonliving things in one place. Non-living factors vs living factors – Abiotic vs biotic – Abiotic factors are the nonliving parts of an ecosystem. The types and amounts of abiotic factors determine the organisms that live there

5 important abiotic factors Water – All organisms need water to survive. Some need more than others. Light – Plant life obviously needs light to photosynthesize. Temperature – Generally, more sunlight means warmer temperatures. Atmosphere – An atmosphere is a mix of gases surrounding a planet. What gases surround our planet? (next slide) Soil – Contains different amounts of nutrients, minerals and rock. Remember why venus fly trap needs to eat flies? – They grow in nutrient poor soil Jaws of death

78% 21% 0.93% 0.034%

A climate minute Global warming Hank Green

Biotic Factors “All of the living or once-living things in an ecosystem.” They are categorized into the following: – Communities are the living parts of an ecosystem that live and interact with each other. – Populations- Group of organisms of the same species that live together. – Biomes- geographic area on earth that contains ecosystems with similar biotic and abiotic features.

Name some different ecosystems found within the ecosystem (not in notes)

Community (not in notes)

Populations (not in notes)

Factors that affect health of populations Population size – Can increase or decrease depending on lots of different circumstances. Like what? Population density – This describes the number of organisms in the population relative to the amount of space available. – Lets figure out the population density of our classroom. How many cubic feet does each of us have?

Limiting factors Limiting factors are factors that can limit the growth of a population. – Lets think of some: Available water Space Shelter Food Predation Competition disease

Carrying capacity of an ecosystem Many times populations will reach their carrying capacity. – Largest number of individuals of one species that an ecosystem can support over time.

Food chain/food web All living and nonliving things in an ecosystem are interconnected Think of an environment as a spider web. – When one thread is disturbed, the entire web is disturbed. – If a thread is cut, the web might still work but is weakened. GMO mosquitos

Keystone species Species that plays a crucial role in an ecosystem. Without it, the ecosystem could change dramatically. Examples: – Beavers: Beavers are considered habitat engineers because they change the environment by building dams. This dam building provides still water in which many species flourish. – Bees: By pollinating plants, bees contribute to their survival. The plants are shelter for insects, which are then eaten by other species, like birds. – Hummingbirds: Pollination is the reason hummingbirds are a keystone species. In places where the numbers of hummingbirds are low, other species of plants will take over the ecosystem. – Sugar maple: This tree is a keystone species of the hardwood forest. It brings water from lower levels in the ground that helps other plants. It is also home to many insects, birds, and small animals.

How do all these organisms obtain energy? Starts with the sun – Why do we absolutely positively NEED the sun? Remember the 3 different types or organisms that indicate how they obtain energy?

Organisms are either… Producers Consumers Decomposers

Producers Can make their own food – photosynthesis Source of all the food in an ecosystem All organisms that cannot make their own food ultimately depend on producers

An organism that feeds directly or indirectly on producers. – Ie; grasshoppers and rabbits are plant eaters Herbivores – Shark, snake, and wolves eat other animals. Carnivores – Crows, bears, and humans eat both omnivores Consumers

Decomposers After living things die, decomposers use the dead matter as food Break down dead organisms into simpler substances (kind of like our stomachs, so that the nutrients can be absorbed in our small intestines) In return, they return important materials back to the earth (fertilizers) “natures recyclers”