What is an ecosystem? Ecosystems have biotic and abiotic components working together in a system.
The APsolute Recap: Biology Edition - Biodiversity
What is an ecosystem? Ecosystems have biotic and abiotic components working together in a system (0:54). The more diverse an ecosystem is, the more resilient it is during environmental changes. (1:27) Both biotic and abiotic factors play a role in maintaining species diversity and the keystone species is the lynch pin. (2:13)
The Question of the Day asks (6:35) Approximately how much energy is transferred from one trophic level to the next?
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Hi and welcome to the APsolute Recap: Biology Edition. Today’s episode will recap Biodiversity
Zoom out:
Unit 8 - Ecology
Topic 8.6
Big idea - Systems Interactions
Don’t worry - we will lay the oil pipeline right across this migration pathway and there will be no effect on the caribou population. Yeah right! A cause without an effect? Seems unlikely. So it is with ecosystems too - each organism and drop of rain impacts everything it touches in the environment.
Let’s Zoom in:
First off - what is an ecosystem? An ecosystem is a community of organisms and nonliving components working together as a system. Like all machines, it consists of specific parts that have certain roles. Consider the bike, made of rubber tires, aluminum frame, tubing, maybe a metal bell? But forget the bike chain, and you’re not going to get very far. Ecosystems function similarly, with biotic and abiotic intertwined and hopefully, in balance.
Generally speaking, the more diverse an ecosystem is, the more resilient it is to environmental change. Even the slightest change in Alaska may impact harbor seals whereas a change in the tropics may go unnoticed by the mosquito. This correlation is found both in the natural world and in artificial ecosystems made by humans, like parks or gardens. Ecosystem organization is influenced by species diversity. When I say organization, I’m referring to the quantity and type of producers, and subsequent levels of consumers. And if it has greater diversity, it is less likely to be upended by organisms that enter or leave the area through immigration or emigration.
Ok so let’s say an ecosystem is diverse - will it always stay that way? Somewhat of a trick question, since the environment is always changing and living things along with it. However, both abiotic and biotic factors can help to maintain ecosystem diversity. Remember that abiotic factors are nonliving components, like sunlight, water and wind whereas biotic factors include all organisms. For example, if there is more water available in an area, then more plant and animal species can utilize that water as a resource. This correlation also holds true with resources like soil nutrients and available sunlight. On the biotic side, both producers and consumers help maintain ecosystem diversity. Many plants form the foundation of trophic levels and provide shelter for other organisms, like insects and birds. Their roots can also reduce erosion which maintains soil richness for other species to thrive. Additionally, secondary and tertiary consumers eat a variety of prey and help to keep those populations within sustainable range. If primary consumers had a population boom, they might deplete too many producers from the ecosystem.
And then there's that one organism, the one with the gold star, the one that the entire ecosystem hangs their hat on - the keystone species. A keystone species is one that the community's entire structure depends on. Like that last jenga piece - you just know that if you remove it, the entire tower will fall. There may not be many members of the keystone population, but their effect can be much greater. For example, the wolf is a keystone species in certain forests - keeping prey populations in check and by proxy, making more resources available to other organisms. And it's not just predatory behavior that makes a keystone population valuable - sometimes it's what they leave behind! The African elephant carves the landscape as it feeds, burrows watering holes, and even leaves droppings for the dung beetle to call home. If you remove a keystone species, the entire community may collapse.
Time for unit connections. We have a connection to Unit 7 - natural selection with the coevolution of predator and prey. How fast does the antelope have to be? Not faster than the lion, just faster than the next slowest antelope. Alright - what about the exam? This unit is a great opportunity to practice science skill 6 - argumentation. You may need to predict the causes or effects of a change to the system. Maybe an invasive species makes itself known? Often you will need to extract data from graphs or ecosystem diagrams in these questions.
To recap……
Ecosystems are biotic and abiotic components working together in a system. The more diverse an ecosystem is, the more resilient it is during environmental changes. Both biotic and abiotic factors play a role in maintaining species diversity and the keystone species is the lynch pin.
Coming up next on the Apsolute RecAP Biology Edition: Community Ecology
Today’s question of the day is about energy.
Question of the day: Approximately how much energy is transferred from one trophic level to the next?