1. Ecosystems & Energy Flow (4.1-4.2)
Could we live on the Moon? On Mars? In this scene from “The Martian,” Matt Damon solves one major problem: how to grow food on Mars. What would we need to live in these inhospitable places?

2. 4.1
Essential idea: The continued survival of living organisms including humans depends on sustainable communities.

3. Ecology Population Ecosystem Community Species Habitat
4.1.U1 Species are groups of organisms that can potentially interbreed to produce fertile offspring. AND 4.1.U7 A community is formed by populations of different species living together and interacting with each other. AND 4.1U8 A community forms an ecosystem by interacting with the abiotic environment.
Ecology
The study of relationships between living organisms and between organisms and their environment
Population
A group of organisms of the same species living in the same area at the same time
Ecosystem
A community and its abiotic environment
non-living
Community
A group of populations living and interacting with each other in an area
Species
A group of organisms that can interbreed to produce fertile offspring
Habitat
The environment in which a species normally lives (the location of a living organism)

4. Levels of Organization
Biome
Ecosystem
Community
Population
Organism

5. Populations may become isolated from each other
4.1.U2 Members of a species may be reproductively isolated in separate populations.
Populations may become isolated from each other
The may be separated geographically
Over time, they may evolve to look or behave differently or sing a slightly different song
If those populations are reunited and do not interbreed, then they are reproductively isolated
Harris’s antelope squirrel inhabits the canyon’s south rim (L). Just a few miles away on the north rim (R) lives the closely related white-tailed antelope squirrel

6. 4.1.U3 Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods). AND 4.1.U4 Consumers are heterotrophs that feed on living organisms by ingestion.

7. 4.1.U9 Autotrophs obtain inorganic nutrients from the abiotic environment
Convert solar energy into organic molecules (food) and become the base of the food chain
They obtain the nutrients they need from the abiotic environment – ex. Carbon & nitrogen

8. Detritivore Ingests non-living organic matter
4.1.U5 Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.
Detritivore
Ingests non-living organic matter
Ingest first, then digest
Examples:
Earthworms ingest dead matter
Larvae of dung beetles feed by ingestion of feces rolled into a ball by their parent

9. Digest first, then absorb
4.1.U6 Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion
Saprotrophs
Live in or on non-living organic matter, secreting digestive enzymes into it and absorbing digestive products
Digest first, then absorb
Also known as decomposers because they break down carbon compounds in dead organic matter and return elements back into the ecosystem.
Examples:
Bacteria
Fungi

10. 4.1.S1 Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition

11. 4.1.S1 Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition

12. 4.1.S1 Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition

13. 4.1.S1 Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition

14. 4.1.S1 Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition

15. Chemical elements are in limited supply on Earth
4.1.U10 The supply of inorganic nutrients is maintained by nutrient cycling.
Chemical elements are in limited supply on Earth
Why do they not run out?
They are recycled!
Often it is not as simple as the element being incorporated into an organisms cells and then returned to the environment.
It usually passes from the environment to an organism to another and then another before being returned to the ecosystem by decomposers.

16. 3 requirements for sustainability in ecosystems: Nutrient availability
4.1.U11 Ecosystems have the potential to be sustainable over long periods of time.
Ecosystems have the potential to be sustainable over long periods of time
Sustainability has become a hot topic because our use of some resources are unsustainable.
When something is used quicker than it is replaced then it is unsustainable. Example: Fossil fuels
3 requirements for sustainability in ecosystems:
Nutrient availability
Detoxification of waster products
Energy availability

17. Back to the picture on the first slide…
4.1.U11 Ecosystems have the potential to be sustainable over long periods of time.
Ecosystems have the potential to be sustainable over long periods of time
Nutrients can be recycled indefinitely
Waste from one species can be exploited as a resource by another
Example: Urine and feces contain nitrogen compounds and farmers often put animal manure on fields to grow crops. Plants need nitrogen to form DNA and protein
- Energy cannot be recycled. Most energy is supplied by the sun.
Back to the picture on the first slide…
How did Matt Damon get the plants to grow on Mars???

18. Mesocosms
Small, closed-off experimental systems set up as ecological experiments
Can be used to test effects of varying certain conditions on ecosystem stability as well as the sustainability of ecosystems