Ecosystems & Their Components

1. Ecosystems & Their Components 8.L.3.1 Messana Science 8

2. Ecosystem: • Dynamic– change & vary over time • Biodiversityis looked at to indicate health • A complex, interactive system that includes: • 1. Biotic components (living) • Exs: bacteria, fungi, plants, animals • 2.Abioticcomponents (nonliving, physical or chemical) • Exs: water, oxygen, nitrogen, salinity, pH, soil nutrients & composition, temperature, amount of sunlight, precipitation

3. Hierarchy • Species = same organisms that can breed with each other • Populations = small group of same species in the same location/geographic area • Communities= different populations that interact together within a certain area

4. Hierarchy • Ecosystem= communities of organisms & their abioticfactors living together, sustained by the continuous flow of energy • Biosphere = all ecosystems on Earth

6. Stable ecosystem • Population #s fluctuate at a predictable rate • Supply of resources fluctuates at a predictable rate • Energy flows through at a fairly constant rate

7. Within an ecosystem, each species has a… • Habitat: the place where an organism lives. It supplies all the biotic and abiotic factors the organism needs to survive. • Niche: an organism’s role/”job.” what it eats, how it eats and what eats it… If the niche of one organism overlaps the niche of another organism, you have competition!

8. Reginald http://www.youtube.com/watch?v=2L6N2diE8jc • What is Reginald’s habitat? • What is Reginald’s niche?

9. Population Density • Measures the # of individual organisms living in a defined space • Carrying Capacity = the # of individuals that an environment can support • Limiting Factors = things that can change within an ecosystem and will regulate/change a population (its size, density, distribution)

10. Population Density Factors • 1. Density-Dependent Factors: • Affect a large population more strongly than small • Triggered by density (crowding) • Ex: Competition for food, shelter, territory, or mates; predation, parasitism, disease • 2. Density-Independent Factors: • Occur regardless of how large the population is • Reduce size of all populations in area by same %age • Ex: Weather changes, human activity – pollution, natural disasters (fires/floods), drought • 3.Biotic Factors4. Abiotic Factors

11. Interactions in an Ecosystem • Predation = an interaction between species in which one species eats the other • Predator eats the Prey!! • Ex: Whale Shark eats plankton and small fish • Ex: Red wolf eats deer, swamp rabbits, etc

12. Interactions in an Ecosystem • As prey population increases, predator population increases (more food available) • As predator population increases, prey population decreases (prey are easier to find, more get eaten) • Predator-prey density fluctuates in a predictable cycle  stable ecosystem

13. Interactions in an Ecosystem • Competition = occurs when 2 or more organisms need the same resource at the same time (food, shelter, water) • Can be among members of same or different species • Occurs when organisms share same niche • Ex: Hawks and fox eat mice • Results in decrease in population of species that is less adapted to compete

14. Interactions in an Ecosystem • Symbiotic Relationships: • Between organisms of 2 different species that live together in direct contact • Fluctuations in populations of 1 species will affect the other • 1.Parasitism • 2.Mutualism • 3. Commensalism

15. Interactions in an Ecosystem • Parasitism = symbiotic relationship where one organism (the parasite) benefits at the expense of the other organism (the host) • Usually parasite does not kill host • Some parasite live within host – tapeworms • Some parasites feed on external surface of host – fleas, aphids • Ex: Mosquito sucking blood from animals

16. Interactions in an Ecosystem • Mutualism = symbiotic relationship in which both organisms benefit & they help each other to survive • Ex: plant roots provide food for fungi that break down nutrients the plant needs • Ex: bacteria can digest wood and live in digestive tracts of termites • Oxpecker Bird eats ticks and parasites, mammal gets pest control

17. Mutualism • Remora sharks have an adhesive disk on their dorsal surface, with the help of which they attach themselves to whales and then, clean the whale’s skin and feed on the remains from the whale's food

18. Interactions in an Ecosystem • Commensalism = symbiotic relationship where one organism benefits and the other is not affected positively or negatively • Glass shrimp, which are almost completely see through, will attach to the chocolate chip sea star and take on its coloration. This helps the shrimp camouflage itself so it is not eaten by predators

19. “Oh Deer” Conclusion Questions: • 1. What are the essential components of a habitat? • 2. What are some of the “limiting factors” that affect an organism’s survival? • 3. Are wildlife populations static, or do they tend to fluctuate, as part of an overall “balance of nature”? Explain your answer. • 4. Is nature ever really in “balance” or are ecological systems involved in a process of constant change?

20. Field Trip • You will be going outside IN AN ORDERLY AND QUIET MANNER. • Describe the school ecosystem • What types of communities do you see? • What populations of organisms do you see? • For three organisms, describe the habitat and niche of each organism

21. Think About It… • What do all living organisms need? • How might organisms in an ecosystem interact? • What factors would influence the size of a population? Do you think there is a limit to the size of a population in an ecosystem? Explain. EQ: How do different factors in an ecosystem affect a population?