8.L.3.1Messana

Science 8

Dynamic – change & vary over time Biodiversity is looked at to indicate health

A complex, interactive system that includes:◦1. Biotic components (living) Exs: bacteria, fungi, plants, animals

◦2. Abiotic components (nonliving, physical or chemical) Exs: water, oxygen, nitrogen, salinity, pH,

soil nutrients & composition, temperature, amount of sunlight, precipitation

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

Ecosystem = communities of organisms & their abiotic factors living together, sustained by the continuous flow of energy

Biosphere = all ecosystems on Earth

Population #s fluctuate at a predictable rate

Supply of resources fluctuates at a predictable rate

Energy flows through at a fairly constant rate

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!

What is Reginald’s habitat?

What is Reginald’s niche?

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)

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 Factors 4. Abiotic Factors

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

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

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

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

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

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

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

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

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?

How does this relationship help maintain balance & stability in an ecosystem?

Let’s Find Out…Animal Fight Club – What are they fighting

for?http://www.animalfightclub.com/

How does this relationship help maintain balance & stability in an ecosystem?

Let’s Find Out…Elephants Show Cooperation on Testhttp://www.youtube.com/watch?

v=CXcRw6Piaj8

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

• 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?