Download Unit 6 Ecology Ecology – How organisms interact with both living

Unit 6
Ecology
Ecology – How organisms interact with both living and non-living things in the environment.
Environment – All living & non-living things that surround an organism (weather, food, water, predators)
Ecosystem (Ecological system) - Any PART of the environment.
• Biotic factors – all living things in environment (plants, bacteria, animals)
• Abiotic factors – all non living things in environment (water, soil, energy, space, air, light)
Habitat – Place where a plant or animal lives (forest, oceans, streams, fields)
Population – all organisms of a particular species in the same area.
Community – All the different populations in the same area.
Biosphere – All of the Earth’s Ecosystems (Land, Air, Water)
ALL LIVING ORGANISMS ARE INTERDEPENDENT (linked with each others).
ENVIRONMENTAL LIMITS ON POPULATIONS
Population size depends on available resources (air, sun, space, food, water)
• Competition – the struggle for resources among organisms.
Factors That Limit Population Size
Biotic:
PREDATOR vs. PREY - As predator population rises, prey population declines. Eventually, predator population declines, allowin
population to recover and grow. (Equilibrium).
Abiotic:
Amount of O2 in pond limits fish population.
Amount of Sunlight, water & temperature limits plant growth.
Carrying capacity – The number of organisms an ecosystem can support.
• Determined by available resources and the interactions of organisms.
Population interactions occur mostly during competition for food and resources.
• Diversity is essential in ecosystems since all populations are linked directly or indirectly.
Ecological niche – The role or part of the ecosystem a species occupies.
• only one or two species can occupy a niche
• Competiton and the species best suited will occupy the particular niche.
• Sometimes foreign species overrun native species due to lack of natural predators.
Relationships in an Ecosystem– Are either COMPETITVE or COOPERATIVE.
Food Chains – illustrates predator-prey relationship or What Eats What from Bottom to Top.
Organisms are defined on how they obtain food:
Autotrophs – (Producers) Mostly Plants which are the source of food for most.
Heterotrophs – (Consumers) Mostly Animals that eat other living things.
• Herbivores – Eat plants
• Carnivores – Eat Animals.
Decomposers – Consumes and BREAKS DOWN waste and dead bodies Substances decomposed get recycled in soil and
reused by Autotrophs. (Ex) Bacteria breaksdown organic material, providing nutrients to soil.
Parasites – Live ON and OFF other living thing organisms (hosts). (ex) Ticks (parasite) on Dogs (host).
In a Food Chain – Light energy passes from Sun to plants –animals – decomposers –soil and back to plants.
FOOD WEB – Shows complex, multiple feeding relationships between organisms.
• Organisms that have multiple food sources help keep ecosystem in balance.
• Rotating to other food sources give declining food sources time to recover.
ENERGY FLOW THROUGH THE ECOSYSTEM
Solar Energy stored in food is gradually lost through the food chain.
• Most of the energy is used to sustain life.
Energy Pyramid – Diagram that shows transfer of food through the food chain/web.
Carnivore ------------>
======
< ---------------
Herbivore ------------>
==============
< ---------------
Producer ------------->
Bird
Caterpillar
====================== <---------------- Oak Tree
RECYCLING / REUSING MATERIALS
Decomposition – Process of breaking down dead organisms & wastes from living organisms.
(ex) Bacteria and Fungi return materials to the environment.
Carbon, Hydrogen, Oxygen and Nitrogen are released by decomposers and return to the environment.
(ex) - Plants trap CO2 & H2O in starch during Photosynthesis.
- Some starch is used to maintain plant life or is eaten by other organisms.
- The waste products or death of organisms allows decomposer to release these elements back into
the environment for reuse.
DIVERSITY BENEFITS SPECIES AND HABITATS
Biodiversity - Measures the degree of different species within an ecosystem.
• Diversity in ecosystem slows down disease (different tree species can resist attacks by particular insects/fungus)
• Allows for rotation of predator – prey relationship which helps keep populations stable over time.
• Natural disasters or Human actions may cause overpopulation imbalance or loss of species.
(ex) Wipe out wolves, Deer population increases. Farmers Plant ONE type of crop and can lose it all.
Diversity in rainforest provides medicines, insecticides and other resources. Losing species means losing possible
Valuable resources.
ENVIRONMENTAL CHANGES
Ecological Succession - Series of changes by which one habitat changes into another. (ex) Pond ---> Forest
• Climate changes, natural disaster or animal/Human activity can change the environment.
(ex) Floods, fire, drought, new construction, new species.
A change in Habitat usually means a change in organism that inhabits it.
Two Common Ecological Succession
Rocky Habitat -----> Rocks weather, soils accumulate, vegetation grows-----> Forest
Lake / Pond ------> Soil accumulation, deposition, fill in pond-----> Forest