Ecology Chapters 3, 4 and 5. What is Ecology Interactions between living and nonliving things or the...

EcologyChapters 3, 4 and 5

What is Ecology

• Interactions between living and nonliving things or the biotic and abiotic.• Biotic – all living organisms (plants &

animals)• Abiotic – all nonliving things (rocks,

gases, minerals)

Biosphere – where all living and non living things are found (land, water, air)

Abiotic

Biotic

Biosphere• Different populations make up the

biosphere– Population – groups of

organisms of one species that live in the same place

• Populations use the same: food, water, mates, territory

– Different populations that interact make up Communities

• Examples: fish and alligators share the same territory (habitat) and interact with one another (predator/prey)

• All the interactions make up the Ecosystem

• Biomass is the total amount of living tissue in a given area

Levels of Organization

I. Biosphere – part of Earth that contains Life I. Ex. Air, water, land

II. Biome – group of ecosystems that have similar climate and dominant communities

I. Ex. Tropical rain forest, desert and tundra

III. Ecosystem – collection of all the organisms that live in a particular place along with all abiotic factors (nonliving)

I. Ex. Desert : cactus, snakes, rats, rocks, sand, ect…

IV. Community – different populations that live together in the same area

I. Ex. Forrest : Deer, owls, rabbits all live together

V. Population - Groups of individuals that live in same areaI. Ex. All the bullfrogs living in a lake

VI. Individual – one member of a species living in the populationI. One bullfrog

Interactions• Niche – role the organism plays in the environment.

Ex.: Bacteria decompose dead organic material• Autotrophs (producers) and Heterotrophs (consumer)

– Autotroph – use sunlight to make food/energy ex. – plants

– Heterotroph – consume producers and other heterotrophs for food/energy

• Herbivore –Consumer that eats only plant matter Ex. Cow

• Carnivore – Consumer that eats animals. There are two types: Predators which prey on live animals Ex. Lions, Tigers Scavengers which eat dead animals Ex. Vulture

• Omnivores eat both plants and animals Ex. Humans, Bears

• Decomposer – breakdown (eat) dead organic materials

Inter-dependence

• Symbiosis – living together. One organism depending on another for it’s survival. This is a Relationship all living things share.

• Types of Symbiosis– Mutualism – both organisms benefit Ex.: plants giving off O2

for animals and animals giving off CO2 for plants to use– Parasitism – one organism benefits and the other is harmed

Ex.: Tapeworm living in a persons intestine– Commensalism – one organism benefits and the other is not

affected Ex.: Birds nesting in trees

Energy cycle

• Energy constantly cycles through the ecosystem. Example: rabbit is born, rabbit lives a happy life, rabbit gets run over by car, vulture and coyotes eat remains and gain energy from food, bacteria decompose the rest of the living matter for energy.

• Models of Energy Cycles– Food Chain – Most simple model which shows how energy

flows from one organism to another. Only goes in one direction. Ex.: rabbit coyote bacteria

– Food Web – network of interconnected food chains. Shows more than one path energy flows through environment

– Trophic Levels – each organism represents a step in which there is a 10% gain and the rest of the energy is lost to heat

– Ecological pyramid – puts populations by numbers and energy level starting with producers at the bottom of the pyramid

Food WebEnergy flows through an ecosystem from producer to consumer and is eventually recycled by decomposers. Each living thing is dependant on the other living things in the community.

Ecological PyramidAt each level energy is lost in the form of heat. The greatest amount of available energy is found at the bottom level of the pyramid. Producers are the living things that have the most energy available to them.

Environmental Homeostasis

• Life is sustained by a balance of environmental factors and by maintaining a balance of nutrients that are necessary for living organisms. These are water, carbon and nitrogen. Each of these cycles through the environment such that the balance can be maintained.

Water CycleHow the environment maintains Homeostasis

Carbon Cycle How the environment maintains Homeostasis

Nitrogen Cycle How the environment maintains Homeostasis

Ecological Homeostasis

• Limiting factors are biotic and abiotic conditions that maintain balance in every community and keep populations from growing out of control– Availability of food– Temperature– Shelter– Availability of mates

• The Ways communities grow into new niches is called Succession

- Primary Succession – colonization of new environments (ex. islands)

- Secondary Succession – usually happens after natural disasters or other major changes to the environment

Biomes

• The Major Biomes– Tropical Rain Forest– Savanna – Desert– Grassland– Tundra – Temperate Forests and Grasslands – Mountains– Temperate and Coniferous Forest– Freshwater and Saltwater Aquatic

Population Dynamics

• Population Growth is limited by certain factors– Space available– Food– Competition for resources between different species– Number of mates– Natural disaster– Disease– Temperature

• Each ecosystem has a carrying capacity. This means the area can only support a certain number of each species due to the limiting factors for populations

Human Populations

• Factors affecting Human Population growth– Birth rate and Death rate

• Birth rate – Death rate = population growth rate

– Fertility• When fertility is high populations increase

– Population Age• Very young / immature pre-reproductive• Reproductive mature ( only ones that can

increase population )• Post-reproductive / very old

– Mobility• Immigration – movement into a population• Emigration – movement out of a population