ECOLOGY

What is Ecology? Ecology- the study of interactions between organisms and their environments All environments contain: Biotic factors – any living thing (food source, predators) Abiotic factors – nonliving things (temp, pH, soil, water)

Organism – 1 individual Population – group of the same species Community – interacting populations of different species (living) Biosphere – all parts of planet Earth that support life Ecosystem – ALL living (biotic) and nonliving (abiotic) things in an area Levels of studying ecology:

From organism to the Biosphere

Population Growth “Exponential Growth” Starts out as slow growth and then rapidly increases. This is what happens if there are no “limiting factors” on the population (things that restrict or slow growth). “J-shaped” curve

Population Growth “Logistic Growth” How population growth usually works in the world. Carrying capacity is the number of individuals in a population that an ecosystem can support. Extinction is when all the individuals in a population have died out.

Species Interaction Symbiosis is a close and permanent relationship between organisms of two different species Types of Interactions: 1. Mutualism – both species benefit 2. Commensalism – one species benefits, the other is unaffected 3. Parasitism – one species benefits, but the other is harmed 4. Predation – one species attacks and kills another for food

SOL Practice!

Species Interaction Card Sort!

How big is 1 billion? If you count one number per second and do not stop for breaks or sleep, it will take you 31.7 years to reach 1 billion! It would take us 221 years (7 x 31.7years = 221) to count to 7 billion. One billion minutes ago was about 100 A.D. One million = 1,000,000 One billion = 1,000,000,000

Part 1: Birth Rates, Death rates, and Calculating Population Growth

Part 2: Positive + Negative Growth

Energy flow in an ecosystem Energy for life on Earth starts with the sun. Producers (autotrophs) convert the sun’s energy. Consumers (heterotrophs) eat the producers. Decomposers (“detritovores”) recycle nutrients of dead organisms. Direction of the arrows show how energy flows from one organism to another.

Food Chain vs. Food Web Producer Primary (1 st ) Consumer Secondary (2 nd ) Consumer Tertiary (3 rd ) Consumer

SOL Practice

Energy flow in an ecosystem Trophic level – each step in the food chain or web Energy pyramid – shows how much of sun’s original energy is available at each trophic level.

Energy Pyramid Of all the energy available in an ecosystem, only 10% is passed from one trophic level to the next. The other 90% is used by the organisms to grow and maintain homeostasis or is lost as heat!

Nutrients/elements must cycle so that all organisms can use them (remember CHONPS). 3 cycles to investigate: 1. Water cycle 2. Carbon cycle 3. Nitrogen cycle Nutrient Cycles in an ecosystem

Hydrologic (water) Cycle = water evaporates from leaves

Carbon Cycle

Atmospheric nitrogen (N 2 ) makes up nearly 78%-80% of the atmosphere. Organisms cannot use it in that form. Bacteria in the soil convert nitrogen into a form organisms can use. Nitrogen Cycle The atmosphere of Earth

Bacteria in soil Soil bacteria N 2 in atmosphere

Ecological Succession Ecological succession is a predictable change in the sequence (order) of species in an ecosystem. Takes hundreds of years! Succession occurs until a climax community is reached, which is a stable group of populations living together. ***In most of Virginia, the climax community is a deciduous Oak- Hickory forest. Does this look familiar to you?

Primary Succession – “start from scratch” Primary succession is when a brand new ecosystem is formed on a bare layer of rock.

Secondary Succession – after a disaster Secondary succession occurs after a major change in an ecosystem (ex. natural disaster or human activities)

SOL Practice!