Ecology Objectives: To understand ecological levels of organization. To describe the flow of energy through an ecosystem. To describe and analyze the components.

Ecology

Objectives:• To understand ecological levels of organization.• To describe the flow of energy through an

ecosystem.• To describe and analyze the components of the

water, carbon, nitrogen and phosphorous cycles.• To identify the effects that destruction of

habitats, pollution, urbanization, and natural disasters have on population.

What is ecology?

• The scientific study of relationships between organisms and their environment.

• It explains how living organisms affect each other and the world they live in.

Why is ecology important?

• Allows us to understand how the natural world around us works

• Allows us to understand how organisms (plants & animals) are shaped by their surroundings (environment)

• Ex. O2 in atmosphere from photosynthesis.

Ecology Issues Today

• Exploding Human Population

• 6 billion people in 1996

• 7.8-12.5 billion people by the year 2050

• Greater Earth resources necessary to support humans

• Food, space, energy

The Sixth Mass Extinction

• Human impact has destroyed the habitats of many bird species.

• Hawaii, 60 species now extinct

The Thinning Ozone Layer

• Ozone layer protects Earth’s living organisms by absorbing UV radiation.

• Hole: low ozone level over Antarctica

• Sunburns and skin cancer

Climatic Changes

• Greenhouse Effect: gases in the atmosphere trap heat emitted from the Earth’s surface, insulating and warming the Earth

• Burning fossil fuels releases gases that trap heat in the atmosphere. (carbon dioxide, methane, & nitrous oxide) As these gases build up, they trap more heat near the Earth’s surface, causing Earth’s climate to become warmer than it would naturally.

Interconnectedness

• Key Theme: All organisms affect and are affected by the living and non-living components of their environment

• The next slide shows different species that are ecologically connected. Describe some ways they are connected.

How is the environment organized?

• The parts of an environment are organized into two categories:

1. Abiotic Factors

2. Biotic Factors

Nonliving Environment

• Abiotic Factors (A=“not” Bio= “living”)– the nonliving parts of an organism’s environment (physical and chemical)

• Abiotic factors affect an organism’s life

• Examples:

• Soil, temperature, pH, sunlight

• Precipitation, air currents, and humidity

Living Environment

• Biotic Factors: All the living parts of an environment

• All organisms depend on others, directly or indirectly, for food, shelter, reproduction, or protection.

• Examples: competitors, decomposers, and predators

Biotic or Abiotic?

• Abiotic

Biotic or Abiotic?

Biotic

Biotic or Abiotic?

Abiotic

Biotic or Abiotic?

Biotic

*Calcium

*Nitrogen

Potassium

*Sulfur

*Phosphorus

Biotic Factors? Abiotic Factors?

Bacteria live on these roots!

• Bacteria get carbohydrates

• Plants get the nitrogen they need to grow

• These two organisms depend on each other for survival

Levels of Organization

• Now that you can identify biotic and abiotic factors, we will organize their interactions at different levels

• Ecologists have arranged an organism’s interactions into different levels according to complexity.

Levels of Organization

1st Level: Organism

• The simplest level in ecological organization

• An organism is an individual living thing.

• Bacterial cell or elephant• Scientists study the

adaptations that allow organisms to overcome challenges of their environment

2nd Level: Population

• A group of organisms, all the same species, which interbreed and live in the same place at the same time

• Scientists study the members of a single species; how they share their environment. (Food, water, etc.)

3rd Level: Community

• Biological Community is made up of all the populations of different species that live in the same place at the same time; all biotic factors

• Here: zebras and wildebeest

• Scientists study how the species interact

4th Level: Ecosystem

• All the biotic and abiotic parts of an environment found in a particular place.

• Populations of plants and animals that interact with each other in the same place and the abiotic factors of that area.

Ecosystem

• Two Types:

1. Terrestrial (Land)

2. Aquatic (Water)

a. Freshwater (lakes, ponds, rivers)

b. Saltwater/Marine (oceans)

5th Level: Biosphere

• The portion of Earth that supports life (13 mi. thick)

• Life is found in air, on land, and in fresh and salt water

• If the Earth were the size of an apple, the biosphere would be as thick as the apple’s skin.

Which Level?

• Organism

Which Level?

• Community

Which Level?

Population

Within an ecosystem

• Species share a habitat (the place where and organism lives out its life), food and shelter

• Niche: the way of life of a species; the role a species plays in its environment.

• Includes all biotic and abiotic interactions • How a species meets its needs for

– Food and shelter– Survival and reproduction

Sharing a habitat

• pH, other chemical factors determines what lives here. Amount of sunlight – source of energy

• Insects and fish eat plants; turtles eat fish; birds eat insects

Fish, turtles, plants, insects, and birds

Niche

• All of these finches have different sized/shaped beaks.

• Different ecological niches

Habitat & Niche

The habitat is the organism's "address" and the niche is its "profession“

Oak Tree?

Predators and Prey

• Predators – seek out and eat other organisms

• Prey – organisms that are eaten

• Examples?

CAUGHT!

Predation

• Influences where and how a species lives

• Effective way to regulate population

• Predation Defenses: schools of fish, color, odor

Energy Transfer

• All organisms need energy to grow, move and reproduce

• In an ecosystem, the ultimate source of energy comes from the sun

• Plants use that energy to make it’s own food, and then other organisms eat those plants to get energy.

Producers

• Organisms that make their own food are called autotrophs

• Photosynthetic – using the sun to power food production

• Examples?

• Plants, some kinds of bacteria, protists (plant-like algae)

Biomass

• The total amount of living matter in a certain area (habitat).

• Measured in g/m^2

Biomass Pyramid:

Consumers

• Heterotrophs – organisms that cannot make their own food

Primary Consumer Eats plant material

(Rabbits, Cows)

Secondary Consumer Eat primary consumers (Foxes, Hawks, Snakes)

Tertiary Consumers Eat secondary consumers (Wolves, Bears, Humans)

Herbivores

• Eat producers (plants)• Zebra that eat grass

is an herbivore• Grasshopper• Caterpillars

Carnivores

• Eat other consumers• Lions eat zebra• Praying mantis eats

grasshoppers

Omnivores

• Eat both producers and other consumers

• Bears eat berries from a plant (producer) and also fish

Detritivores

• Feed on the “Garbage” of the ecosystem

• Ex. Fallen leaves and branches, dead organisms

• Vultures

Decomposers

• Break down dead tissues (decay)

• Decay “recycles” nutrients

How Energy flows through an ecosystem

• 1st Step Producers• 2nd Step Primary

Consumers that eat producers

• 3rd Step Secondary Consumers that eat other consumers

• 4th Step Tertiary Consumers that eat secondary consumers

Figure 19.26

Tertiary consumers

Secondary consumers

Primary consumers

Producers

10 kcal

100 kcal

1,000 kcal

10,000 kcal

What happens to energy as you go up trophic levels? Why?