Hank gives the rundown on the top five ways humans are negatively impacting the environment and having detrimental effects on the valuable ecosystem services which a healthy biosphere provides.

Chapters:
Ecosystem Services
The Importance of Biodiversity
Deforestation
Desertification
Global Warming
Invasive Species
Overharvesting

Interactions between species are what define ecological communities, and community ecology studies these interactions anywhere they take place. Although interspecies interactions are mostly competitive, competition is pretty dangerous, so a lot of interactions are actually about side-stepping direct competition and instead finding ways to divvy up resources to let species get along. Feel the love?

Chapters:
1) Competitive Exclusion Principle
2) Fundamental vs. Realized Niche
3) Eco-lography / Resource Partitioning
4) Character Displacement
5) Mutualism
6) Commensalism

Hank gets to the more violent part of community ecology by describing predation and the many ways prey organisms have developed to avoid it.

Chapters:
Herbivory and Parasitism
Predatory Adaptation
Cryptic Coloration
Mullerian Mimicry
Batesian Mimicry

Hank wraps up Crash Course Ecology by taking a look at the growing fields of conservation biology and restoration ecology, which use all the moves we've learned about in the past eleven weeks, and applies them to protecting ecosystems and to cleaning up the messes that we've already made.

Chapters:
1) Types of Diversity
2) Conservation Biology
A) Small Population Conservation
B) Declining Population Conservation
3) Restoration Ecology
A) Structural Restoration
B) Bioremediation
C) Biological Augmentation

In the world of ecology, the only constant is change - but change can be good. Today Hank explains ecological succession and how ecological communities change over time to become beautiful, biodiverse mosaics.

Chapters:
1. Primary Succession :1
2. Secondary Succession
3. Climax Community Model
4. Intermediate Disturbance Hypothesis :1

Hank brings us to the next level of ecological study with ecosystem ecology, which looks at how energy, nutrients, and materials are getting shuffled around within an ecosystem (a collection of living and nonliving things interacting in a specific place), and which basically comes down to who is eating who.

Chapters:
1) Defining Ecosystems :1
2) Trophic Structure :1
a) Primary Producers
b) Primary Consumers
c) Secondary Consumers :1
d) Tertiary Consumers :2
e) Detrivores :1
3) Bioaccumulation

With a solid understanding of biology on the small scale under our belts, it's time for the long view - for the next twelve weeks, we'll be learning how the living things that we've studied interact with and influence each other and their environments. Life is powerful, and in order to understand how living systems work, you first have to understand how they originated, developed, and diversified over the past 4.5 billion years of Earth's history. Hang on to your hats as Hank tells us the epic drama that is the history of life on Earth.

Chapters:
1) Archaean & Proterozoic Eons
a) Protobionts
b) Prokaryotes
c) Eukaryotes

If being alive on Earth were a contest, humans would win it hands down. We're like the Michael Phelps of being alive but with 250,000 times more gold medals. Today, Hank is here to tell us the specifics of why and how human population growth has happened over the past hundred and fifty years or so, and how those specifics relate to ecology.

Chapters:
1) R vs. K Selection Theory
2) Causes of Exponential Human Growth
3) Human Carrying Capacity
4) Ecological Footprints
5) Causes for Decline in Human Growth Rate

Hank introduces us to biogeochemical cycles by describing his two favorites: carbon and water. The hydrologic cycle describes how water moves on, above, and below the surface of the Earth, driven by energy supplied by the sun and wind. The carbon cycle does the same... for carbon!

Chapters:
1) Hydrologic Cycle
A) Clouds
B) Runoff
C) Oceans
D) Evapotranspiration

2) Carbon Cycle -
A) Plants -
B) Fossil Fuels -
C) Oceans -
D) Global Warming -

Hank describes the desperate need many organisms have for nutrients (specifically nitrogen and phosphorus) and how they go about getting them via the nitrogen and phosphorus cycles.

Chapters:
Nitrogen Cycle
Nitrogen Fixing Bacteria
Nitrifying Bacteria
Denitrifying Bacteria
Phosphorous Cycle
Lithosphere
Plants
Animals
Decomposers
Aquatic & Marine Ecosystems
Sedimentation & Weathering
Synthetic Fertilizers
Review

Hank talks about the last major way humans are impacting the environment in this penultimate episode of Crash Course Ecology. Pollution takes many forms - from the simplest piece of litter to the more complex endocrine disruptors - and ultimately, humans are responsible for it all.

Chapters:
1) Natural Compounds :1
a) Carbon
b) Nitrogen and Phosphorous :2
c) Cyanide
d) Mercury
e) Sulfur & Nitrogen Dioxide

Population ecology is the study of groups within a species that interact mostly with each other, and it examines how they live together in one geographic area to understand why these populations are different in one time and place than they are in another. How is that in any way useful to anyone ever? Hank uses the example of the West Nile virus outbreak in Texas to show you in this episode of Crash Course: Ecology.

Chapters:
1) Density & Dispersion
2) Population Growth
3) Limiting Factors
a) Density Dependent
b) Density Independent
4) Exponential & Logistical Growth
5) How to Calculate Growth Rate