Paul Andersen describes pieces of evidence that Charles Darwin used to support the idea of evolution and his process of natural selection. He begins with the following evidence use in the Origin of Species; artificial selection,...

The human eye is an amazing mechanism, able to detect anywhere from a few photons to a few quadrillion, or switch focus from the screen in front of you to the distant horizon in a third of a second. How did these complex structures...

Scientists often use the phrase “anatomically modern humans” to describe the point when our ancient ancestors looked like us. But when did humans become behaviorally modern?

Paul Andersen describes our place on the Earth in the Solar System within the Milky Way Galaxy in the Universe. The make-up and origins of the Universe are included along with stellar evolution. A teaching progression K-12 is also included.

Among living things, the color blue is oddly rare. Blue rocks, blue sky, blue water, sure. But blue animals? They are few and far between. In this video, we'll look at some very cool butterflies with Bob Robbins, Ph.D. from Smithsonian's...

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

n 10 episodes John Green, Hank Green, and Emily Graslie teach you about, well, everything. It’s Big History! This course will take you on a whirlwind journey from the creation to the death of the universe and is based on the Big History...

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...

In this video Paul Andersen explains how scientific theories are created and modified over time. He starts by discussing the theory of natural selection as a model for the creation and modification of theories. He gives examples of...

In which John Green, Hank Green, and Emily Graslie teach you about, well, everything. Big History is the history of everything. We're going to start with the Big Bang, take you right through all of history (recorded and otherwise), and...

Hank and his brother John discuss heredity via the gross example of relative ear wax moistness.

Paul Andersen reviews the major components of the homeostasis. He explains how organisms respond to abiotic and biotic factors in their environment with feedback loops. He shows how responses can be behavioral or physiological.

Hank introduces us to the "simplest" of the animals, complexity-wise: beginning with sponges (whose very inclusion in the list as "animals" has been called into question because they are so simple) and finishing with the most complex...

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,...

Tropical rainforests are known for being super biologically diverse _ they're full of different species, from colorful birds and insects to plants and fungi. We haven't even come close to cataloguing everything that's there.

Paul Andersen explains how eukaryotic cells were formed through a process of endosymbiosis. He describes how aerobic bacteria became mitochondria and cyanobacteria became chloroplasts. He mentions an example of symbiosis that occurs...

Waddling along the parched Australian earth, a female platypus is searching for fresh water. Over the past year, a severe drought turned rivers and streams to mere trickles. She barely survived and was unable to reproduce. Could the next...

In 2013, a treasure trove of unusual fossils were uncovered in a cave in South Africa, and researchers soon realized: these were the remains of a new species of ancient humans. Paleoanthropologist Juliet Brophy takes us inside the...

Hank veers away from human anatomy to teach us about the (mostly) single-celled organisms that make up two of the three taxonomic domains of life, and one of the four kingdoms: Archaea, Bacteria, and Protists. They are by far the most...

Hank guides us through the process of natural selection, the key mechanism of evolution.

Paul Andersen details examples of natural selection in the world. He starts by explaining how changes in global temperatures are causing plants to adapt. He explains how mutations cause changes in phenotype which give organisms varying...

Paul Andersen explains how natural selection is a major mechanism in evolution. The video begins with a discussion of Charles Darwin and the details of natural selection. The data of the peppered moth during the industrial revolution is...

Paul Andersen shows how homeostasis reflects of evolution through time. The endocrine system shows continuity through flatworms, earthworms and vertebrates. However the respiratory system shows change as organisms move onto land. The...

Hank introduces us to one of the most diverse and important families in the tree of life - the vascular plants. These plants have found tremendous success and the their secret is also their defining trait: conductive tissues that can...