1.
Nature's Relationships
(02:34)
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The relationship between a predator and its prey is just one type of relationship between living things. The natural world is made up of a vast network of complex relationships.
2.
Evolution of Predator-Prey Relationships
(02:29)
Colonies of blue-green algae called stromatolytes produced the first oxygen in Earth's history and transformed its atmosphere. Stromatolytes made it possible for life to evolve and for relationships between living things to develop.
3.
Hunting Strategies of Predators
(02:41)
Predators evolve in ways that enable them to hunt effectively. A mantis has evolved to look like the orchids on which it hunts crickets, a snapping turtle's worm-like tongue attracts fish, and a small spider kills larger prey with strong venom.
4.
Defense Strategies of Prey: The Passion Flower Vine
(03:38)
Like any prey, passion flower vines evolve to protect themselves from predators. The vines produce structures that mimic butterfly eggs in order to deter butterflies from laying real eggs that will become leaf-eating caterpillars.
5.
Competition Influences Evolution
(04:04)
Vultures and other scavengers compete aggressively for carrion. The development of different body shapes and sizes allows several species of African hoofstock to share leaves from the same acacia trees.
6.
Competition Promotes Cooperation
(05:49)
Survival for ring-tailed lemurs and for meerkats depends on living in groups to protect territory and each other. Termites have developed adaptations that enable individuals to perform specific functions that benefit the entire colony.
7.
Cooperation Between Species
(02:00)
Animals of different species have found mutually beneficial ways to cooperate. Some marine organisms clean the parasites and dead skin off of fish.
8.
Partnerships Between Insects, Plants, and Fungi
(04:31)
The relationship between insects and plants enables insects to feed and plants to be pollinated. Ninety percent of all plants, including giant California redwoods, rely on networks of fungi in the soil to bring water and nutrients to their roots.
9.
Evolution of Mitochondria
(01:59)
The mitochondria found in an animal's cells convert food to usable energy. The relationship between mitochondria and cells has evolved over billions of years.
10.
Parasites and Viruses
(03:38)
Oxpeckers eat insects and ticks that plague most grazing African animals, but the birds also feed on the blood of their hosts. More rabbits are killed by a viral disease spread by parasites than are killed by predators.
11.
Evolution and Sexual Reproduction
(03:13)
During sexual reproduction genetic material is shuffled to create variety within a species. Sexual reproduction is evolution's way of ensuring the success of future generations.
12.
Mating Rituals and Evolution of Elk
(03:00)
Male elk compete during mating season to impress females. Female elk drive the evolution of their species by selecting the males with whom they mate.
13.
Appearance Matters to Birds
(04:11)
The females of some bird species select mates based on their color. Brightly colored males are often healthier and more likely to pass on strong genetic material than males who are dull.
14.
Evolution and Diversity of Life
(03:58)
The differing mate selection preferences of same species female fish has led to the evolution of new fish species. Relationships among organisms are a driving force of evolution and have helped create the variety of life that exists on Earth today.