Compendium Review Topic two Unit four

• Deep Time Evolutionary History Evolution is the change in the inherited traits of a population from generation to generation. These traits are the expression of genes that are copied and passed on to offspring during reproduction. Mutations in these genes can produce new or altered traits, resulting in heritable differences between organisms. New traits can also come from transfer of genes between populations, as in migration, or between species, in horizontal gene transfer. Evolution occurs when these heritable differences become more common or rare in a population, either nonrandomly through natural selection or randomly through genetic drift.

Prebiotic: the developments taking place before the origin of the life, the emergence of physico-chemical complexity: the Big Bang, space and time, energy and particles, atoms and the different elements, molecules up to organic polymers, simple dissipative structures.
Biological: the origin of life and the further development of the specifically biological aspects of it: DNA, reproduction, autopoiesis, prokaryotes vs. eukaryotes, multicellularity, sexual reproduction, the species.
Cognitive: the origin of mind, the basic cybernetic, cognitive organization, going from simple reflexes to complex nervous systems, learning, and thought.
Social: the development of social systems and culture: communication, cooperation, moral systems, memes

Human Ecology

Human ecology is an academic discipline that deals with the relationship between humans and their natural, social and created environments. Human ecology investigates how humans and human societies interact with nature and with their environment.

Trophic levels are the feeding position in a food chain such as primary producers, herbivore, primary carnivore, etc. Green plants form the first trophic level, the producers. Herbivores form the second trophic level, while carnivores form the third and even the fourth trophic levels. In this section we will discuss what is meant by food chains, food webs and ecological pyramids.

Phosphorus enters the environment from rocks or deposits laid down on the earth many years ago. The phosphate rock is commercially available form is called apatite. Other deposits may be from fossilized bone or bird droppings called guano. Weathering and erosion of rocks gradually releases phosphorus as phosphate ions which are soluble in water. Land plants need phosphate as a fertilizer or nutrient.

• Human Population and Biodiversity

The human population growth of the last century has been truly phenomenal. It required only 40 years after 1950 for the population to double from 2.5 billion to 5 billion. This doubling time is less than the average human lifetime. The world population passed 6 billion just before the end of the 20th century. Present estimates are for the population to reach 8-12 billion before the end of the 21st century. During each lecture hour, more than 10,000 new people enter the world, a rate of ~3 per second!
Of the 6 billion people, about half live in poverty and at least one fifth are severely undernourished. The rest live out their lives in comparative comfort and health.

Biodiversity is the variation of taxonomic life forms within a given ecosystem, biome or for the entire Earth. Biodiversity is often a measure of the health of biological systems.There are five main causes for biodiversity loss and extinction on Earth. These are: habitat loss, introduction of alien species, pollution, overexploitation of plant and animals, and disease. Diodiversity is a good thing to keep because it provides us with medicinal value, agricultural value, and comsummptive use values. They also give waste disposal, freshwater procision through the water biogeochemical cycle, prevention of soil erosion, function of biogeochemical cycles, climate regulation, and ecotourism.