Chapter 1: Biology in the 21st Century

Biology is the Study of All Forms of Life

from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. Charles DarwinDr James Rosindell, Imperial College London, http://www3.imperial.ac.uk/

Two Main Groups of Life: Eukaryotes Prokaryotes

Prokaryotes: single-celled mostly bacteria

Eukaryotes: animals plants fungi protistsEarth Has Amazing BiodiversityAll Life and the Places Where It Lives are called the Biosphere The biosphere includes many environments.The biosphere interacts with all other spheres: atmosphere, hydrosphere, lithosphere

Biodiversity is the collection of all life on Earth

Biodiversity increases from the equator to the polesTropical rainforests have many species of plants and animalsTemperate forests have less species than tropicsPolar areas have only a few species

Heat map of the latitudinal biodiversity gradient terrestrial vertebrate species. Red colors indicate high biodiversity. Blue colors indicate low biodiversity.

Source: Mannion et al. (2014), based on work by Clinton Jenkins.http://www.palaeontologyonline.com/articles/2014/patterns-in-palaeontology-the-latitudinal-biodiversity-gradient/What is a Species?A species is a single, particular kind of organism that can reproduce fertile copies of its same kind. It is estimated there are 8.7 million species on Earth. So far, only about 1.3 million have been identified and named. http://www.mnn.com/earth-matters/animals/photos/9-newly-discovered-species/look-what-we-found

Psychedelic frogfish (Indonesia, 1999)Caqueta titi monkey (Southern Columbia, 2010)Yeti crab (2006)Blossom Bat (New Guinea)What are Organisms?Organisms are individuals of a species. They are any single living thing. Examples of organisms: person, shrimp, bacterium, squirrel, bee, plant

All organisms have one or more cellsMany bacteria are single-celledAll animals, plants, and fungi have many cells

All organisms share four common characteristics (according to our textbook)They are made of one or more cells.They all require energy for metabolism.They all respond to or interact with their environment.They all contain DNA that they pass on to their offspring.

All organisms are made of cellsSome organisms (like bacteria) are made of only one cell: unicellularMany more types of organisms are made up of many cells: multicellularIn multicellular organisms, cells have different functions, e.g. muscle cells, skin cells, lung cells, etc. Cells are organized into tissues and organs with different structures for different functions

All cells need energyAll living things use chemical energyPlants collect energy from the sun and use it to make their own chemical energy (sugars)Animals get energy from eating plants or other animals and breaking them down to derive chemical energyEnergy is required for metabolism: the chemical processes that make or break down materials. All organisms respond to their environmentRespond to stimuli such as light, temperature, touchOrganisms may do different things in response to changes in their environmentNon-living things (e.g. rocks, chopped wood) dont respond to their environmentAll organisms reproduce and go through stages of developmentUnicellular organisms reproduce when one cell divides into twoMulticellular organisms by either asexual reproduction (one individual forms another) sexual reproduction (two individuals combine genetic information to produce offspring)All reproduction involves passing on an organisms DNA to its offspringAll organisms share four common characteristicsThey are made of one or more cells.They all require energy for metabolism.They all respond to or interact with their environment.They all contain DNA that they pass on to their offspring.