Species Horse Donkey Mule Members of a species

Species Horse Donkey Mule

Members of a species may be reproductively isolated in separate populations. New species arise when one existing species splits into two reproductively isolated populations that go their separate ways. This most commonly happens when the two populations become physically separated from each other (allopatric speciation) e. g. The genome map suggests that about 2 million years ago, individuals of a single ape species were divided by the Congo River. The populations must be reproductively isolated, so that they could not interbreed and there was no gene flow between the groups. As the environmental conditions were different on either side of the river they started evolving separately.

Chimpanzee Bonobo The allele frequencies in the two populations became different. They became separate species — chimpanzees and bonobos — about 1 million years ago. Bonobos have a genome which is 99. 6 percent identical to the chimpanzee genome and 98. 7 percent identical to the human genome — basically they are just as related to humans as chimpanzees.

Photoautotrophic organisms use light as an energy source which enables them to synthesise their own organic molecules (photosynthesis). Chemoautotrophs use the energy from reduced compounds, which they oxidise, to enable then to synthesise organic materials e. g. NH 4+ -> No 3 - + 3 H H 2 + CO 2 -> CH 2 O + O 2 (not balanced)

Ecosystems have the potential to be sustainable over long periods of time Many different factors interact to determine population size, and it can be very difficult to determine which factors are the most important. These factors can be split into two broad groups: Abiotic Factors: Non-living components of the environment; e. g. Temperature, Humidity, p. H, altitude. These factors tend to control a population in a density independent manner. Biotic Factors: Living components of the environment, as all living things compete, these factors tend to be density dependent. e. g. competition for mates, territories, are forms of competition within a species i. e. intra specific competition. An organism’s niche refers to the biotic and abiotic factors that the organism needs in its habitat.

Mixotroph

Detritivore: an organism that ingests non-living organic matter. Saprotroph: an organism that lives on or in nonliving organic matter, secreting digestive enzymes into it and absorbing the products of digestion. Consumer: an organism that ingests other organic matter that is living or recently killed.