Biodiversity Issues Unit5:生物多样性问题 Human Influence wilderness WIlderness Addition of foreign species 00950= Managed forests rangelands, and lakes Agriculture and Extinction aquaculture Degree of human influence
Biodiversity Issues Biodiversity Issues Unit 5: Unit 5: 生物多样性问题 生物多样性问题
Biodiversity Loss and Extinction Two basic terms Biodiversity: a broad term used to describe the diversity of genes, species, and ecosystems in a region Extinction: the death of a species, the elimination of all the individuals of a particular kind Biodiversity is lost when a species becomes extinct Extinction is a major consequence of human domination of the earth Complete extinction: all the individuals of a species are eliminated Local extinction: the future of the species is not encouraging
Biodiversity Loss and Extinction • Two basic terms – Biodiversity Biodiversity: a broad term used to describe the diversity of genes, species, and ecosystems in a region. – Extinction Extinction: the death of a species, the elimination of all the individuals of a particular kind. • Biodiversity is lost when a species becomes extinct. • Extinction is a major consequence of human domination of the Earth. – Complete extinction Complete extinction: all the individuals of a species are eliminated. – Local extinction Local extinction: the future of the species is not encouraging
Causes of extinction Probability of becoming extinct Most Likely to become Extinct Least Likely to Become Extinct Low population density High population density Found in small area Found over large area Specialized niche Generalized niche Low reproductive rates High reproductive rates
Causes of Extinction • Probability of becoming extinct
Extinction as a result of human Activity At one time, a human was just another consumer somewhere in the food chain -just like other animals Human fell prey to predators Human died as a result of disease and accident As human population grew, and as their tools became more advanced, the impact that a single man could have on his surroundings increased tremendously Purposeful use of fire -to change ecosystems Wood was harvested for fuel and building materials Human displaced other kinds of organisms
Extinction as a Result of Human Activity • At one time, a human was just another consumer somewhere in the food chain – just like other animals. – Human fell prey to predators. – Human died as a result of disease and accident. • As human population grew, and as their tools became more advanced, the impact that a single man could have on his surroundings increased tremendously. – Purposeful use of fire – to change ecosystems. – Wood was harvested for fuel and building materials. – Human displaced other kinds of organisms
Changes in the ability of humans to modify their world
Changes in the ability of humans to modify their world