Species Diversity; 2 variables – the richness( the amount of species in an ecosystem) and evenness (in one dessert 1 lagartija and 5 cactus and in the other dessert 5 lagartijas and 1 cactus)

Genetic diversity; Range of genetic materials in an ecosystem of species. humans can alter the genetic diversity by artificially breeding or genetically engineering populations.

Habitat diversity; different habitats in a same ecosystem.

If there is more diversity in one ecosystem will be more healthy but there are special exception.

High biodiversity advantages:

  • If there are big amount of biodiversity of plants, if there is a floods, insect attac or other things there will be little change in the ecosystem.
  • Genetic diversity so resistance to diseases.
  • some plants have long roots so they will bring the nutrients to the surface.

High biodiversity disadvantages_

  • Pioneer species could invade areas quilcky this can cause fragmentation or degradation.
  • Some species will be advantage of the grazing but other will be disadvantage because of the big aunt of grass (like the cows and the aunt)
  • Some ecosystem can be healthy with little diversity.

Hotspots; regions with high level of biodiversity under threat because of human diversity.


  • Each individual is different due to their genes and mutation
  • Each specie will be different adapted to the environment
  • Resource will be limited so there will be competition.
  • over time these changes show and the population gradually changes.

Natural selection; Some species will be more adapted to one environment so the other species will not adapt and will die.

Speciation: From one same specie there will may be different species because of natural causes. For example the cat and the cheetah.

different options of speciation;

– Physical barriers; mountains that will separate different species. when the continents splits some species stay in one side and some in the other side so they have to adapt to the climate change for example. (adaptation)

– Land bridges; there is new land so that the animals could invade new areas

– Continental drift; adaptation to different climate change, in te same specie some will have to adapt to different climate, food supply.

Plate activity influences in biodiversity

Where the plate meet, they may;

  • slide past each other (nothign happens)
  • Diverge, which cause physical separation of population.
  • Converge, physical separations (mountains, Land bridges)

Similar group of animals; it prove that all continents where joined millions of years ago because of the similarities of different species.

Background and mass extinctions; before ( every 1 million species per year, one specie was extinct) from then to now there have been 5 mass extinctions and it is said that we are in the 6th one that is the bigger due to te fact of the human activity.

“Living dead” species, there are so little that they don’t have chances to survive.

Human are direct cause of ecosystem stress because:

  • Transform the environment ( cities, agriculture)
  • Overexploit other species – (fishing, hunting)
  • Introduce alien species – (human introduce a specie that does not belong to that habitat)
  • Pollute the environment – (pollution fro the environment)


100 species every 1 million every ear

Factors that help to maintain biodiversity

Complexity of ecosystem; The more complex food web is the more adapted it is to the loss of the prey.

Stage of succession: young ecosystem that are going successions are more vulnerable that the old ecosystem because they get use to it.

Limiting factors: If there is a limiting factor affect a specie will not affect a big ecosystem.

Inertia: the capacity that an ecosystem resist change or recover quickly.

Factors that lead to the loss of biodiversity.

Natural hazards: natural events that have negative impact on environment for example earthquakes, volcanic eruptions.

Loss of habitat: Human impact and destroy of ecosystem for example build structures.

Fragmentation of habitat: Constructions in a big piece of land that separate lands so the species fragment.


Overexploitation: too much hunting of too much fish, overexploitation of a specie.

Introducing the non-active species: When human put a specie that is not suitable for that environment

Spread of disease: If the disease mutated could affect many species and could never go away from the habitat

Modern agricultural practices: reduces the diversity because of the monocultures.


  • Narrow geographical range:
  • Small population size, low genetic diversity
  • Low population densities and large territories: the species separate between fragmentation and it is imposible to interbreed so is in their way to extinct.
  • Few population of the species: low population of species or only in one country there is a special specie
  • A large body: for example the bear that is big and compete with the human
  • Low reproductive potential: long time to reproduce ( time of recover or pregnancy)
  • Seasonal migrants: when one animal migrates and the land that is crossing is dangerous some of them will not survive the migration.
  • Poor dispersers: species that can not easily move.
  • Specialized feeders or niche requirements: the food that one species eat may be destroyed do that animal will have nothing to eat ( koala bear and eucalyptus)


Why conserve biodiversity

Direct values

Food sources

– we eat other species whether animal or plant

– Need to preserve old varieties in case we need them in the future

Natural products

– Medicines

– oil plants give us oil

– Honey

Indirect values

Environmental services:

– Fertilization

– Soil and water resources

– Plants give us oxygen

Scientific and educational value: study plants and animals because we need to know.

Biological control agents: Species control the over population of other species

Future potential for even more uses: future uses for ecosystem

Human health: first antibiotic are extreid from fungi

Recreational: provide employment in vacational areas like resorts in desertic beaches

Conservation and preservation pf biodiversity

  • Conservation biology: sustainable use and management of the natural resources
  • Preservation biology: exclude humans from areas that are not developed so that they can not explode it.
  • Sustainable development: take care of resource so that not negatively impact for the future generations.