Biodiversity
is the variety of all life on earth. It includes genetic diversity, species diversity and habitat diversity.
Factors that affect biodiversity
climate, Age of the area (Older areas tend to have higher biodiversity.), environmental stability, and range of habitats.
Species diversity
is the number of different species in a given area taking into account the RICHNESS and EVENESS of the species. It is important because it results in a balanced ecosystem; species interact with each other and the abiotic environment and perform various functions within the system.
Richness
is a measure of the number of different species in an area; more species means a richer environment.
Evenness
looks at the relative abundance of the species.
Measuring species diversity
Simpson Diversity Index Formula
Genetic diversity
is the variation of genes within the genetic pool of a population of a species.
Importance of genetic diversity
species can be more resilient to disturbance, extinction is prevented, cannot be regained, and if not present can cause inbreeding.
Habitat diversity
is the range of different habitats in an area.
Evolution
is the change in the genetic composition and therefore the heritable traits of a population over successive generations and it can impact individuals and whole species.
Causes of evolution
mutations (a change in DNA), and natural selection (The gene variation has survival advantages)
Evidence for evolution
artificial selection, convergent evolution, embryology, Vestigial structures, Biogeographical distribution and fossils.
Speciation
is the formation of a new species through biological processes.
What pushes speciation
Geographic Isolation - Populations are physically separated and can no longer interbreed. Temporal Isolation - Populations live their lives at different times of the day and so do not meet to breed. Behavioral Isolation - They have different mating rituals.
How the concepts of evolution, speciation and biodiversity are linked
Evolution drives speciation, and in various ways, speciation creates more species, therefore, increasing biodiversity.
Natural Selection
the gradual evolutionary change that results from genetic variation in each generation to adapt.
Variation
Individuals of a species show a wide range of genetic diversity or variation. This variation may be in the physical or behavioural attributes, such as size, fur colour, eye colour and mating calls
Survival of the fittest
useful concept as it encompasses the most important aspects of natural selection: survival and reproductive success (secure a mate to reproduce and pass your genes on to the next generation)
Plate tectonics
a scientific theory is based on the concept of continental drift. The theory explains the motion of the earth's lithosphere (outer layer) and the impact that it has had on the distribution of the continents.
Impacts of the movement of the tectonic plates on evolution and biodiversity
The separation and movement of the continents creates new islands and moves the continents into different climatic zones forcing evolutionary change. The movement creates four types of plate boundaries each associated with different types of activity with varying impacts on biodiversity. Hotspots and other volcanic activity create new land.
Endemic Species
a species unique to a particular location and not found elsewhere
How does climatic variation impact evolution through natural selection thus biodiversity
The different climates around the globe impact evolution through natural selection, as this range in climates provide diverse habitats, niches and food sources all of which support the process of natural selection
Divergent Plate margins
divergent margins are where plates move apart and this creates opportunities for diversification
Convergent plate margins
As plates move together, they create mountains, volcanoes, land bridges and massive ocean trenches.
Volcanic activity and its support on biodiversity
Volcanic activity creates new habitats and niches both on land and in the oceans. Any new land created by volcanic eruptions is subject to succession as species colonise the area. If volcanic eruptions are in the oceans they create new islands and seamounts.
Mass extinction
a sudden global decrease in the number of species over a relatively short period of time.
Background extinction
the standard rate at which species go extinct.
Causes of past mass extinctions
glaciation, bolide impacts (meteors that burn up in the sky), large-scale volcanism, sudden release of large amounts of methane from the sea floor, climate change, sea level fluctuations, asteroid impacts, human activity
Problems associates with directly counting the number of species globally
species may be counted more than once, small groups are difficult to identify, some species such as deep sea organisms are difficult to access, some species may become extinct even before we know about them...
Humans influence on biodiversity
Growth in the human population increases demand on natural resources which has led to over-exploitation of species, habitat degradation, and introduction of alien species as well as pollution.
Habitat fragmentation
when large blocks of habitat are cut into smaller pieces by development such as roads or housing.
Habitat Degradation
when their condition declines due to factors such as pollution, invasive species, and over-utilization of natural resources
Invasive species
an organism that is not indigenous, or native, to a particular area
The International Union for Conservation of Nature (IUCN) Red List
provides information and analysis on the status, trends and threats to species in order to inform and catalyze action for biodiversity conservation
Distinguish between 'extent of occurrence' and 'area of occupancy'
The extent of occurrence is the boundary that can be drawn around the sites the species occupies. Hence the extent of occurrence includes the area of occupancy and may also contain habitats within the boundary not used by the species.
Factors that contribute to species vulnerability
degree of specialization, their trophic level (organisms high up in a food chain may be exposed to higher levels of pollutants due to the process of bio-magnification and bio-accumulation.)
Extinct Species
Dodo, Tasmanian Tiger, mammoths
Critically endangered species
Hawksbill turtle, Sumatran Orangutan
Conservation International Criteria for a biological hotspot
It must have at least 1,500 vascular plants as endemics, It must have 30% or less of its original natural vegetation.
The emergent layer
which is the highest layer and consists of trees that extend beyond the general canopy.
The canopy level
that is dense and significantly reduces light penetrating further into the forest.
The understory layer
below the canopy layer consisting of shrub plants and tree saplings.
The forest floor or ground layer
receives less than 2% of the light, so green plants are limited in number. Humidity is very high due to the limited air movement and high evaporation rates in the layer.
Examples of IGOs
The United Nations Environment Programme (UNEP), Food and Agricultural Organizations (FAO), Intergovernmental Panel on Climate Change (IPCC).
Umbrella species
these are often large species requiring large habitat areas. Protecting the habitat of this species also protects the habits of other species.The Giant panda is both a flagship species and an umbrella species.
Keystone species
these species interact through the food web with other species in the community and if lost could lead to the demise of other species. Conserving a keystone species helps to protect the integrity of the community.
In-situ conservation
protection of species in their habitat.
Ex-situ conservation
improve the probability of survival of the species by taking them out of their habitat and breeding them in captivity; with the intention of re-introducing them back into the wild in the future.
Utilitarian value
is where there is an economic value associated with the use of resources
Non-utilitarian value
is when use does not have any economic value.