Species (allopatric speciation), Extinction and Phylogenetic trees Flashcards
define biodiversity
biodiversity is the variety of organisms in a given area (or in the world).
what are the three types of biodiversity
SPECIES DIVERSITY: is the variety of different species living in a particular area.
GENETIC DIVERSITY: refers to the variety of genes present in a particular population
ECOSYSTEM DIVERSITY: refers to the variety of physical environments in which organisms can live in
what are the different threats to biodiversity
Invasive species
eg) The brown rat consumes vast quantities of human food, damages property and causes electrical hazards by chewing through wires.
Climate change
eg) The sex of the leatherback turtle is determined by the temperature of the egg in the nest during incubation.
define species
A species is a group of organisms that can reproduce with one another in nature and produce fertile offspring
how do new species form
through Allopatric speciation
what is allopatric speciation
Allopatric speciation is the development of new species when members of the population become geographically separated
name some examples of geographical isolation and what are their importance
Geographic isolation isn’t a quick process. Examples include:
the development of mountain ranges
the movement of islands
the formation of canyons
The importance of the geographical barrier is to stop the two populations from being able to reproduce with each other.
what is natural selection
when there are different factors in different environments and therefore the different species group start to adapt and develop new phenotypes
what is the importance of natural selection
Those best suited to their environment can obtain more food, resources and breeding space so therefore breed more.
define extinction
Organisms that no longer live on planet Earth
what has caused mass extinctions is the past and what are factors causing extinction today
Obvs the meteorite
But factors now that are influencing it include:
excessive clearing of native grasslands
unsustainable loss of old growth forests
overgrazing
changed frequency of fire
degradation of water quality in rivers, lakes and estuaries
introduction of exotic plants, predators and diseases
unregulated exploitation of terrestrial and marine wildlife
population growth of humans and increased urbanization
increased levels of pollution
define phylogeny
the history of the evolution of a species or group
explain what a phylogenetic tree shows
A phylogenetic tree is a diagram that represents evolutionary relationships among organisms.
The pattern of branching in a phylogenetic tree reflects how species or other groups evolved from a series of common ancestors
