Biodiversity and Population Ecology Flashcards
Panspermia Hypothesis
Microbes and chemicals crashed on earth from asteroids/meteors
Chemautotrophic Hypothesis
Chemicals combined in deep-sea hypothermal vents
Intelligent Design Hypothesis
Life was created by intelligent superior beings
Biological Evolution
The genetic change in populations of organisms across generations; results from random genetic change, and is driven by natural selection
Ultimately _ are what drive genetic change
Mutations
Once a mutation has been successfully passed on, we call it an _, or simply _
Adaptive trait; adaptation
Natural Selection
The process by which traits become more desirable by enhancing changes for survival in genetic populations; over time genotype and phenotype of an organism are changed
Biodiversity
Sum total of all organisms in a given area
Species
One particular organism
Population
A group of species living in the same area
Allopatric Speciation
The formation of two new species by physical separation of two members of the original species
Species Diversity
Number of varieties of species in the world or in a given region
There are arguments on what constitutes a distinct species. Is it…
A group that shares characteristics due to shared common ancestry
OR
The ability to interbreed
Genetic Diversity
Within species there can be a great deal of genetic variation; phenotypic variation
The vast majority of species worldwide are _
Insects
Latitudinal Gradient
Biodiversity increases along latitudes; majority of species are found along equator; possible explanations for this suggest that generalist species live in temperate and polar latitudes and specialist species live in tropical latitudes
Generalist
Can adapt to many surroundings and food types (K species: few babies)
Specialist
Adapt to one/few types of surroundings and food types (R species: lots of babies)
Extinction
The ending of a species on earth
Extirpation
The disappearance of a species from a given area, but not from the earth globally
5 prior mass extinction events (where 1/2 of the species are lost):
Ordovician extinction: 440 mya, unknown cause
Devonian extinction: 370 mya, unknown cause
Permo-Triassic extinction: 250 mya, unknown cause
Triassic extinction: 202 mya, unknown cause
Cretaceous-Tertiary extinction: 65 mya, asteroid impact?
Habitat Alteration
Human activities that result in the changing/alteration of an area’s habitat; often drives species away from their natural homes; urbanization/suburban crawl; some animals actually benefit; by far the greatest problem of biodiversity, accounting for around 85% of population declines
Invasive Species
Non-native species that are introduced into an environment and absolutely take over, displacing natural residents or consuming them; mostly accidental, but has had a history of purposeful introduction; don’t have a natural predator
Climate Change
The warming of the earth’s temperatures; an indirect human impact; even small temperature changes worldwide can cause some species to lose their habitat; polar regions and mountainous regions
