Biogeography Flashcards
what is biogeography
the study of the distribution of species and ecosystems in geographic space and through geological time
what are biogeographic realms, or ecozones
large scale groupings of biomes with related evolutionary histories
what is biogeography a combination of? two disciplines
ecology and history
definition of a population
group of interbreeding individuals
definition of a species
all populations that can interbreed
definition of a community
collection of different species living in proximity
what two categories of factors cause population change
instrinsic and extrinsic factors
what is a habitat
physical environment of a species or population that has the conditions to sustain a population
how are species distributed
along environmental gradients
population increases where environment becomes more favourable
where there are common preferences, a community is created
what halts populations growth
environmental factors
what is the biotic potential
the growth of a population in optimal environmental conditions without resource limitations
what is the carrying capacity
when the birth rate = death rate (any more and resources become limiting)
what are boom and bust cycles
most populations go through a lot of change over time. boom: rapid growth, bust: rapid die back due to depletion of resources or overpredation
by how much does the human pop. grow each year
80 million
what is the carrying capacity of spaceship earth
8 billion most likely
by how much are we currently exceeding planetary boundaries
60%
what is coevolution
when two species evolve together due to their interdependence
what is mutualism
ecological interaction between two species where each has net benefit
what is symbiotic relationship
close physical contact in mutualism
give two examples of an exploitative relationship
predation and parasitism
what is commensalism
one species benefits without affecting the other
what is the purpose of inter or intra specific competition
evolutionary driver
what is a fundamental niche
all the environmental conditions where a species is able to live, no competition for resources
what is a realised niche
where a species actually lives, competition for resources
what is competitive exclusion
species with the same niche compete until one is displaced- prompts niche differentiation
what are the two main strategies for species to survive
generalists: more in the far north which has larger niches
specialists: more at the equator, small climatic range and small niches
name three ways that biodiversity is measured
- genetic diversity- variability among DNA of individuals in a pop. or species
bigger genetic diversity= faster adaptation - habitat diversity- diversity depends on and promotes ecosystem stability
- species diversity- richness, evenness, dominance
threats to ecosystems
loss of habitat
habitat fragmentation
loss of species
removal of keystone species through hunting etc.
what is species vulnerability
when a species has overly selective breeding habits and feeding
larger species more vulnerable as they need more territory and food
what are the two types of conservation based on location
in-situ or out-situ
give reasons that biodiversity is important (utilitarian)
financial potential cures tourism aesthetics spiritual and health benefits ecological benefits
what do intrinsic reasons for biodiversity argue for
not human centred
moral obligation to protect other species
eg. deep ecology
who made a zoogeographic map and published alongside Darwin?
Alfred Russel Wallace
what did the zoogeographic map show
based on evolutionary relationships
20 regions within 11 larger realms
most similarity of species in northern hemisphere
least similarity in south and isolated areas
what is endemism
a species being native to a single geographic location
why is there a high percentage of marsupial mammals in australia
endemism has produced marsupial versions of placental mammals, the isolation of the continent allowed native species to develop
3 responses to environmental change
move- depends on connectivity, competition and available space
adapt - depends on behavioural plasticity of species and time
die
what are k-selected species
limited by carrying capacity, larger and longer-lived, relatively stable
what are r-selected species
limited by reproductive rate, smaller and shorter-lives, relatively unstable
how did changes in climate and environment alter species distribution in the Quaternary period
cyclic environmental change through the repeated expansion and contraction of range as ice melted and built up
what is anageneis
evolution of a species that continues to exist as an interbreeding population
what is cladogeneis
evolution of a species that splits into two lineages that do not interbreed-> creates separate species
give two situations where a new species may arise
physical isolation or reproductive isolation
when was the last peak extinction
65 million years ago, when the dinosaurs died out
when should the current mass extinction actually be happening
in 800-10000 years
what does evolutionary geography study
which factors promote speciation and which cause extinction?
