Unit 2: The Living World - Biodiversity Flashcards
Ecosystem services
The process by which life-supporting resources, such as clean water, timber, fisheries, and agricultural crops are produced
Environmental indicators
An indicator that describes the current state of an environmental system
Five global-scale environmental indicators
○ Biodiversity
○ Food production
○ Average global surface temperature and carbon dioxide concentration in the atmosphere
○ Human population
○ Resource depletion
Biodiversity
The diversity of life forms in an environment
3 scales of biodiversity
- Ecosystem
- Species
- Genetic
Genetic diversity
- A measure of the genetic variation among individuals in a population
○ Populations with a high genetic diversity are better suited to respond to environmental change
Species diversity
- The number of species in a region or in a particular ecosystem
○ Higher species diversity causes more resilience to environmental changes and are more productive
○ Critical environmental indicator
Speciation
The evolution of a new species
Background extinction rate
The average rate at which species become extinct over the long term
Ecosystem diversity
- A measure of the diversity of ecosystems that exist in a given region
○ A greater number of healthy and productive ecosystems results in a healthier environment overall
Species’ richness
- The number of species in a given area
○ Used to measure biodiversity in a given area
Species’ evenness
- The relative proportion of individuals within the different species in a given area
○ Tells us whether a particular ecosystem is numerically dominated by one species or whether all of its species have similar abundances
Phylogeny
- The branching pattern of evolutionary relationships
○ Can be described with a diagram
Microevolution
Evolution below the species level
Macroevolution
Evolution that gives rise to new species, genera, families, classes, or phyla
Mutation
- A random change in the genetic code produced by a mistake in the copying process
○ Mutations can affect an organism’s survival and make their chances better or worse
Recombination
- The genetic process by which one chromosome breaks off and attaches to another chromosome during reproductive cell division
○ Does not create new genes but brings together new combination of alleles on a chromosome and therefore can produce novel traits
Artificial selection
The process in which humans determine which individuals breed, typically with a preconceived set of traits in mind
Natural selection
The process by which the environment determines which individuals survive and reproduce
Gene flow
- The process by which individuals move from one population to another and thereby alter the genetic composition of both populations
○ Alters the frequency of alleles in populations
○ Can bring in genetic diversity to a population that lacks it
Genetic drift
A change in the genetic composition of a population over time as a result of random mating
Bottleneck effect
- A reduction in the genetic diversity of a population caused by reduction in its size
○ When a population is reduced, its genetic diversity reduces as well
○ Can causes individuals to be less equipped to face environmental problems, disease, or low fertility
Founder effect
A change in the genetic composition of a population as a result of descending from a small number of colonizing individuals
Intinsic values
Values independent of any benefit to humans
Instrumental value
Worth as an instrument or a tool that can be used to accomplish a goal
Provisions
A good that humans can use directly to support life
Regulating services
Natural ecosystems help to regulate environmental conditions
Support systems
- Natural ecosystems provide several support systems that would be very costly for humans to generate
○ Ex: The pollination of food crops and natural pest control services
Resilience
- Ensures an ecosystem will continue to exist in its current state
○ Depends greatly on species diversity
Cultural services
Ecosystems provide beauty that many people are willing pay for
Theory of island biogeography
- A theory that demonstrates the dual importance of habitat size and distance in determining species richness
○ Depends on habitat size and distance from mainland
Range of tolerance
The limits to the abiotic conditions that a species can tolerate
Fundamental niche
The suite of abiotic conditions under which a species can survive, grow, and reproduce
Realized niche
The range of biotic and abiotic conditions under which a species actually lives
Distribution
- Areas of the world in which a species lives
○ Realized niche helps us understand the distribution of a species
Niche generalist
- A species that can live under a wide range of abiotic or biotic conditions
○ Fare better under changing conditions
Niche specialist
- A species that is specialized to live in a specific habitat or to feed on a small group of species
○ More vulnerable to extinction from habitat changes
Mass extinction
- A large extinction of a species in a relatively short amount of time
○ 5 mass extinctions have occurred over Earth’s history
6th mass extinction
During the last 2 decades, scientists have stated that we are currently experiencing a sixth mass extinction of a magnitude within the range of the previous 5 mass extinctions due to human activities
Geographic isolation
Physical separation of a group of individuals from others of the same species
Allopatric speciation
The process of speciation that occurs with geographic isolation
Reproductive isolation
The result of two populations within a species evolving separately to the point that they can no longer interbreed and produce viable offspring
Sympatric speciation
The evolution of one species into two, without geographic isolation
Polyploidy
The heritable condition of possessing more than two complete sets of chromosomes
