BIODIVERSITY Flashcards
what is biodiversity
the variety of life in a particular habitat or ecosystem
- genetic diversity / number of species / number of broad classes of organisms
what is habitats
the environment in which an organisms lives (living and nonliving elements)
whats habitat diversity
the different kinds of habitats in a given unit of area
what is species richness
total number of species
what is species evenness
relative abundance of species making up the richness of an area e.g. how many of one species compared to another
what is species dominance
the most abundant species
whats the Number of Species on Earth
1.8 million species have been identified
* Estimated that 8.7 million species currently exist
* 86% of all species on land and 91% of all marine species have not been identified
what is Species diversity
The number (or evenness) of species within an
ecosystem or on the entire planet
whats the correlation with species diversity and resilience
Correlated - species diversity increases resilience
Diversity also increases productivity
2 groups we can divide organisms into
Specialist + Generalist
whats a specialist species
– Narrow niche
– Specific requirement
– May be less resilient to environmental changes
whats a generalist species
– Have broad niches + diets
– Advantage when environmental condition change
- generally more resilient
whats genetic diversity / variation
total number of genetic characteristics of a specific species, subspecies, or group of species
- diverse population has a greater ability to withstand environmental variability
what are alleles
different forms of the same genes, determine
various genetic features/phenotypic traits
whats a genotype
the genetic makeup of a cell, an organism,
or an individual
whats a phenotype
the outward appearance of an organism;
the expression of a genotype in the form of traits that
can be seen and measured e.g. hair or eye color, or disease resistance
3 ways populations can be distributed
- uniform - Equal distances from each other
Compete for space
Defend territories - random - No pattern
Resources are plentiful - clumped - Unevenly spaced
Aggregations around resources
whats a home range
the area in which an animal lives and travels
whats a Endemism/ Endemic Species
a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type e.g. Australia - kangaroos
Factors that tend to increase diversity
– A physically diverse habitat
– Moderate amounts of disturbance
– A small variation in environmental conditions
– High diversity at one trophic level increases the
diversity at another trophic level
– An environment highly modified by life (e.g. rich soil)
– Middle stages of succession
– Evolution
Factors that tend to decrease diversity
– Environmental stress
– Extreme environments
– A severe limitation in the supply of an essential
resource
– Extreme amounts of disturbance
– Recent introduction of exotic species (species
from other areas)
– Geographic isolation (being on a real or ecological
island)
whats a A biotic province based on
who is related to whom – An evolutionary unit
whats a biome based on
niches and habitat
– If we know the climate we can make predictions
about the biome
whats a biotic province
a region inhabited by a characteristic set of taxa,
bounded by barriers that prevent emigration and immigration
- In each biotic province certain families of animals are dominant and fill ecological niches e.g. South America – capybara
- species are more likely to be related - Evolved and adapted in the same place for a long time
-
whats the 6 biogeographic regions
Nearctic, Neotropical, Palaearctic, Ethiopian, Oriental,
Australian
how does species diversity vary globally
tends to decrease from the tropics to the poles
hy[othesis on why species diversity tends to decrease from the tropics to the poles
– Greater primary productivity in the tropics
– Stronger (and more permanent) habitat gradients
due to decreased seasonal variability
– Ecosystem complexity: Tropical forests have
multiple canopy layers, which each provide a suite
of niches (similar to coral reef ecosystems)
what are biodiversity hotspots
places that have an unusually large number of endemic species
whats a Endemic species
a species that is unique to a defined geographic location (e.g. it’s not found elsewhere)
– Unique habitats, topographic diversity, isolation
Island biogeography
– Fewer species than continents
– Two new sources of species: migration and
evolution
– Smaller the island, the fewer the species
– The farther away from a continent, the fewer the
species
– Islands tend to maintain consistent number of species over time
what is functional biodiversity
the total amount of roles that are filled within an ecosystem
what is Functional redundancy
species that fill similar niches can replace each
other if one goes extinct
How did biological diversity come about
evolution
– Charles Darwin (19th century)
– Explanation of diversity known as biological evolution = Change in inherited characteristics
of a population from generation to generation (appearance and behavior)
Four processes lead to evolution
- Natural Selection
- Mutation
- Migration
- Genetic drift
what is natural selection
primary mechanism of evolution
- Traits that enhance survival and reproduction are
passed to future generations
- Those better able to survive and reproduce leave more offspring, forming the larger proportion of the next generation
- may result in new species
what is mutation
when an error occurs in the reproduction of DNA as it gets passed to new cells
– Possible causes – radiation, chemicals or a virus
- possible effects = offspring cannot survive, adds to genetic variability
what is Adaptive radiation
organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment
makes new resources available, creates new challenges and opens environmental niches
whats genetic drift
Changes in frequency of a gene in a population simply by chance
whats the founder effect
Small number of individuals are isolated form a larger population
* Less genetic variation than original population
- Characteristics present are affected by chance
– Individuals may NOT be better adapted
what does Biological evolution tell us about biodiversity
Species present in any one location can change over time and can become geographically isolated from time to time, and undergo the founder effect and genetic drift
what is Divergent Evolution
– Organisms have a common ancestor
– Population is divided and each evolves separately
– May look and act differently but they are still
related
what is Convergent evolution
– Organisms have similar features but they don’t
have a common ancestor
– given sufficient time and similar climates species
similar in shape and form will tend to appear
– May look and act the same but they are not
related
e.g. gliding capabilities of flying squirrels and flying lemurs
how do people alter biodiversity
– Direct hunting
– Directly disturbing habitats
– Introducing exotic species into new habitats
– Altering the habitat indirectly (e.g. climate change)
– Artificial selection (is the intentional breeding of plants or animal and selecting for specific traits)
