Biodiveristy
the variety of life in the world or in a particular habitat or ecosystem. Three types: ecosystem, species, genetic
species biodiversity
represents the number of different species living in an area
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Biodiveristy
the variety of life in the world or in a particular habitat or ecosystem. Three types: ecosystem, species, genetic
species biodiversity
represents the number of different species living in an area
genetic biodiversity
the total number of genetic characteristics in the genetic makeup of a species (higher gen. biodiversity makes populations more resistant to disturbance)
ecosystem biodiversity
refers to the variety of ecosystems found in a given area
habitat
the natural home or environment of an animal, plant, or other organism.
Ecosystem
A biological community of interacting organisms and their physical environment. (abiotic + biotic)
specialist species
Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food. (pandas)
generalist species
Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. (cockroaches, mice, rats, and human beings)
biodiversity hotspots
Relatively small areas of land that contain an exceptionally high number of species and are at high risk from human activities
ecosystem services
Important environmental benefits, such as clean air to breathe, clean water to drink, and fertile soil for growing crops, that ecosystems provide (have a monetary value to humans)
provisioning services
Benefits of biodiversity that humans use, including lumber, fur, meat, crops, water, and fiber
regulating services
the service provided by natural systems that helps regulate environmental conditions (trees removing carbon from atmosphere and roots filtering ground water)
supporting services
the basic ecosystem processes, such as nutrient cycles and soil formation, that are needed to maintain other services like agriculture (bees, moths pollinating agricultural crops)
cultural services
ecosystems provide cultural or aesthetic benefits to many people (tourists willing to pay to visit nature, or scientists conducting research that leads to new knowledge)
Anthropogenic
caused by humans
ecological
relating to or concerned with the relation of living organisms to one another and to their physical surroundings.
island biogeography theory
explains how species come to be distributed among oceanic islands
limited resources
the condition of there not being enough resources to fulfill the needs of all organisms in a given area (food, shelter, water)
invasive species
plants and animals that have migrated to places where they are not native. often outcompete natives (zebra mussel, asian carp, kudzu vine)
native species
Species that normally live and thrive in a particular ecosystem
Zebra Mussel
a small freshwater mollusk with zigzag markings on the shell. Introduced to US by large ships traveling over from Europe. Reproduce rapidly and outcompete natives for algae (food source)
Colonization
The process of a species migrating to a new habitat such as an island
generalist species
Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. Examples are flies, cockroaches, mice, rats, and human beings. .
specialist species
Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food. Example: panda
population density
The number of individuals in an area of a specific size (# of individuals/area unit)
K-selected species (K-strategists)
Species that tend to be large, have few offspring, invest lots of time and energy caring for offspring, take a long time to mature, and have long lifespans. (most mammals)
r-selected species (r-strategists)
Species that tend to be relatively small, have many offspring, invest minimal energy and time caring for offspring, mature early, have short lifespans. (most reptiles, amphibians, and insects)
biotic potential (intrinsic growth rate)
The maximum rate at which a population could increase under ideal conditions (like unlimited food & space)
survivorship curve
Graph showing the number of survivors in different age groups for a particular species.
Type I survivorship curve
most individuals survive infancy, live out their life span, and eventually die of old age (e.g., humans).
Type II survivorship curve
individuals die at a constant rate throughout throughout their lifetime (e.g., birds, rodents).
Type III survivorship curve
most individuals die young, with only a few organisms surviving long enough to reproduce and beyond. (oysters, plankton, insects, lots of plants)
J-shaped curve (exponential growth)
Growth where there is unlimited resources and no competition. Population grows without limit
S-shaped curve (logistic growth)
Growth where there are limited resources and the population eventually reaches a carrying capacity
cohort
A group of individuals of the same age. (ex: males 0-5 years old)
Overshoot
when a population becomes larger than the environment's carrying capacity
die-off/dieback
rapid population decline usually experienced after the overshoot of the carrying capacity
causes of dieback
overshoot, famine, drought, disease
carrying capacity (k)
the limit of how many individuals in a population a given ecosystem can sustain (due to limited resources such as food, shelter, water, etc.)
population growth rate
how fast a specific population grows in a specific period of time (births-deaths/total population size)
density dependent factors
limiting factors of population growth that depends on population size (competition for food, limiting nutrients, water, space, mates, etc.)
density independent factors
events that limit population growth regardless of their size (natural disasters like fires, tornados, floods, etc.)
sex ratio
the ratio of males to females in a population. skewed sex ratios (too many males, not enough females) can slow population growth
doubling time
the time required for a population to double in size. calculated by 70/growth rate (70/2% growth rate = 35 years to double)
ecological tolerance
The ability of a species to survive and reproduce under a range of environmental circumstances (generalists are more tolerant compare to specialists)
range of tolerance
Range of chemical and physical conditions that must be maintained for populations of a particular species to stay alive and grow, develop, and function normally
natural disturbances/disruptions
all natural events that destroy or damage an ecosystem; fires, hurricanes, tornadoes, droughts, floods
anthropogenic disturbances/disruptions
Human-caused disturbances to ecosystems. Often negatively impacts biodiversity. Timber harvesting, pollution, overgrazing, introducing invasive species, and development.
periodic
describes an event that occurs or repeats at regular intervals (seasons, night & day)
episodic
describes an event that happening in parts or segments or that kicks off a flow of related events (eutrophication, overhunting by humans)
random
something that occurs randomly (hurricanes, lightening strikes, etc.)
migration
Movement of organisms from one habitat to another. Sometimes permanent (when their habitat is destroyed or disturbed) or temporary (for mating, feeding, or seasonal reasons)
sea level
The average level of the ocean's surface at any given time. Has changed significantly over time based on amount of glacial ice and polar ice.
geologic time scale
scale used by paleontologists to represent evolutionary time
resistance
measure of how much a disturbance can affect the flow of energy and matter in an ecosystem. ecosystems with high resistance are not as vulnerable to natural and anthropogenic disturbances
resilience
the rate at which an ecosystem returns to its original state after a disturbance. the more resilient, the faster an ecosystem returns to its normal state after a disturbance
Adaptation
A characteristic that improves an individual's ability to survive and reproduce in a particular environment.
genetic diversity
a measure of the genetic variation among individuals in a population (higher gen. diversity leads to greater rate of evolution)
Genotype
An organism's genetic makeup
Phenotype
An organism's physical appearance, or visible traits.
natural selection
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. Leads to evolution of new traits (microevolution) and new species (macroevolution)
Evolution
Changes in a species over time driven by natural selection. Can lead to new traits or entirely new species. INDIVIDUALS DO NOT EVOLVE. SPECIES EVOLVE.
Speciation
the formation of new and distinct species in the course of evolution.
Species
A group of similar organisms that can breed and produce fertile offspring. Different species cannot breed with each other.
reproductive isolation (sympatric speciation)
Differences in behavior or morphology that prevent organisms from breeding with each other (diff. mating calls in birds or diff. structures in flowers in plants)
geographic isolation (allopatric speciation)
two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water. this prevents them from breeding with each other and leads them to evolve into different species
ecological succession
gradual change in living communities that follows a disturbance
primary succession
succession that occurs on surfaces where no soil exists (bare rock being colonized by moss & lichen, broken down into soil, & eventually colonized by grasses and shrubs)
secondary succession
Succession following a disturbance that destroys a community without destroying the soil (often times a fire or windstorm)
pioneer species
Hardy, first species to populate an area during primary or secondary succession (moss & lichens, small grasses, shrubs, and small trees)
climax species
species that move into an area at later stages of ecological succession. slower growing, species that include large tree
keystone species
A species that has an unusually large effect on its ecosystem. It influences the survival of many other species in an ecosystem, often by creating habitats (beavers) or controlling herbivores (wolves)
indicator species
Species that serve as early warnings that a community or ecosystem is being degraded. (think of the canary in the coal mine)