- developed by darwin, published first in book "Origin of species" (1859) - there is physical/behavioral variations in living organisms, even within the species level (genetic) - higher fitness= more likely to reproduce

unit 2 Flashcards by Olivia Varghese

natural selection

developed by darwin, published first in book “Origin of species” (1859)
there is physical/behavioral variations in living organisms, even within the species level (genetic)
higher fitness= more likely to reproduce

How well did you know this?

Not at all

Perfectly

The range of different inherited traits within a species

genetic diversity
**The more genetic diversity a species has, the more RESILIENTit is; it has more “options” for response/adaptation to occur if the environment changes

How well did you know this?

Not at all

Perfectly

the number of different species present in an ecosystem and relative abundance of each of those species (takes into account species richness and species evenness)

Species Diversity
**The more species diversity there is; the more resilient that ecosystem is to changes

How well did you know this?

Not at all

Perfectly

the range of habitats where different species live (habitat→the natural home or environment of an animal, plant, or other organism)

habitat diversity
**When habitats are lost, specialist species are lost followed by generalist species and then species that require a lot of territory (space) are lost

How well did you know this?

Not at all

Perfectly

number of different species

species richness

How well did you know this?

Not at all

Perfectly

describes distribution of abundance (total number) across the species; it is high when all species have a similar number

species eveness

How well did you know this?

Not at all

Perfectly

broad niche
very adaptable
uses a variety of resources/different food
can be found around the world
high tolerance

generalist species

How well did you know this?

Not at all

Perfectly

narrow niche
limited diet
found in specific habitats
low tolerance
not adaptable

specialist species

How well did you know this?

Not at all

Perfectly

-alternative forms of a gene found at the same place on a chromosome; arise due to mutations

alleles
*-Different alleles⇒variation of traits

How well did you know this?

Not at all

Perfectly

A change in allele frequencies in a population from generation to generation
occurs due to chance events
can result in the loss of some alleles (even beneficial ones) and the fixation (rise to 100%) of others
Happens in populations of all size; effects are stronger in smaller populations

genetic drift (2 major processes are founder’s and bottleneck effect)

How well did you know this?

Not at all

Perfectly

-Occurs when a population is sharply reduced in size by a natural disaster (ex: earthquakes, floods, fires)

bottleneck effect

How well did you know this?

Not at all

Perfectly

-A small group splits off from the main population to found a colony (ex: islands, habitats cut off due to urbanization)

founder’s effect

How well did you know this?

Not at all

Perfectly

. Over time, a natural selection will ensure that certain characteristics appear more and more often as they are passed through generations. Entire species can change over time in this way.

How well did you know this?

Not at all

Perfectly

Genes for new traits have to ALREADY BE PRESENT in a population’s gene pool through random mutation.
Our generation times are too long to keep up with rapidly changing conditions
*specifically for humans, human evolution takes thousands of years

why can’t organisms evolve immediately to adapt to current changes

How well did you know this?

Not at all

Perfectly

“Fitness” means strongest, fastest, or biggest.
Organisms develop new traits in order to help them in their environment.
Evolution is a constant progression towards some perfect ideal.

myths about evolution

How well did you know this?

Not at all

Perfectly

locations of continents influence climate and habitats
movement of continent allow for DISPERSAL, SPECIATION, AND EXTINCTION

geological processes affecting population

How well did you know this?

Not at all

Perfectly

ex. earthquakes can isolate populations, leading to speciation
volcanoes can destroy habitat and can extinction
asteroid impact can cause widespread extinction and climate change
ice ages/warming periods can cause migration, extinction, new niches

geological and climate change impact on evolution

How well did you know this?

Not at all

Perfectly

Islands that are larger and closer to the mainland have HIGHER species richness

island biogeography

How well did you know this?

Not at all

Perfectly

The edges slowly degrade due to wind, invasion of species, and increased sunlight. Degradation of edges can lead to habitat fragmentation.
Some species may become more susceptible to predators because of decreased protection from the forest.

Selective logging causes caps in the canopy thus causing an edge effect.
(In ecology, edge effect refers to changes in a population or community along the boundary of a habitat. A clear example of this is when an agricultural field meets a forest)

Habitat fragmentation cuts species off from larger populations thus causing inability to support viable populations.

Tropical Rainforest soil is low in nutrient quality approximately 10x more land is needed for grazing animals and the previously cleared agricultural land is abandoned to clear nearby forest to further grow crops.
**Millions of Brazilian Amazon Rainforest are destroyed every year due to human set forest for agricultural use and by ranchers.

Clear cutting for agriculture and pastures.

there is an increase in:
- diversity and population numbers
- system stability
- biomass
- nutrient hold capacity

as ecosystems mature…

reproduction
clearing out competitors
germination (seed sprouting)

what is fire succession in chaparral (shrubplant community) used for

primary succession= no previous life, exposed rock
secondary succession= already formed land, land on disturbed material
sucession = communities change over time

-Variability in genetic makeup among individs in a pop. -If too few DNA differences 🡪 genetic bottleneck 🡪extinction.

genetic diversity

- mass hunting - natural disaster - loss of food - introduction of non-native/invasive species -

causes of bottleneck effect

Transitional zone where 2 or more communities meet 🡪 HIGH BIODIVERSITY EX. INTERTIDAL ZONES

ecotone

Habitat stress -Available niches -Dominance of species -Geological history

factors that determine SPECIES DIVERSITY

Considered separate species if they cannot interbreed Same species create viable offspring

species

ex. of a pioneer species: Lichens: Can be N fixers 🡪 Put Nitrate into soil for other plants to grow! Can also measure air poll - moss is also a good pioneer species - species after the pioneer species include: grasses/small plants, then smaller shrubs, then trees

ecological services --> !!!!!!!!!!!NATURAL !!!!!!!!!!!!!!!!!!!! - provisioning--> "stuff" (matter) ex. water, lumber, food - regulating v. supporting - supporting = without these, others couldn't exist ex. nutrient cycling, photosynthesis, soil formation, - regulating--> water quality and air quality (BIG PICTURE) - cultural--> religion, aesthetic/beauty, recreations

An intact coastal wetland or marsh would offer natural protection from hurricane storm surges categorized under regulating ecosystem service. Coastal wetlands buffer against waves by slowing them down before they reach your property, and they help to drain floodwaters after a storm.

low habitat diversity= likely a lower numbr of specialist spcies and few species that utilize larger territories

Having a limited number of different habitats would inhibit the survival of different types of specialist species and those that control large territories.

relation of low species diversity to different species

"stuff” (matter) ex. water, lumber, food, wood fuel, natural gas, oil, medicinal resources,etc - any type of benefit to people that can be extracted from nature

provisioning

without these, others couldn’t exist ex. nutrient cycling, photosynthesis, soil formation,

supporting

water quality and air quality (BIG PICTURE) - benefit provided by the ecosystem that moderates "natural phenomena" - processes work together to make ecosystems clean, sustainable, functional, and resilient to change

regulating

changes in a population or community along the boundary of a habitat. A clear example of this is when an agricultural field meets a forest)

edge effect

religion, aesthetic/beauty, recreations - non material benefit, contributes to development and advancement of people - how ecosystems play a role in local/national/global cultures

cultural

- burning fossil fuels - deforestation - industrial agriculture - overfishing - pesticide use - genetically modified crops - water pollution

ex. of anthropogenic activities

- acid desposition= pH of water and climate disruption - loss of species and habitat - monocropping - loss of species - loss of genetic variation - loss of aquatic habitat diversity

biodiversity impact from anthropogenic activities

esources that are present in excess of an organism’s tolerance or in insufficient quantities to meet basic needs of organism. !!!!!!An organism’s size, age, state of health, or DNA can influence their range of tolerance.!!!!

!!!!The optimal range is the amount of an ABIOTIC FACTOR that produces the HIGHEST POSSIBLE POPULATION.!!!! For water temperature, this would be about 6-10°C.

optimal

The zone of physiologic stress occurs when an abiotic factor exists at levels that are too high or low to support normal biotic potential. This would be 3-6°C and 10-16°C.

The zone of physiologic stress

The zone of intolerance occurs when a population is ABSENT (or in this case, nearly absent). This occurs at either extreme of our water temperature graph, below 3°C and above 16°C.

zone of intolerance

Lichens and pioneer species secrete acid onto rocks causing chemical weathering

Edges of forests considered ecotones