ecosystem diversity

7/28/2019 Ecosystem Diversity

1/12

Ecosystem Diversity


2/12

Ecosystem

An ecosystem is a communityplus the physical environmentthat it occupies at a giventime. An ecosystem can existat any scale, for example, fromthe size of a small tide pool upto the size of the entirebiosphere. However, lakes,marshes, and forest standsrepresent more typicalexamples of the areas that are

compared in discussions ofecosystem diversity.


3/12

What Is Ecosystem Diversity?


4/12

Biodiversity

Biodiversity is the degree of variationof life forms within a given species,ecosystem, biome, or anentire planet. Biodiversity is a

measure of the health ofecosystems. Biodiversity is in part afunction of climate. In terrestrialhabitats, tropical regions aretypically rich whereas polarregions support fewer species.


5/12

Evolution

Evolution is the change in the inheritedcharacteristics of biological populationsover successive generations.

Evolutionary processes give rise to

diversity at every level of biologicalorganisation,including species, individualorganisms and molecules suchas DNA and proteins Charles Darwin was

the first toformulate a scientificargument forthe theory of

evolution by meansof natural selection.


6/12

Types Of

Evolution

Heredity

Evolution in organisms occurs through changes in

heritable traits particular characteristics of an organism.

Heritable traits are passed from one generation to the nextvia DNA, a molecule that encodes genetic information.

Variation

An individual organism's phenotype results from bothits genotype and the influence from the environment it has lived in.A substantial part of the variation in phenotypes in a population is

caused by the differences between their genotypes. The frequencyof one particular allele will become more or less prevalent relative

to other forms of that gene. Variation disappears when a new allele

reaches the point of fixation when it either disappears from thepopulation or replaces the ancestral allele entirely.


7/12


8/12

Natural Selection

Natural selection is the gradual, non-random processby which biological traits become either more or less

common in a population as a function of differential

reproduction of their bearers. It is a key mechanismof evolution.

Variation exists within all populations of organisms.

This occurs partly because random mutations cause

changes in the genome of an individual organism,

and these mutations can be passed to offspring.Throughout the individuals lives, their genomes

interact with their environments to cause variations intraits. (The environment of a genome includes

the molecular biology in the cell, other cells,

other individuals, populations, species, as well

as the abiotic environment.)

Natural selection isone of the basicmechanisms ofevolution, along with

mutation, migration,and genetic drift.

D i ' d id f


9/12

Darwin's grand idea ofevolution by natural selectionis relatively simple but often

misunderstood. To find out howit works: Here is an Explanation

1.There is variation in traits.For example, some beetles are green and someare brown.

2. There is differential reproduction.Since the environment can't support unlimited

population growth, not all individuals get to reproduce totheir full potential. In this example, green beetles tend toget eaten by birds and survive to reproduce less oftenthan brown beetles do.

3.There is heredity.

The surviving brown beetles have brown baby beetlesbecause this trait has a genetic basis.

End result:The more advantageous trait, brown coloration, which allows

the beetle to have more offspring. If this process continues,eventually, all individuals in the population will be brown.


10/12

Ecosystem Services

Ecosystem Services are theprocesses by which theenvironment producesresources thatwe often take for granted such

as clean water, timber, andhabitat for fisheries, andpollinationof native and agriculturalplants. Whether we findourselves in the city or a rural

area, theecosystems in which humanslive provide goods andservices that are very familiarto us.


11/12

Ecosystems provide services that:

moderate weather extremes and their impacts disperse seeds mitigate drought and floods protect people from the suns harmful ultravioletrays cycle and move nutrients

protect stream and river channels and coastalshores from erosion

detoxify and decompose wastes control agricultural pests maintain biodiversity generate and preserve soils and renew

their fertility contribute to climate stability purify the air and water regulate disease carrying organisms pollinate crops and natural vegetation


12/12

Thats All

Thank You!!

ecosystem diversity

Documents