A powerpoint reprsents the aquatixe environment and it history.

1. THE NATURAL HISTORY OF AQUATIC
ENVIRONMENTS

2. AQUATIC
ECOSYSTEM
An aquatic ecosystem is an ecosystem in a body of water. Communities of
organisms that are dependent on each other and on their environment live
in aquatic ecosystems.
TYPES *The two main types of aquatic ecosystem are marine ecosystems
and freshwater ecosystems.
MARINE ECOSYSTEM
 Are aquatic ecosystems whose waters possess a high salt content.
 Out of all of the types of ecosystems on the planet, marine ecosystems
are the most prevalent.
 They teem with life, providing nearly half of the Earth`s oxygen and a
home for a wide array of species.
 Examples for marine ecosystem includes salt marshes, intertidal zones,
estuaries, lagoons, mangroves, coral reefs, the deep sea, and the sea
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3. FRESHWATER ECOSYSTEM
 Cover 0.80% of the Earth`s surface and inhabit 0.009% of its total water.
Freshwater contain 41% of the world`s known fish species.
 Theses have low level of salt content when compared to marine ecosystem.
There are three basic types of freshwater ecosystems:
 LENTIC – they are slow moving waterbodies like ponds, and lakes. Lentic
refers to stationary or relatively still freshwater, from the Latin lentus,
which means “sluggish”.
*LITTORAL ZONE – is the shallow zone near the shore. This is where
rooted wetland plants occur. The offshore is divided into two zones:
OPEN WATER ZONE, sunlight supports algae and the species that feed
upon them. DEEP WATER ZONE, sunlight is not available and the food
web is based on detritus entering from the littoral and photic zones.
*BENTHIC ZONE – bottom area of lake or pond consisting of
decomposers, larvae of insects, and clams.
 LOTIC – they are faster moving waterbodies like stream and rivers. From
the Latin lotus, meaning washed.
 WETLANDS – they are the areas where the soil is saturated or inundated
for some of the time. There are four main types of wetlands: swamp, marsh,
fen, and bog.

4. FUNCTION
Aquatic ecosystems perform important environmental functions. They recycle
nutrients, purify water, attenuate floods, recharge ground water and provide habitats
for wildlife. Aquatic ecosystems are also used for human recreation and very
important to the tourism industry, especially in coastal regions.

5. CHARACTERISTICS:
ABIOTIC CHARATERISTICS – some of the
important abiotic environmental factors of aquatic
ecosystems include:
 Substrate type
 Water depth
 Nutrient levels
 Temperature
 Salinity
 Flow
 Dissolved oxygen
 Nutrient levels

6. BIOTIC CHARATERISTICS – are mainly determined by the organisms that
occur. Wetland plants may produce dense canopies that cover large areas of
sediment. And snails or geese may graze the vegetation leaving large mud flats.
These biotic factors can be classified into three groups:
 Producer, aquatic plants like algae, volvox, Closterium, hydrilla, and so on.
 Small animal which depends on plants for their food are primary consumers,
also the one who eats the primary consumers can be called, either secondary or
tertiary consumer.
 Decomposers, like bacteria, fungi, and other microorganisms decomposes the
dead bodies and mix it to the soil which acts as the nutrients of producer.

7. POPULATION GENETICS
• Population genetics is the
study of change in the
frequencies of allele and
genotype within a population.
• Population geneticists study
the genetic structure of
populations, and how they
change geographically and
over time.
• Gene – a discrete unit of
hereditary information
consisting of a specific
nucleotide sequence in DNA.
• Alleles – alternative forms of
a gene.
• Genotype – the genetic
makeup of an individual.
• Phenotype – the physical
traits of an organism.
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8. WHY ALLELE FREQUENCIES CHANGE
• Five evolutionary forces can significantly alter the allele frequencies of a population
MIGRATION
• Movement of
individuals from one
population to another
- Immigration:
movement into a
population
- Emigration: movement
out of a population
• A very potent agent of
change
MUTATION
• Errors in DNA
replication
• The ultimate
source of new
variation.

9. WHY ALLELE FREQUENCIES CHANGE
• Five evolutionary forces can significantly alter the allele frequencies of a population
NONRANDOM
MATING
• Mating that occurs more
or less frequently than
expected by chance
- Inbreeding: mating with
relatives and increases
homozygosity
- Out breeding: mating
with non-relatives and
increases heterozygosity.
GENETIC DRIFT
• Random loss of
alleles
- Founder Effect: small
group of individuals
establishes a
population in a new
location.
- Bottleneck Effect: a
sudden decrease in
population size to
natural forces.

10. WHY ALLELE FREQUENCIES CHANGE
• Five evolutionary forces can significantly alter the allele frequencies of a population
SELECTION
• Some individuals leave
behind more offspring than
others.
- Artificial selection:
breeder selects for desired
characteristics
- Natural selection:
environment selects for
adapted characteristics

11. TYPES OF VARIATION
Phenotypic variation – it`s a genetical basis morphological variation its some tie
continuous and sometimes discontinuous. Example: salmonberry and two-spotted
ladybird beetle

12. TYPES OF VARIATION
Genetic variation – the variance that is due to variation among individuals in the
alleles that they have, excludes environmentally-caused variation.
Natural selection – is a process by which heritable traits that makes it more likely
for an organisms to survive and successfully reproduced become more common in
population over successive generation.

13. FORMS OF SELECTION
Three types of natural selection have been identified:
• Stabilizing selection: acts to eliminate both extreme phenotypes
• Disruptive selection: acts to eliminate intermediate phenotypes
• Directional selection: acts to eliminate a single extreme phenotype

14. THANK YOU!
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