Theme A: Unity & Diversity Book Concept- Binomial...-Selection

Diversity of Organism

Species

a group of individual of common ancestry that closely resemble each other and that are normally capable of interbreeding to produce fertile offspring.

Controversy of Ernst Mayer Defintion

• Asexual Organisms: have one parent and do not reproduce with eachother (bacterias.. but still are same species)

• Some species can reproduce with similar species, thus forming hybrids

  • zebras and horses

General forms of classification

Generally classified through morphology back in the day. Carol Linnaeu made system and used both of binomial and observation- Swedish Botanist

1. By-habitat: land-dwelling aquatic

2. By eating habits : whether it is carniovre or herbivore

3. By movement: sessile (stuck or moves)

4. Daily activity: nocturnal or diurnal

5. By risk: poisonous not poisonous

6. By anatomy: intervertebral or vertebrae

Binomial Nomenclature

Dear Kevin Please Come Over For Good Spaghetti (From Generic (D) to Specific (S) )

Taxonomy: naming of organisms

Domain, Kingdom, Phylum, Order, Family, Genus, Species,.

Binomial Nomenclature Rule

1st name is a latin noun and is always capitalized refers to genus as in general “Homo”

2nd name is a adjetive no capital refers to species and is underlined in writing “Homo sapiens”

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Genus

(Brand of a car) Indicated a group of species that are very closely related and share a common ancestor

A group of similar and closely related species

Species

Various definitions for species exist but it is a group of organism with shared trait (can interbreed)

Benefit of Classification System

1. each organism had a unique and specific name thus it cannot be confused with another

2. added stability as scientists cannot change the name of the organism without an valid reason

3. names are universally understood regardless of nationality, culture, and language

Biological Species Concept

Made by Ernst Mayer

• to be classified as same species, the organism must be capable of interbreeding and producing fertile offspring.

• helps in cases of sexual dimorphism where male and female look significantly different

Cons

• asexually reproducing organisms: bacteria and hybrids are not always infertile like zebras and horses

• extinct species: fossil record cant determine whether able to interbred.

Different Arguments about Species

1. For microbes or single-celled organisms, one cannot utilize morphology. so must look at function

2. one can look into what type of molecule organism can produce when not physically observable features

3. for fossils, can use similarities to others to assign its species name position and classification.

Continous Variation

Wide range (no specificity) height

• variation at any value of measurement for a specific characterstic like height

  • controlled by pollygenes: weight and height

Discontinous Variation

Specific variables or distinct categories like Blood: A, B, AB, O..

• a continuum of variation from one phenotype to another like human height

Some variations are not continous, they are discrete like blood type

• discontinous variation is variation that has two distinct groups that organisms belong to

• no form or overlap between two phenotypes

• Characteristics that show this are controlled by one gene, that has usually two alles (human system has 3).

Variation

Differences between individuals of a species. May be caused by genetic and environmental factors

• this creates diversity

Condtion can affect (appearance) of organisms

Altering physiology of individuals affects continous variations. Tall plant may be dwarf but also consistently deprived of adequate essential mineral oils.

Phenotype

Product of both its genotype and influence of environment

Discontinous Variation can be caused

Effect in mutation or development, like homeotic mutations that cause discret changes in form of single mutuation (Loss of one pair of wings,)

morphology

form and structure of an organism

allele

alternative form of a gene that occupies a specific locus on a chromosome

Homeotic Mutuation

alteration in genes that determine the type or location of a body part during an organisms development

Morphological Species Concept

Original system for classyfying species which was based on appeareance and traits. Criticized but useful for plants

• can be applied to asexual and sexual organisms

• does not require info on gene flow

• can be applied to extinct fozzilised species

• easiest and fastest way to identify based on appearance

but

• subjective scientists may disagree

• individuals may appear different such as males and females (sexual dimorphism)

Sexual Dimorphism

differences in appearance between males and females of the same species, such as in colour, shape, size and structure.

Idea of Morphological Species Concept

species are groups of organisms with shared traits.

Species concept:

a working definition of a species and a methodology for determining whether two organisms are members of the same species.

Taxonomy

Taxon: classificatory grouping, general name for groups with classification system

The science of classification

Define Binomial System

Double names for organisms, in Latin with generic name preceding scientific name

Biological Species Concept

Created by Ernst Mayer

• a species is a group of organisms that can breed and produce fertile offspring

Limitations to Biological Species Concept

• not apply to organisms that reproduce asexually all or most of the time like prokaryotes

• does not apply to organisms that are extinct

• overemphasizes gene flow and downplays the role of natural selection, as natural selection can cause many pairs of species that are morphologically and ecologically distinct to remain distinct and yet have gene flow between them

Ecological Species Concept

alternative to morphological species concept

• species is a group of organisms that is adapted to a particular set of resources; this concept explains differences in form and behaviour between species as adaptations to resource availability.

• defines a species according to their ecological niche

• for ex, two species of finches on the Galapagos islands may be similar in appearance but distinguishable based on what they feed on

Advantages of Ecological Species Concept

• can accomodate asexual as well as sexual species

• emphasizes the role of disruptive natural selection as organisms adapt to different environmental conditions

Limitations of Ecological Species Concept

Niche are generally difficult to identify because a niche involves the interaction between organism and its environment

Ecological Species Concept

Species is a group of organisms that is adapted to a particular set of resources (niche); this concept explains differences in form and behaviour between species as adaptations to resource avalability

Evolutionary species concept

A species is a single lineage of populations descending from a common ancestor, which maintain its identity from other such lineages and which has its own selection pressures and evolutionary outcome

• developed thanks to the ability to compare genetic sequences from different organisms to compare similarities and potential ancestry.

Population

interacting groups of organisms of the same species living in an area

Different Species Concepts

Speciation

when a population of same species divides into two groups causing that they can no longer reproduce together and thus form a new species

• caused by changes in chromosomes number, errors in cell division (produced twice), changes in the behaviour of reproduction cycle, reproductive barrier, physical barrier,

population

organisms are part of populations

• a group of individuals of same species, living close enough to be able to interbreed

• species live normally in localized populations, local population boundaries hard to define

• species from local population seem to resemble each other

Local population and speciation

They can be a starting point for speciation

• speciation is the name we give to the process by which one species splits into two or more species

  • process by which new species form where one splits into two or more. before they share a common gene pool, but after isolation their genes undergo mutations (just for one)

  • a new population can also occur from the one that seperated

  • smallest unit of evolution is population, populations can evolve.

Genetic Diversity

biological variation within species which allows for species to adapt.

• by studying chromosomes one can study genetic diversity

Chromosomes

thread-like structure that is narrow made of protein and a single molecule of DNA that serves to carry genomic info from cell to cell.

function: carry genes in a linear sequence that is shared by members of a species

made by DNA that is folded and histones that are wrapped around that have nucleaosomes which then are coiled until forming chromosomes

• between nuclear division, can replicate when uncoiled or are in the form of chromatin and can’t be seen (in cell cycle of interphase)

genome

total amount of genetic matierial in an organism or cell and is directly related to amount of DNA. or the collection of nitrogenous bases

• doesn’t increase due to being human or complexity

• genome size cant be reduced from number of chromosomes

• the # chromosome stays the same for species but (characteristic)

eukaryotic organisms vary due to a change of sequence or amount of DNA but not in DNA bases since code is conserved for all organisms- this allows unity all share same gene

genome

we all posses same genes, but not the same as some are called alleles

• between humans have a 0.4% difference

• while in chimpanzees and humans difference is 4% bigger- that tiny difference is Single Nucletoide Polymorphism (only one base pair)

# of Chromosome Per Species

chromosome diversity human 46 chimpanzee 48

centromere

somewhere along the length there is a narrow region called the centromere, which is an indent, that is always in same position regardless of being able to be anywhere

• position of centromere and length of chromosome allows scientists identify chromosomes in photomicrographs

• constriction of chromosomes, the region that becomes attached to spindle fibres during nuclear division

Diploid Nucleus (somatic)

Chromosome of a cell occurs in pairs called homologous pairs (cells has two sets of chrome)

• one of each came from male parent and another from female parent

  2n (n each chromosomes)

• Homologous chromosomes share the same sets of genes in the same order but sometimes their alleles are different. For example one chromosome may have the dominant allele for round seeds (R), while the other has the recessive allele smaller seeeds r.

• New formed by mitosis

Homologous

• Homologous chromosomes share the same sets of genes in the same order but sometimes their alleles are different. For example one chromosome may if heterozygous have the dominant allele for round seeds (R), while the other has the recessive allele (

• share same size and structure, share the same genes at locus locations

Homozygous alleles

having two identical alleles from a gene

Heterozygous

having two different alleles from a gene one dominant another reccesive (round seed R while other reccesive allele)

Haploid Nucleus (prokaryotic)

However for any organism to reproduce needs this cells. Cells having one set of chromosomes

n (sex cells)

• formed as a result of meiosis which is a form of nuclear division.

Alleles and Locus

chromosmes have a gene sequence, the position of a gene is a locus, and each gene has two or more forms called alleles

two alleles can carry same sequence of bases coding for identical protein. if they same allele carries same sequence of bases that code for identical proteins at the locus on both copies of homologous pairs is described as homozygous

if two different alleles . it is called heterozygous

Chromatids

are formed after replication

• chromatids remain attached by their centromeres until they are separated during nuclear division, once divided they are recognized as chromosomes again (this is very specific and copy DNA double helix that runs length, need special enzymes)

chromosome replication

Karyotype

number and type of chromosomes present in an organism which are seen during mitosis, at that stage each chromosome is present by two chromatids held together by a centromere

karyograms

photographs obtained by cell sample in which homologous chromosome are arranged in descending order of size (1-22 autosomes and last 23 X/Y sex chromosome or XX (sex chromsome), y being smaller (each chromosome replicayed and exists as chromatids held together by centromere)

Why karyograms

Through blood tests people can do prenatal test. This has various benefits as one can check number and appearance of chromosome to detect abnormalities like the duplication, translocation, absence, or deletion of a chromosome.

amniotic fluid and blood- help find abnormaliies and gender

karyotyping

isolating condensed chromosomes taken from actively dividing cells

• stain and highlight pattern if isolated at right time then two chrom copies are attached.

Karyotype Guide Analysis

Male: X longer than Y chromosome

Women: XX (23) same size

trisomy 21 (Down Syndrome)

Human Genome project

collection of all basses, scientists wanted to sort out all bases in cells, “map entire human genome”- publicly funded 1990 then achieved in 2000. did 200 labs

• help revise classification

• dtermine how many genes human hace

• ability to locate genes that cause genetic disorders

• develop bionformatic: storage manipulation of bio data

general evolution

change over time in the genetic composition of a population

• described culmulative changes that occur within population

• may change so much forms own species

• population may accumulate enough change that it constitutes a new species a new life form

Darwanism Evolution

change in heritable characteristics overtime in the genetic composition of a population (characteristics encoded by genes and transferred between generations as alleles)

• defines evolution as descent with modification

• current species are descendant of ancestral species

• the change in the genetic composition of a population from generation to generation.

Darwin Ideas

• nature tends to overproduce offspring then what the environment can hold which causes competition for resources and keeps population constant

• individual within population not idential but have variation

• variation help adapt better to environment increase survival rate (natural selection)

• properly adapt to environment causes again cycle of speciation

common ancestor

• A group of organisms is said to have common descent if they have a common ancestor.  all living organism come from common ancestor

James Hutton & Lyell

Suggest that geological process take time and is same process changed the world until today

Uniformitarianism: idea of Earth has always changed in uniform ways and present is key to the past

Darwin concept of evolution: by natural selection

Lamarck

Thought that acquired charactersitics are traits that are altered during life and then change would happen in one generation. he was correct only on the fact that , as species change in response to environemnt.

Mathius

identified probability, saw hunger, and disease caused by God in order to stop overpopulation. Inspired Darwin to refine natural selection by stating a reason for competition between animals.

Lamarck evolution by use of organs

change in envrionemnt led to use of certain organs and disuse of others

organs used to have greater use, now shrink

changed aqcuired pass down after 1 generation

Two ideas Darwin natural selection

natural selection is caused of adaptive evolution and it explains unity and diversity

Natural selection

mechanism by which evolution occurs

differential success in reproduction among individuals that vary heritable traits

reproductive differences emerge as each individual interacts with environment

can increase adaptation in an organism

adaptation

A change that allows an organism to function better in a particular environment.

• If an environment changes over time, or if individuals of a particular species move to a new environment, natural selection may result in adaptation of these new conditions, sometime given rise to new species.

artificial selection

identification by humans of desirable traits in plants and animals, and the steps taken to enhance those traits in future generations

Selective Breeding

form of artificial selection, where by man, intervenes in the breeding of species to produce desired traits in offsprings (rapid change)

• dog possesing desired traits are bred in hope that they will pass on alleles for certain traints desired.

Natural selection

• Over time, natural selection can increase the adaptation of organisms to their environment. 

Natural selection is more a process of editing than a creative mechanism. mechanism by which evolution occurs

• if environment change over time or species migrates, natural selection can result in adaptation of new conditions sometime give rise to new species.

Transgenic organism

Genetically modified has been altered through recombinant of DNA tech which involves either the combining of DNA from different genomes or the insertion of foreign DNA into a genome.\

gene- segment of DNA contain trait- transcribe translate to make protein

Soya Argentina today country relies on soya

adaptive radiation is consequence divergent evolution

surge of one species close to one ancestor which different than convergen evolution

analogous structures

biological strucutes havign similar function

caused by convergent evolution

Trisomy 21

Down Syndrome