A3 .1 & A3.2 flashcards

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Define Organism

An individual plant, animal, bacterium or any other living thing.

Define Variation

Any difference between the individuals in a species or group of organisms of any species.

State the importance of Variation

Variation is essential for the future of life because evolution by natural selection could not happen without it.

Define species according to the morphological species concept.

Group of individuals that are morphological similar to one another and are morphological distinct from other such groups.

What is name of the scientist who pioneers the species research

Carl Linnaeus

Define species according to the biological species concept.

A group of organisms that can successfully interbreed and produce fertile offspring.

Describe limitations of the biological species concept, with mention of hybrids and geographical separation. ​

The biological species concept is difficult to apply due to geographical separation and gradual divergence. In addition to species resulting from hybridization are not distinct.

Define population

A group of individuals of the same species living in the same are and time.

Define speciation

The natural process where species diverge to form a new species

Explain the difficulties in distinguishing between populations and species during speciation.

Mutations within the gene pool can cause the population to be more genetically diverse, eventually causing them to become different species. The gradual process is why it is difficult to determine when speciation occurs.

Outline why the chromosome number is important?

Chromosome number is a fundamental characteristic of any species.

Explain why the typical number of chromosomes in a diploid cell is an even number.

Diploid cells are formed when two haploid cells containing one set of each type of chromosome fuse together. Which results in the diploid having two sets of each type of chromosome resulting in an even number of chromosome.

State the number of chromosomes in humans and in chimpanzees.

Humans have 46, while Chimpanzees have 48.

State that point of the actual number of chromosomes.

The actual number is not very significant, but it is important when verifying that each member of a species has the same number.

Define karyotype and karyogram.

The characteristic types of the chromosomes in a species. ;; The image showing the karyotype

List the characteristics by which chromosomes are paired and arranged on the karyogram.

They are organized by size and structure, starting with the largest pair, with the location of the centromere and the pattern of banding being distinguishable features between similar sized chromosomes.

Distinguish between testable hypotheses and non-testable statements.

Testable hypotheses are statements that can can be scientifically testes and evaluated through experiments and evidence. While non-testable statements are subjective claims that lack empirical evidence and cannot be scientifically examined or verified.

Define genome

All the genetic information of one individual organisms or group of organisms.

Define gene

A length of DNA carrying a specific sequence — can be hundreds or thousands of nucleotides long.

Define allele

One or more alternative form of genes, made through mutation.

Outline the cause and effect of “single-nucleotide polymorphisms” in genomes.

Positions in a gene where more than one base may be present. With 100 million different SNP in human genomes with over 3 billion base pairs.

Explain the variation in genome sizes

Genome size is measured in base pairs. Genomes can consist of coding and non-coding regions.

Explain the variation in base sequences

Two populations will have differences in their base sequence, and overtime, the differences can accumulate. Some genes have a vital function, and so changes to the base sequence are less common. Different species have different number and types of genes.

Describe reasons why a larger genome does not necessarily indicate presence of more genes.

Some organisms have large genomes but contain a lot of non-functional DNA, and do not necessarily contain more functioning genes. With about half of human DNA are composed of transposons or ‘junk DNA’ that have no known function.

State the units for measuring genome size.

Base pairs (bp) or kilobase pairs (kb) for smaller genomes, and megabase pairs (Mb) or gigabase pairs (Gb) for larger genomes.

Define whole genome sequencing

Whole genome sequencing is determining the entire base sequence of an organism’s DNA.

State that technological improvements have sped the DNA sequencing process.

With technological improvements, it was possible to form sequencing a human genome to cost $100 million in 2001 to low as $1000 in 2020.

List applications of genome sequencing.

• Disease diagnosis

• Genetic counselling

• Cancer research and treatment

• Pharmaco genomics

• Forensic and genetic genealogy

• Agricultural and livestock breeding

• Evolutionary biology

• Microbial sequencing

• Genetic engineering

• Bioinformatics

Compare sexual and asexual reproduction.

In sexual reproduction, inter breeding allows the mixing of trials each generation, and actually prevents significant differences between individuals. Many species can reproduce asexually and sexually. As long as there is some sexual reproduction, they remain as a unified group.

Discuss difficulties in applying the biological species concept to asexually reproducing species.

If these clones don’t interbreed, then they are a separate species according to the biological species concept. Hundreds of different clones have been identified, and named as a separate species.

Define Vertical gene transfer

The passing of genes from parent to offspring

Define Horizontal gene transfer

Genes that are transferred from one species to another.

Explain how sexual reproduction maintains chromosome number within a species.

Meiosis is the process through which sexually reproducing organisms maintain their particular chromosomal numbers from generation to generation. Meiosis generates sperm and eggs.

Outline cross-breeding between closely related species producing sterile offspring because of differences in parent chromosome numbers. ​

If parents are of differing chromosome pair numbers, the offspring will have an odd number of chromosomes, which leaves them unable to produce chromosomally balanced gametes.

What is F.

White Oak

Define DNA barcode

DNA barcodes are short sections of DNA which are distinctive enough to identify a species.

Define environmental DNA

Environmental DNA can be used for species identification.

Outline the use of “DNA barcoding” to identify species from environmental DNA.

It allows the identification of species from small pieces of tissues found in the environment, that would otherwise be difficult to recognize. Samples can be collected from water, solid and other abiotic parts of the environment to obtain environmental DNA — this can be used for species identification.

List applications of DNA barcoding using environmental DNA.

rapid investigation of the biodiversity of habitats.

​Define “taxonomy”

The branch of biology called taxonomy focuses on the classification of living things.

Outline the benefits of having a system of classification of organisms. ​

Communication of biology info between scientists. Predictions of characteristics, if characteristics of a taxonomic group are known, then information about individual species in the group is also known. Species in the same group probably share a common ancestor, indicating information about how species evolved.

List the levels of classification in the traditional hierarchy of taxa.

Kingdom, phylum, class, order, family, genus and species.

Discuss limitations of the traditional classification system.

Because the system is based on human judgement, it doesn't easily accommodate discoveries, such as species or changes due to disagreement and changes.

Define “synapomorphies.”

If organisms in the same taxonomic group evolved from a common ancestor, then they should share traits inherited by said common ancestor.

Define clade.

A group of organisms evolved from a common ancestor. Including living species as well as the ancestral species and extinct species that also evolved from the common ancestor.

List evidence used for placing organisms in a clade.​

It can be difficult to determine clade, therefore base sequences of gene and amino acid sequence of protein are used. When sequence data is not available, morphological traits may be used.

Identify a clade as a branch in a cladogram.

Every species is part of multiple clades; smaller clades are nested in larger ones

Outline the use of a “molecular clock” to determine time since divergence between two clades.​

The molecular clock can only give estimates, since it is based on the assumption that mutation rates are constant.

State that DNA and amino acids sequences can be the basis for constructing cladograms. .

There will be fewer difference in base or amino acid sequence. Conversely, species that diverged a longer time ago are likely to have more differences. By comparing base sequences, it is possible to estimate how long ago pairs of species diverged.

Define “parsimony” as used in a biological context

Parsimony refers to the concept of parsimony or simplicity in constructing phylogenetic trees.

Outline how the principle of parsimony relates to evolutionary divergence between the members of a clade.​

The principle of parsimony in the context of evolutionary divergence within a clade involves favoring the explanation requiring the fewest evolutionary changes or events to explain the observed diversity.

Define “cladogram”.

A cladogram is a diagram representing evolutionary relationships between organisms based on shared characteristics.

Define node

A node represent the point at which ancestral species split to form two or more clades.

Analyze a cladogram to deduce evolutionary relationships, common ancestry and clades.

Even thought they’re strong evidence. Cladograms are constructed on the assumption that the smallest possible number of mutations that can account for current base or amino acid sequence differences.

Explain why the development of cladistics lead to the reclassification of some species.

Cladistics research confirmed that the traditional classification matches the most probable pathways of evolution.

Outline the reason and evidence for the reclassification of the figwort family.

It was found that species in the figwort family did not share a single common ancestor so were not a true clad, which led to a major reclassification.

Define convergent evolution

The process where by distantly related organisms independently evolve similar traits to adapt to similar necessities.

List the three domains of life.

Eubacteria, Archaea and Eukaryota.

Discuss evidence from rRNA base sequences that led to the reclassification of life from two cell types (prokaryotic and eukaryotic) to three domains.

Prokaryotes are diversed. In particular, when the base sequence of robosomal RNA were determined, it became apparent that there are two distinct groups of prokaryotes.

Interpret the tree diagram that illustrates the evolutionary relationship between organisms of the three domains.

The tree diagram is split between the 3 domains. The tree is essentially a cluster of clads that show the cladogram of the origins & similarities among the 3 domains.

define Root

A root is the base of the cladogram, represents the hypothetical common ancestor of all the clades.

Define terminal Branch

The terminal branch are ends that represent individual clads. These may be species or groups of species that not subdivided on the cladogram.