A3: Diversity of Organisms

Question 1

Variation

Answer 1

Variation refers to differences between members of a group. Variation can be discrete or continuous.

Question 2

Discrete Variation

Answer 2

Traits that can be put into distinct qualitative categories.

e.g. blood type

Question 3

Continuous Variation

Answer 3

Traits that vary along a quantitative continuum. Most types of biological variation are continuous.

e.g. Height

Question 4

Intraspecies variation

Answer 4

Variation within a species - is inheritable

Question 5

Interspecies variation

Answer 5

Variation between species

Question 6

Biological Species Concept

Answer 6

A species is a group of actually or potentially interbreeding populations which are reproductively isolated from other such groups.

Looks at a combination of Morphology, habitat, and allele.

Championed by ornithologist Ernst Mayr (1942)

Question 7

Binomial Nomenclature Benefits

Answer 7

• Reflects evolutionary relationship between organisms
• Enables scientists to talk to each other in the same language

Question 8

Speciation

Answer 8

the formation of new and distinct species in the course of evolution.

Question 9

Diploid Cells

Answer 9

Cells that have an even number of chromosomes (one of each parent)

Question 10

Haploid gametes

Answer 10

cells for sexual reproduction have half the chromosome or one set of chromosomes.

Question 11

Karyogram

Answer 11

Diagram or photograph of the chromosomes present in a nucleus arranged i homologous pairs of decreasing length.

Question 12

Telomere DNA

Answer 12

DNA at the end of chromosomes that does not code for proteins.

Question 13

Genome Wide Association Studies (GWAS)

Answer 13

a research approach used to identify genomic variants that are statistically associated with a risk for a disease or a particular trait.

Question 14

Single Nucleotide Polumorphism

Question 15

Asexual reproduction

Answer 15

Asexual reproduction occurs when a single parent passes on its full set of genes to offspring, resulting in genetically identical offspring.

Asexually reproducing organisms are classified into species based on appearance or biochemical similarities.

Question 16

Horizontal Gene Transfer

Answer 16

The movement of DNA between individuals through mechanisms that are not the normal movement of DNA from parent to offspring.

E.g. bacteriophage

Horizontal gene transfer is frequent among bacteria. Horizontal gene transfer can occur in eukaryotes, however it appears to be less frequent.

Question 17

Apomixis

Answer 17

Scientific name for cloning.

A huge number of genetically unique clones can be formed via apomixis, resulting in populations of related, but genetically isolated clones. Since there is no interbreeding between populations, each population is considered a separate species according to the Biological Species Concept

Question 18

Chromosome number as a species trait

Answer 18

Species tend to be able to mate if they have the same number of chromosomes.

E.g. Horses have 64 chromosomes while donkeys have 62 - Mules have 63 and can not reproduces as they can not be a homologous pair.

Question 19

Dichotomous Key

Answer 19

Tool used to identify a species based on observable traits.

If statement A is true go to step 3 e.g.

Question 20

Taxonomy

Answer 20

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

Question 21

Benefits of Taxonomy

Answer 21

1. Communication of biological information between scientists
2. Predictions of characteristicsts
3. Species in the same group probably share a common ancestor, indicating information about how species evolved.

Question 22

Characteristics that determine cladograms

Answer 22

• Morphological homologies
• Developmental patterns
• Fossil records
• Genetically determined behavioral traits
• Molecular homologies

Question 23

Homologous

Answer 23

shared characteristics due to common ancestry (divergent evolution)

Question 24

Analogous

Answer 24

shared characteristics not due to common ancestry (convergent evolution)

Question 25

Genus

Answer 25

a group of similar and closely related species

Question 26

Morphological species concept

Answer 26

Species are groups of organisms with shared traits e.g. shape, color, and other distincitive features

Question 27

Benefits of morphological species concept

Answer 27

• can be applied to asexual organisms
• does not require any information on the extent of gene flow
• can be applied to extinct and fossilized species
• Easiest and fastest concept to apply in the field because it is based only on the appearance of the organism

Question 28

Disadvantages of morphological species concept

Answer 28

• Relies on subjective criteria and researches may disagree on which structural features distinguish a species
• Different individuals in a species may appear very different, such as males and females

Question 29

Centromere

Answer 29

Constriction of the chromosome

Question 30

Homozygous

Answer 30

Having two identical alleles of a gene

Question 31

Heterozygous

Answer 31

Having two different alleles of a gene

Question 32

Karyotype

Answer 32

The number and type of chromosomes present in an organism

Question 33

Three processes of genetic transfer/horizontal gene transfer in prokaryotes

Answer 33

Transformation
Transduction
Conjugation

Question 34

Transformation (Gene transfer)

Answer 34

The alternation of a bacterial cell’s genotype by the uptake of naked DNA.

Question 35

Transduction (Gene transfer)

Answer 35

Occurs when a bacteriophage infects a bacterial cell and then transfers some of the cell’s DNA to another bacterium. An error in the phage lytic cycle.

Question 36

Conjugation (Gene transfer)

Answer 36

Involves a direct physical interaction between two bacterial cells and transfer of genetic material from a donor bacterium to a recipient bacterium.

Question 37

Kingdom

Answer 37

The largest and most inclusive group

Question 38

Phylum

Answer 38

organisms constructed on a similar plan

Question 39

Domain

Answer 39

Highest taxonomic rank - archaea, eubacteria, and eukarya.

Question 40

Genus

Answer 40

A group of similar and closely related species

Question 41

Species

Answer 41

A group of organisms capable of interbreeding to produce fertile offspring.