Chapter 7 Classification & Biodiversity

Question 1

Define phylogenetic

Answer 1

Reflecting evolutionary relatedness

Question 2

What is a phylogenetic tree?

Answer 2

A diagram showing descent, with living organisms at the tips of the branches and ancestral species in the branches with branch points representing common ancestors. The length of the branches indicate the time between common ancestors.

Question 3

Define taxonomy

Answer 3

The identification and naming of organisms

Question 4

Define classification

Answer 4

Putting items into groups

Question 5

Define hierarchy

Answer 5

A system of ranking in which small groups are nested components of larger groups

Question 6

Define taxon

Answer 6

Any group within a system of classification

Question 7

Why is phylogenetic classification described as discrete and hierarchal?

Answer 7

Taxa are discrete meaning an organism belongs in one taxon and in no other.
Classification has bigger taxa containing smaller taxa, therefore hierarchal

Question 8

Why is a classification system needed?

Answer 8

Allows the inference of evolutionary relationships.
We can predict the characteristics of new animals that are discovered based on our general understanding of other similar animals.
Easier to communicate
Rate of extinction is easier to calculate by counting families rather than species.

Question 9

What are the 3 domains?

Answer 9

Eubacteria
Archaea
Eukaryota

Question 10

What are the 5 kingdoms?

Answer 10

Animalia 
Plantae
Fungi
Protictista
Prokaryota

Question 11

What are the characteristics of prokaryotes?

Answer 11

Unicellular, no nucleus, mesosmes in some, 70s ribosomes, no endoplasmic reticulum, no vacuoles, peptidoglycan Cell walls, saprophytic/parasitic or autotrophic, no nervous coordination.

Question 12

What are the characteristics of protoctista?

Answer 12

Eukaryotic, unicellular/multicellular, nucleus, mitochondria, chloroplasts in some, 80s ribosomes, endoplasmic reticulum, vacuole in some, cellulose cell walls in some, some autotrophic and some heterotrophic, no nervous coordination

Question 13

What are the characteristics of plants?

Answer 13

Eukaryotic, multicellular, nucleus, mitochondria, chloroplasts, 80s ribosomes, endoplasmic reticulum, large central permanent vacuoles, cellulose cell wall, autotrophic, no nervous coordination

Question 14

What are the characteristics of fungi?

Answer 14

Eukaryotic, unicellular/hyphae, nucleus, mitochondria, no chloroplasts, 80s ribosomes, endoplasmic reticulum,large central permanent vacuole, chitin Cell walls, saprophytic or parasitic, no nervous coordination

Question 15

What are the characteristics of animals?

Answer 15

Eukaryotic, multicellular, nucleus, mitochondria, no chloroplasts, 80s ribosomes, endoplasmic reticulum, small scattered temporary vacuoles, no cell wall, heterotrophic, nervous coordination.

Question 16

Define homologous structures

Answer 16

Structures in different species with a similar form and developmental origin, but different function.

Question 17

What is divergent evolution?

Answer 17

Where a common ancestral structure has evolved and performs different functions. This is supported by homologous structures.

Question 18

What is an example of a homologous structure?

Answer 18

The pentadactyl limb (having five digits). It’s basic structure is the same in all four classes (mammals, reptiles, birds, fish and amphibians). However, the limb has adapted for different functions.

Question 19

Define analogous structures.

Answer 19

Structures in different species that have a corresponding function, but have a different form and developmental origin.

Question 20

What is convergent evolution?

Answer 20

Structures evolve similar properties, but have different developmental origins.

Question 21

What are the 4 ways of assessing relatedness with genetic evidence?

Answer 21

DNA sequences
DNA hybridisation
Amino acid sequences
Immunology

Question 22

How do DNA sequences assess relatedness?

Answer 22

More closely related species show more similarity in their DNA base sequences than those more distantly related. DNA analysis has confirmed evolutionary relationships and corrected mistakes made in classification based on physical characteristics.

Question 23

How does DNA hybridisation assess relatedness?

Answer 23

DNA from two species are extracted, separated and cut into fragments. The fragments are mixed and where they have complementary base sequences, they hybridise together. The more closely related species have more hybridisations.

Question 24

How do amino acid sequences assess relatedness?

Answer 24

The degree of similarity in the amino acid sequence of the same protein in two species will reflect how closely related they are.

Question 25

How does immunology assess relatedness?

Answer 25

If you mix the antigens of one species with specific antibodies of another, the antigens and antibodies make a precipitate. The closer the evolutionary relationship, the more precipitate formed.

Question 26

Define species

Answer 26

A group of organisms that can interbreed to produce fertile offspring.

Question 27

What is the morphological definition of species?

Answer 27

If two organisms look very similar, they are likely to be in the same species. Sexual dimorphism (physical differences between males and females) must be taken into account.

Question 28

What is the reproductive definition of species?

Answer 28

Two organisms are in the same species if they can interbreed to produce fertile offspring.

Question 29

Define binomial system (also called binomial nomenclature)

Answer 29

The system of giving organism a unique name with two parts, the genus and species.

Question 30

What are the advantages of the binomial system?

Answer 30

Unambiguous naming. Based on Latin, can be used globally. Implies that two species sharing part of their name are closely related.

Question 31

How do you use the binomial system?

Answer 31

The genus is the first word and has a capital letter The species name comes second and does not have a capital letter The first time the genus name is used in a text it is written in full, but if used again, the genus name may be abbreviated Both names are printed in italics or underlined when hand-written

Question 32

Define biodiversity

Answer 32

The number of species and the number of individuals in each species in a specified region

Question 33

What are the three reasons biodiversity can increase or decrease?

Answer 33

Succession (time) Natural selection Human influence

Question 34

What is the equation for the simpsons index?

Answer 34

1-[n(n-1)/[N(N-1) n=individuals in each species N= total amount of species

Question 35

Define polymorphism

Answer 35

The occurrence of more than one phenotype in a population that cannot be accounted for by mutation alone.

Question 36

How can number of alleles assess biodiversity?

Answer 36

A genes position on a chromosome is its locus. A locus can show polymorphism if it has two or more alleles at frequencies greater than would occur by mutation alone. If a gene has more alleles it is more polymorphic, therefore more biodiversity as more phenotypes are possible. For example, if gene T has two alleles, but gene S has 31 alleles, gene S has a greater biodiversity.

Question 37

How can the proportion of alleles assess biodiversity?

Answer 37

If we consider the whole gene pool, if there is a greater variation of alleles present in a population, the greater the biodiversity in relation to the characteristic associated with that gene.

Question 38

How does DNA fingerprinting assess biodiversity?

Answer 38

Comparing the number and position of bands in the DNA profiles of a population. More differences indicate a greater biodiversity.

Question 39

What is natural selection?

Answer 39

The gradual process in which inherited characteristics become more or less common in a population, in response to the environment determining the breeding success of individuals possessing those characteristics.

Question 40

What are the three types of adaptive traits that can occur as a result of natural selection?

Answer 40

Anatomical Physiological Behavioural