Unit 3 - Topic 1 (Classification Processes)

Question 1

What is classification?

Answer 1

Classification is the systematic and rational grouping of both organisms and ecosystems in such a manner that it shows the biological relationships between them

Question 2

What is biological classification based on?

Answer 2

• physical features (Linnaen system)
• reproductive methods
• molecular sequences (cladistics)

Question 3

What are the 6 kingdoms?

Answer 3

• bacteria
• archaea
• protista
• fungi
• plantae
• animalia

Question 4

What is the hierarchical classification (8)?

Answer 4

Called the Linnaean System:
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species

Question 5

What is classification by mode of reproduction?

Answer 5

Organisms can also be classified according to the mode of reproduction. For example: Sexual (genetically blended offspring) vs asexual (identical offspring)

Question 6

What is r-selection?

Answer 6

R-selected species have a high growth rate but low survivability (“cheap” offspring)

Question 7

What is k-selection?

Answer 7

K-selected species have a low growth rate but high survivability (“expensive” offspring)

Question 8

What is classification by molecular sequences?

Answer 8

• DNA sequences
• protein sequences

Question 9

Why do we need multiple definitions of a species?

Answer 9

Multiple definitions of species are required because some species definitions/concepts cannot be applied to organisms that do not reproduce sexually

Question 10

What are the two ways to define a species?

Answer 10

• biological species
• phylogenetic species

Question 11

What is a biological species?

Answer 11

A biological species is any two organisms that can reproduce to make fertile offspring

Question 12

What is a phylogenetic species?

Answer 12

A phylogenetic species is the smallest group of organisms that share a common ancestor and can be distinguished by a unique set of morphological and or genetic traits

Question 13

What are interspecific hybrids?

Answer 13

Crossing of two species that are from within the same genus

Question 14

What is stratified sampling?

Answer 14

Stratified sampling is when a population is divided into smaller groups (strata) based on shared characteristics, and then samples are taken from each group to make sure all groups are represented.

Question 15

What is the purpose of stratified sampling?

Answer 15

The purpose of stratified sampling is to estimate population size, density, and distribution, as well as to study environmental gradients, profiles, zonation, and stratification

Question 16

How are sites chosen in stratified sampling?

Answer 16

By dividing into strata/zones

Question 17

Which method are used in stratified sampling?

Answer 17

Transects and quadrats

Question 18

How to minimise bias in stratified sampling?

Answer 18

Bias in stratified sampling is minimised by:
- using an appropriate sample size and number
- random-number generators
- clear counting criteria
- and by calibrating equipment and noting associated precision

Question 19

What is cladistics?

Answer 19

Cladistics is an approach to biological classification in which organisms are categorised into groups based on evolutionary lines of descent

Question 20

What are evolutionary line of descent?

Answer 20

Evolutionary lines of descent are determined by physical characteristics and molecular sequencing (DNA or proteins)

Question 21

What is molecular sequencing?

Answer 21

Molecular sequencing is the process of determining the exact order of the building blocks (nucleotides, or amino acids) in a molecule

Question 22

What is a cladogram?

Answer 22

• cladograms are branching diagrams used to represent the evolutionary relationships between a number of species.
• similar to phylogenetic trees but do not show the degree of genetic change or time passed

Question 23

What is a clade?

Answer 23

A clade is a group consisting of all the
descendants of a particular ancestor organism

Question 24

What are assumptions of cladistics? (3)

Answer 24

• change in characteristics occurs in lineages over time
• any group of organisms is related by descent from a common ancestor.
• there is a bifurcation, or branching, pattern of lineage splitting.

Question 25

What is carrying capacity?

Answer 25

The size of the population that can be supported indefinitely on the available resources and services of that ecosystem

Question 26

What is exponential population growth? (3)

Answer 26

- if the birth rate of a population remains consistently higher than the death rate, the population may grow exponentially - exponential growth pattern has a 'J-curve' - if favourable conditions continue a population explosion can occur

Question 27

What is logistic population growth? (3)

Answer 27

- when a population reaches equilibrium (stable, constant) the species reaches its maximum population size that the ecosystem can sustain (known as the carrying capacity). - this pattern of growth is known as logistic growth and represented by a 's-shape curve'

Question 28

What is a keystone species?

Answer 28

A species that plays a critical role in maintaining the structure and functioning of their ecosystem

Question 29

What is taxonomy?

Answer 29

Taxonomy is the scientific study of classifying, naming, and organizing organisms based on their characteristics and relationships.

Question 30

What is binomial nomenclature?

Answer 30

Binomial nomenclature is the system of giving each species a two-part scientific name: the genus name followed by the species name.

Question 31

What is the biological species concept?

Answer 31

The biological species concept defines a species as a group of organisms that can interbreed and produce fertile offspring.

Question 32

What is morphological species concept?

Answer 32

The morphological species concept defines a species based on its observable physical traits and structural features.

Question 33

What is the phylogenetic species concept?

Answer 33

The phylogenetic species concept defines a species as a group of organisms that share a common evolutionary history and ancestry.

Question 34

What is bifurcation?

Answer 34

Bifurcation is the splitting of a lineage or evolutionary line into two distinct branches, often seen in phylogenetic trees.

Question 35

What are eutherians?

Answer 35

Eutherians are mammals that give birth to live young and nourish them via a placenta - example: human

Question 36

What are monotremes?

Answer 36

Monotremes are mammals that lay eggs instead of giving birth to live young - example: platypus

Question 37

What are marsupials?

Answer 37

Marsupials are mammals that give birth to underdeveloped young, which continue to grow and develop inside a pouch - example: kangaroo

Question 38

What is protein conservation?

Answer 38

Protein conservation refers to the preservation of protein sequences across different species, indicating evolutionary relationships and functional importance.

Question 39

What is dating divergence?

Answer 39

Dating divergence is the process of estimating when two species split from a common ancestor during evolution.

Question 40

What is molecular phylogeny?

Answer 40

Molecular phylogeny is the study of evolutionary relationships among species using molecular data, such as DNA or protein sequences.

Question 41

What is plesiomorphic?

Answer 41

Plesiomorphic refers to an ancestral or primitive trait that is shared by multiple species.

Question 42

What is apomorphic?

Answer 42

Apomorphic refers to a derived or new trait that is unique to a particular species or group, distinguishing it from its ancestors.