LECTURE 06: SPECIATION AND SYSTEMATICS

Question 1

Speciation

Answer 1

the process by which new species arise

Question 2

systematic

Answer 2

the study of the diversity of organisms and their evolutionary relationships

Question 3

speciation

Answer 3

the process by which populations evolve to become distinct species. this often involves the development of reproductive barriers that prevent gene flow between populations.

Question 4

biological species concept

Answer 4

defines a species as a group of individuals that can interbreed and produce fertile offspring in natural conditions. according to this concept, different species are reproductively isolated from one another.

Question 5

reproductive barriers

Answer 5

biological factors that prevent different species from interbreeding. they maintain the separation of species and can be prezygotic (before fertilization) or postzygotic (after fertilization).

Question 6

Behavioural isolation

Answer 6

differences in mating behaviours or rituals that prevent individuals from different species from recognizing each other as potential mates. for example, different bird species may have unique songs that attract only their own kind.

Question 7

temporal isolation

Answer 7

occurs when species breed at different times (day, season, or year), preventing interbreeding. for example, 2 plant species may release pollen at different times of the year.

Question 8

mechanical isolation

Answer 8

physical differences in reproductive structures that make mating impossible between species. for example, certain insects have specialized genital structures that do not fit with those of other species.

Question 9

gametic isolation

Answer 9

even if individuals from different species do mate, their gametes (sperm and egg) may not be compatible, preventing fertilization.

Question 10

hybrid inviability

Answer 10

hybrids (offspring of individuals from different species) may be produced, but they do not develop properly and often die early in their life cycle

Question 11

hybrid infertility

Answer 11

hybrids may be healthy and survive to adulthood, but they are sterile and cannot produce offspring (eg. mules, which are hybrids of horses and donkeys).

Question 12

allopatric speciation

Answer 12

speciation that occurs when populations of a species are geographically separated, leading to the evolution of reproductive barriers. over time, genetic differences accumulate due to natural selection, mutation, and genetic drift, resulting in the formation of new species.

Question 13

reproductive incompatibility

Answer 13

a condition in which members of different populations of species are geographically separated, leading to the evolution of reproductive barriers. over time, genetic differences accumulate due to natural selection, mutation, and genetic drift, resulting in the formation of new species

Question 14

reproductive incompatibility

Answer 14

a condition in which members of different populations or species cannot mate successfully due to genetic, behavioural, or physical differences.

Question 15

sympatric speciation

Answer 15

speciation that occurs without geographical isolation. it often involves changes in behaviour, ecological niche differentiation, or genetic factors like polyploidy.

Question 16

polyploidy

Answer 16

a condition a which an organism has more than 2 complete sets of chromosomes. it is common in plants and can lead to the formation of new species

Question 17

autopolyploid

Answer 17

an individual with multiple sets of chromosomes derived from a single species.

Question 18

allopolyploid

Answer 18

an individual with multiple sets of chromosomes derived from different species. hybridization between 2 species followed by chromosome doubling can result in an allopolyploid.

Question 19

adaptive radiation

Answer 19

a process in which a single ancestral species rapidly diversifies into a variety of new species that occupy different ecological niches. this often happens when organisms colonize new environments with diverse habitats.

Question 20

adaptive radiation

Answer 20

a process in which a single ancestral species rapidly diversifies into a variety of new species that occupy different ecological niches. this often happens when organisms colonize new environments with diverse habitats.

Question 21

systematics

Answer 21

the scientific study of the diversity of organisms and their evolutionary relationships. it involves classifying organisms and constructing phylogenetic trees to show how species are related.

Question 22

Taxon (plural: taxa)

Answer 22

a group of one or more populations of organisms classified together. A taxon can represent any rank in the biological classification systems, such as species, genus, family, etc.

Question 23

Taxonomic categories

Answer 23

the hierarchy of classification in biological taxonomy, which includes, from broadest to most specific: domain, kingdom, phylum, class, order, family, genus, and species.

Question 24

monophyletic group (clade)

Answer 24

A group that consists of an ancestral species and all its descendants. it represents a single branch on the tree of life.

Question 25

paraphyletic group

Answer 25

a group that includes an ancestral species and some but not all, of its descendants. this grouping does not accurately represent evolutionary relationships because it leaves out some descendants.

Question 26

polyphyletic group

Answer 26

a group that contains species with different ancestors. it does not include the most recent common ancestor of all members, making it an unnatural grouping.

Question 27

phylogenetic tree

Answer 27

a branching diagram that represents the evolutionary history of a group of organisms, It shows the relationships among various species based on their genetic, morphological, or behavioural characteristics.