Theme A: A4 Ecosystems - A4.1 Evolution and Speciation

Question 1

evolution

Answer 1

the process of CULMATIVE change in the HERITABLE characteristics of a POPULATION.

Question 2

modern synthesis theory (neo-Darwinism)

Answer 2

The modern synthesis theory combines Darwin’s theory of evolution by natural selection with Mendell’s work about genetics.

Question 3

Lamarckism (Lamarckian evolution)

Answer 3

organisms acquired characteristics through time and then passed them onto their offspring.

Question 4

selective breeding

Answer 4

breeders choose the males and females with most agriculturally desirable genetic characteristics and breed them together.

Question 5

artificial selection

Answer 5

farmers and breeder choose which animals will reproduce together and which will not.

Question 6

homologous structures

Answer 6

structures derived from the same body part of a common ancestor (e.g. five-fingered limbs in humans, bats, and whales)

Question 7

pentadactyl limbs

Answer 7

“penta” meaning five, and “dactyl” meaning fingers. the shape and number of bones may vary and the specific function may be very different, but the general format is the same.

Question 8

analogous structures

Answer 8

structures that may have the same function but don’t necessarily come from the same body part and do not indicate a common ancestor.

Question 9

phylogeny

Answer 9

The evolutionary history and relationships among species or groups of organisms, typically represented as a phylogenetic tree, which illustrates common ancestry and divergence.

Question 10

convergent evolution

Answer 10

The process by which unrelated or distantly related organisms independently evolve similar traits or adaptations in response to similar environmental pressures or ecological niches. Examples include the wings of bats, birds, and insects.

Question 11

divergent evolution

Answer 11

The process by which two or more related species become increasingly different from their common ancestor, often due to adapting to different environmental pressures or ecological niches.

Question 12

marsupial

Answer 12

A subclass of mammals (Marsupialia) characterized by giving birth to relatively undeveloped offspring, which then typically continue to develop inside a pouch (marsupium) on the mother’s body.

Question 13

natural selection

Answer 13

A process in which individuals with advantageous heritable traits are more likely to survive, reproduce, and pass on these traits to offspring, leading to changes in the traits of a population over generations.

Question 14

reproductive isolation

Answer 14

in some situations, member of the same species can be prevented from reproducing because there is an insurmountable barrier between them. Can be geographical, temporal, or behavioural barrier.

Question 15

geographical isolation

Answer 15

happens when physical barriers like land or water formations, prevent males and females from different parts of a population form finding each other, thus making interbreeding impossible.

example: a river mountain, a clearing in a forest. man made barriers also exist like roads, dams, the great wall of china, etc. a more specific example is the Congo River which acts as a physical barrier that prevent s2 populations of primates from interacting/interbreeding. the primates to the north and east of the river are chimpanzees and the bonobos are to the south. differences in food, enemies, habitat have lead to differences in traits, notably behavioural traits.

Question 16

differential selection

Answer 16

when one environment favours certain traits and another environment favours different traits, there is differential selection.

Question 17

allopatric speciation

Answer 17

when a new species forms from an existing species because the population is separated by a physical barrier, Geographical isolation leads to allopatric speciation.

Question 18

sympatric speciation

Answer 18

when a new species forms from an existing species living in the same geographical area. In this case, speciation can be caused by temporal or behavioural isolation.

Question 19

temporal speciation

Answer 19

refers to incompatible time frames that prevent populations or gametes from encountering each other. (e.g. if one population of mammals is hibernating or has not returned from migration when another population of the same species is ready to mate, this would form a temporal barrier between the two gene pools. OR if female parts if flowers from one population reach maturity earlier or later than the release of pollen from another population, the 2 will find it difficult to produce offspring.)

Question 20

behavioural isolation

Answer 20

when part of the population develops a different behaviour that isolates it from the rest of the population. it can happen when one population’s lifestyle is not compatible with those of another population. (e.g. if part of a population of songbirds gradually develops a different song to attract mates, then over time that part will only mate with those that recognise its song. another example considers courtship behaviour).

Question 21

adaptive radiation

Answer 21

when many similar but distinct species evolve relatively rapidly from a single species or from a small number of species. This happens because variation within a population allows certain members of that population to occupy different niches.

Question 22

niche

Answer 22

a position or role within a community.

Question 23

locus

Answer 23

a genes positon in a chromosome.

Question 24

courtship behaviour

Answer 24

A set of display actions or rituals performed by animals to attract a mate, which often ensures species recognition, assesses mate quality, and increases the likelihood of successful reproduction.

Question 25

polyploidy

Answer 25

when a cell contains 3 or more sets of chromosomes.