unit 2 - evolution

what is allopatric speciation?

when species are separated by a geographic barrier, so they’re geographically isolated from each other

what is sympatric speciation?

• species become reproductively isolated without any geographic barrier

what is convergent evolution?

• when species become similar in phenotype

what is divergent evolution?

• when species become increasingly different

• adaptive radiation

what is adaptive radiaiton?

it’s essentially just divergent evolution but on a larger scale, so new species are being quickly reproduced

what is coevolution?

it’s when both species affect how each other evolves

what are the mechanisms of natural selection?

• stabilizing selection

• directional selection

• disruptive selection

explain stabilizing selection

intermediate/average traits are more favoured

explain directional selection

one extreme trait of species is favoured

explain disruptive selection

when both extreme traits of species is favoured

what is artificial selection?

• it’s similar to selective pressure

• instead of environment selecting for traits in species, it’s humans selecting for the traits

• for ex. humans want more source of meat, so they want more cows and chickens to breed to create bigger chicken/cow population

• another ex. when gardener’s breed for certain plants for their traits. for ex. gardeners bred more roses bc of their scent. overall this process leads to a decreased genetic diversity in plants.

• cows for more milk production as well

• better economy

• selective breeding

list out the evidences of evolution

• evidence from embryology

• evidence of fossil records

• evidence from DNA

• evidence from anatomy

• evidence from biogeography

explain evidence from DNA

• when species share similar DNA, essentially that means they look genetically similar

• result in similar phenotype

explain evidence of biogeography

• the more closer species are, the more related they are

explain evidence from embryology

• species with very similar embryo stages (stages before birth) indicates they could have common ancestor

explain evidence of anatomy

• species with similar structural elements means they could have common ancestor

• humans, bats and cats have similar arm bone structure

• vestigial structures

• homologous structures

explain homologous structures

• it’s when the structures between species are very similar

explain vestigal structures

• it’s when species have a structural element that has no function

• ex. in humans would be wisdom teeth

• ex. in penguins would be their “wings"

explain evidence from fossil records

• fossils = remains of animals

• diff. layers

• the younger layers = more similar to the actual organism still existing

• the older layers = look more different to the organism existing today

what is co-dominance?

• it’s when both traits/alleles of an organism is fully expressed

what’s incomplete dominance?

• it’s the mixing of 2 traits to show up as one

• for example when blue flowers and red flowers breed, they become purple flowers

explain monohybrid crossing

• doing punnet squares for one trait

• finding the likelihood for one trait

• genotype and phenotypes ratios + percentage

explain dihybrid crossing

• doing punnet squares for 2 traits

• finding the likelihood for 2 traits

• genotype and phenotype ratios + percentage

what are the mechanisms of microevolution?

• mutations

• gene flow

• gene drift

• sexual selection

• natural selection

• non-random mating

explain morphological species concept

• defines species based off their physical features (ex. body shape, body size, etc.)

explain biological species concept

• defines species by determining if 2 species can interbreed and have fertile offspring

fertile vs. infertile/sterile?

fertile:

• has the ability to produce offspring

infertile/sterile:

• can’t produce offspring

• can’t produce sperm/egg (ovum) cell

explain phylogenetic species concept

• defines organisms based off their evolutionary relationship

how did the 1st eukaryotic cell evolve?

• membrane in-folding

• endosymbiosis

explain process of membrane in-folding

• it’s when the membrane of prokaryotes fold inside the cell itself

• it creates structures such as the nuclear membrane, endoplasmic reticulum, etc.

explain process of endosymbiosis

• it’s when energy producing bacteria is engulfed by a larger cell

• the engulfment results in new structures such as chloroplasts and mitochondria

• host cell & endosymbiont

what is an endosymbiont?

• it’s the cell that becomes engulfed during endosymbiosis

• that engulfed cell is an energy-producing bacteria

what is a host cell?

it’s the large cell that engulfs the energy producing bacteria

what’s the term for sexual reproduction?

• conjugation

what’s the term for asexual conjugation?

• binary fission

explain of conjugation

• donor cell and recipient cell

• pilli of donor cell attaches to receptor sites on recipient cell

• an enzyme cuts a piece of plasmid in the donor cell and transfer this genetic material to recipient cell

• after the transferring of genetic information, the pilli of the donor detaches from the recipient cell

• finally in the end, there will be 2 cells with identical DNA

explain binary fission

• plasmid and DNA exists within a cell

• DNA and plasmid get duplicated

• one part of the DNA and plasmid move to one end of the cell and the other part of the DNA and plasmid move to the opposite end in the cell

• cytoplasm will be divided to create 2 identical cells with same DNA

what are membrane-bound organelles?

• they only exist in animal/plant cells

• ex. include: chloroplasts,nuclear membrane, endoplasmic reticulum, mitochondria

what type of cell does not contain membrane-bound organelles?

• bacterial cell since their too small and simple meaning they don’t need complex structures to help them function compared to a bigger cell like animal/plant cells

what are the 2 virus cycles?

• lytic cycle

• lysogenic cycle

explain the lytic cycle

• virus attaches to cell

• viral DNA enters the cell

• viral DNA destroys cell’s DNA and is now forced to replicate viral DNA only

• eventually, when there’s a build up of too many viruses, cell will break open and travel to other cells in the body

• disadvantage: dangerous process since virus can spread quickly to other cells

• advantage: body will feel the symptoms quicker, meaning that you can treat it sooner before it becomes worse

explain the lysogenic cycle

• virus attaches to cell

• viral DNA enters the cell

• viral DNA mixes with cell’s DNA

• replication of viral DNA + cell’s DNA occurs

• cell doesn’t break immediately and can only break open if some trigger happens (heat, chemical, etc.)

• in the meantime, the mixed viral DNA + cell’s DNA keeps replicating

• disadvantage: you won’t even know the virus exists since it doesn’t even break down and it could take up to years until you finally feel the symptoms but by then, it’s probably worse

explain what dormant/sleep-like state means in lysogenic cycle

• it means that us humans would’nt feel any infection since the cell doesn’t breakdown until it’s been a long time

what are the pre-zygotic mechanisms of macroevolution

• temporal isolation

• behavioural isolation

• mechanical isolation

• habitat isolation

• gametic isolation

explain temporal isolation

• it’s when certain organisms are only available during different times of the year/day

• for ex. some flowers could be available during sunrise and others can be available during sunset

explain behavioural isolation

• it’s when there 2 populations and they don’t response to each other’s behavioural actions (mating rituals)

• they only respond to the species in their own population

explain mechanical isolation

• it’s when the genital of species are incompatible

• for ex. an orchid only has a certain kind of shape to allow certain types of beetles to collect pollen/nectar from it

explain gametic isolation

• it’s when sperm and egg (ovum) is released from the species but they don’t fuse together to become a zygote

• for ex. fish and clam live in same environment and they both shed eggs and sperms but they don’t fuse together to become zygote

explain habitat isolation

• it’s when species live in different locations within the same ecosystem

what are the post-zygotic mechanisms of macroevolution?

• hybrid inviability

• hybrid breakdown

• hybrid sterility

what’s hybrid sterility

• it’s when an hybrid organism is sterile (can’t reproduce)

what’s hybrid inviability

it’s when the hybrid embryo dies in its embryo stage before even existing

what’s hybrid breakdown

it’s when hybrid species mate but their offspring are sterile/weak

what are the domains

• archea

• eubacteria

• eukarya

describe eukarya domain

• eurkaryotic (multicellular)

• contains the protista kingdom, plantae kingdom, anamalia kingdom and fungi kingdom

• plants are autotrophs and sexual

• fungi are heterotrophs and sexual

• protists are sexual or asexual and are autotrophs or heterotrophs

• animals are heterotrophs and sexual

describe eubacteria domain

• contains eubacteria kingdom

• unicellular (prokaryotic)

• asexual (binary fission)

• heterotrophs or autotrophs

describe archaea domain

• contains archaea bacteria kingdom

• autotroph/heterotroph

• asexual

• unicellular (prokaryotic)

what’s the positive impact of fungi on plants

• fungi has symbiotic relation with plants

• plants rely on fungi to decompose dead matter into nutrients

• these nutrients are key for the fungi

• mutual symbiotic relation

what’s the negative impact of fungi on plants

• when there’s fungal growth around a tree, it can stunt the tree’s growth by affecting its soil