U4 bio: micro/macro evolution

0.0(0)
studied byStudied by 0 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Get a hint
Hint

describe the evolution of eurkaryotes from the first primitive prokaryotes

Get a hint
Hint

the first cells were there 3.7 BYA in stromatolites

1. these cells were anerobic heterotrophic prokaryotes that used fermentation (anerobic process) to remove small amounts of energy from glucose and other sugars in the absence of oxygen

  • there is a shortage of nutrients for the primitive prokaryotes → means an autotroph needs to develop

2. early autotrophs broke down H2S using chemical energy and sunlight

  • then there is a shortage of H2S and organisms capable of breaking down H2O formed because there was a lot of water

3. autotrophs 2.0: can break down water

  • this makes the environment aerobic

  • aerobic processes evolved:

    • cellular respiration

    • aerobic metabolism

  • this changing environment meant heterotrophs needed to find food differently

4. increase in protiens needed for heterotrophs in order to find food, eat and process food

  • more protiens means more DNA needed to make the new proteins

5. evolution of the nucleus (protects DNA)

6. eukaryotes evolved 2bya → true nucleus = eukaryote

Get a hint
Hint

how did other membrane bound organelles evolve

Get a hint
Hint

these evolved as the membrane took different shapes and pinched in forming internal compartments where chemical processes could take place, becoming their own distinct membrane bound organelles

Card Sorting

1/48

Anonymous user
Anonymous user
encourage image

There's no tags or description

Looks like no tags are added yet.

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

49 Terms

1
New cards

describe the evolution of eurkaryotes from the first primitive prokaryotes

the first cells were there 3.7 BYA in stromatolites

1. these cells were anerobic heterotrophic prokaryotes that used fermentation (anerobic process) to remove small amounts of energy from glucose and other sugars in the absence of oxygen

  • there is a shortage of nutrients for the primitive prokaryotes → means an autotroph needs to develop

2. early autotrophs broke down H2S using chemical energy and sunlight

  • then there is a shortage of H2S and organisms capable of breaking down H2O formed because there was a lot of water

3. autotrophs 2.0: can break down water

  • this makes the environment aerobic

  • aerobic processes evolved:

    • cellular respiration

    • aerobic metabolism

  • this changing environment meant heterotrophs needed to find food differently

4. increase in protiens needed for heterotrophs in order to find food, eat and process food

  • more protiens means more DNA needed to make the new proteins

5. evolution of the nucleus (protects DNA)

6. eukaryotes evolved 2bya → true nucleus = eukaryote

2
New cards

how did other membrane bound organelles evolve

these evolved as the membrane took different shapes and pinched in forming internal compartments where chemical processes could take place, becoming their own distinct membrane bound organelles

3
New cards

explain the theory of endosymbiosis

primary and secondary endosymbiosis

when a larger cell takes in a smaller cell by a process called endocytosis, so the smaller cell is inside a vesicle in the cytoplasm of the larger cell

gives the smaller cell protection

gives the larger cell energy made by smaller cell

endosymbiosis is thought to have occured 2x:

primary endosymbiosis: the anerobic heterotroph eats aerobic prokaryote → mitochondria

secondary endosymbiosis: aerobic heterotrophs eats autotrophic photosynthetic prokaryote →chloroplasts

4
New cards

explain the support for the theory of endosymbiosis in the evolution of mitochondria and chloroplasts (4)

  • grow and divide indepently of the cell in which they exist

  • have no nucleus, just a naked loop of DNA

  • make some of their own protiens using 70S ribosomes like prokaryotes

  • have double membranes → from being engulfed in a vesicle

5
New cards

when did organisms evolve to become multicellular

750 mya

6
New cards

what was the cambrian explosion

what factors allowed it to happen?

rapid period of speciation and diversification that took place about 541 mya

increase in oxygen, more nutrients available and more predators which drove prey to evolve faster and imrpove their defenses

7
New cards

what are the 2 speeds in which evolution can take place?

gradualism: small genetic changes that occur over time

punctuated equilibrium: sudden evironmental changes that produce rapid evolution → rapid speciation

8
New cards

Does evolution occur due to small changes over time, large environmental shifts, or both?

Both.

  • Gradualism: Evolution occurs through the accumulation of small genetic changes over long periods of time.

  • Punctuated Equilibrium: Sudden environmental changes (like climate shifts, disasters, or new habitats) can cause rapid speciation events.

9
New cards

What makes organisms within a species different from other species?

Organisms within a species:

  • Can interbreed and produce fertile offspring.

  • Share similar genetic and physical characteristics.

10
New cards

What do we call it when a new species is formed?

Speciation

Speciation is the process by which new species evolve from a common ancestor.

  • Can happen due to geographic isolation (allopatric speciation), behavioral changes, or genetic divergence.

11
New cards

microevolution vs macroevolution:

  • definitions

  • time scale

  • processes involved

  • scope

Feature

Microevolution

Macroevolution

Definition

the changes in allele frequency within a population

Large-scale evolutionary changes that result in the formation of new species or higher taxonomic groups

Time scale

Short-term (within a few generations)

Long-term (thousands to millions of years)

Examples

- Antibiotic resistance in bacteria- Color variation in moths- Beak size changes in finches

- Evolution of birds from dinosaurs- Speciation of humans and chimpanzees from a common ancestor

Processes involved

- Mutation- Natural selection- Gene flow- Genetic drift

- All of the above, plus- Speciation- Mass extinction- Adaptive radiation

Scope

Affects allele frequencies within a single population

Affects entire lineages and may span across multiple species

microevolution = small genetic changes within a species

macroevolution = accumulation of those changes over time that leads to new species or groups

12
New cards

what are the 5 aspects of evolution?

  1. adaptations

  2. movement (gene flow)

  3. mutations

  4. non random mating

  5. small population

13
New cards

what are the mechanisms of microevolution: (5)

  1. bottleneck effect

  2. mating and sexual reproduction

  3. mutation

  4. gene flow

  5. natural selection

14
New cards

what is the bottleneck effect and founder effect

theres a large population that becomes a small population because of:

  • a natural disaster

  • a small group breaks off to form a new population

this forms a new population which might have a completely different allele frequency that the original population → this is changes in allele frequency = microevolution

15
New cards

explain how mating and sexual reproduction is a mechanism for microevolution

non random mating (selects more desirable traits) and secual reproduction introduce new genetic combinations into a population → this creates changes in the allele frequency which is microevolution

16
New cards

explain how mutation is a mechanism of microevolution

random changes to the nucelotide sequence can cause a new trait/ aka allele to occur which can change the allele frequency of the population (if beneficial) = microevolution

17
New cards

explain how gene flow is a mechanism of microevolution

gene flow is the immigration of new genes (it can happen when new populations immigrate)

new organisms into a population can change the allele frequency resulting in microevolution

18
New cards

how is natural selection the “ultimate” determiner of microevolution

in other words how would it differ from the other 4 mechanisms of microevolution?

the other 4 mechanisms of microevolution: sexual reproduction, mutation, gene flow and bottleneck/founder effect produce VARIATIONS that are beneficial to the organism and increase their changes of reproducing and surviving in THAT specific environment

however natural selection is the only mechanism that creates adaptation

  • how does natural selection create adaptations?

    • through determining what genes are fit to be passed on in a specific environment

19
New cards

what is darwinian fitness?

components of darwinian fitness (4)

it is how does natural selection determine what genes are fit to be passed on:

genes are fit to be passed on when they are successful in helping an organism be successful reproductively and pass its genes onto the next generation

components:

  • ability to attract a mate

  • ability to accomplish mating

  • ability to produce fertile offspring

  • ability to raise young to the age of mating

20
New cards

ability to attract a mate:

  • biologically

  • physiology

  • behaviourally

Biologically: colours, symmetry

Physiology: smell, pheremones

Behaviourally: songs, dances, words, “dating”

21
New cards

ability to accomplish mating

Biologically: correct body parts to perform mating

Physiology: make gametes that can fertilize one another

Behaviourally: know how to accomplish mating

22
New cards

ability to produce mature fertile offspring

Biologically: gametes fuse to produce a viable zygote, embryo and newborn

Physiology: allow fetus to develop inside of body or create a self-sustaining egg...

Behaviourally: tailor behaviour for benefit of fetus, incubate eggs

23
New cards

ability to raise young to age of maturity

Biologically: able to give birth and carry young/care for

Physiology: can make milk, has hormones to maintain parenting

Behaviourally: defending young, teaching young to survive

24
New cards

are there different types of natural selection? why?

microevolutionary changes can lead to different types of natural selection:

  • stabilizing selection: favors intermediate traits, reduces variation and maintains the status quo (ex. human birth weight)

  • directional selection: favors traits at one extreme of a distribution leading to a shift in the allele frequency of a population overtime

  • diversifying selection: favors traits at both extremes of allele distribution and intermediates are less likely to survive (ex. darker and lighter shells are better camoflagued compared to intermediates)

25
New cards

what is sexual selection

In biology, sexual selection is a form of natural selection where individuals with certain traits have a higher reproductive success than others due to their ability to attract mates or compete with rivals. It can be driven by two main processes: intrasexual selection (competition within the same sex) and intersexual selection (mate choice by one sex). 

there are 2 main reasons why members of one sex need to be selected:

  • the members of one sex are attracted to specific traits of the other sex, these traits show darwinian fitness

  • the members of one sex need to outcompete the other members to reproduce

26
New cards

why is sexual selection different from regular natural selection types

natural selection = survival oriented (improves the individuals chances of surviving and reproducing in an environment)

sexual selection = increases the individuals ability to attract a mate and reproduce only!

Natural selection can lead to traits that improve survival and overall fitness, while sexual selection can lead to traits that are primarily beneficial for mating, even if they compromise survival. 

27
New cards

how could sexual selection compromise individuals survival

Can lead to exaggerated traits (like huge tails or loud calls) that don’t help with survival and might even be risky — but improve chances of reproducing.

28
New cards

what is it called when sexual selection results in differences between the appearances of males and females

sexual dimorphism

this is when there are distinct differences in size or appearance between the sexes of an animal

29
New cards

types of sexual selection (2)

male male competition (intrasexual selection):

  • Members of the same sex compete with each other for access to mates.

  • Often involves male-male competition for dominance or territory.

    • this happens when resources are concentrated, so there is an aspect of territory and using access to resources to attract mates

  • Traits selected: size, strength, aggression, antlers, etc.

female choice (intersexual selection):

  • when resources are dispersed and mates could be anywhere

  • One sex chooses a mate based on specific traits.

  • Often females choose males with showy, impressive features or behaviors. → show that they are the healthiest and most attentive mates

  • Traits selected: bright colors, long tails, complex songs, dancing, etc.

30
New cards

what is artificial selection

when humans make choices that lead to microevolutionary changes, in other words, humans artificially select what traits a population should have

31
New cards

hardy weinberg principle → law of genetic equilibrium

The Hardy-Weinberg Principle is a mathematical model used to study how populations evolve (or don’t) over time.

📌 Key Idea:

If certain conditions are met, the frequency of alleles and genotypes in a population will remain constant over generations.
This means the population is not evolving — it is in genetic equilibrium.

conditions for no evolution/ genetic equilibrium:

  1. No mutations

  2. No natural selection

  3. Large population size

  4. No migration (gene flow)

  5. Random mating

32
New cards

why are hardy weinberg equations important

  • Used as a baseline: If a population doesn’t match Hardy-Weinberg predictions, it means evolutionary forces are acting on it.

  • It helps scientists detect natural selection, mutations, or gene flow in real populations.

33
New cards

define macroevolution

macroevolution is an evolutionary change that causes a speciation event which is the formation of a new species

34
New cards

mechanisms for macroevolution (how do these these large scale changes occur?)

gradually → compounded microevolutionary changes which results in big differences between a species and their ancestors until they are unable to mate → forms new species = macroevolution

abruptly → environmental pressures (like volacno eruption, meteor etc.) cause rapid natural selection

35
New cards

a) what is polyploidy

b) how is polyploidy connected to macroevolution and the formation of a new species?

a) when an organism ends up with an extra set of chromosomes usually due to an error in meiosis, so instead of halving the chromosome number the cell accidentally duplicates it

b) because polyploidy organisms have a different number of chromosomes, they usually cant mate successfully with the original species → however if the polyploid can survive and reproduce (either asexualy or with other polyploids) it becomes reproductively isolated → instant speciation called sympatric speciation

36
New cards

why does polyploidly result in fast speciation? (aka abrupt speciation)

  • there is no need to wait for the gradual accumulation of genetic changes (accumulation of microevolution)

  • one mutation will result in a new chromosome number and create reproductive isolation

37
New cards

explain the example of speciation in the genus allium (plants) by polyploidy

the genus allium includes monocot flowering plants ex. the onion, garlic, chives, scallion, leeks, shallots

but polyploidly has arose due to chromosome doubling through non-disjunction. this reproductively isolates similar populations which creates many species

38
New cards

what are the benefits of polyploidy in agriculture (4)

  • Makes the population stronger and healthier by mixing more genes, so there's less risk of inherited diseases.

  • Adds more genetic variety, giving the population more options to survive changes.

  • New traits appear more often, helping the population adapt faster and form new species.

  • Leads to bigger flowers, fruits, or roots in plants.

39
New cards

why is it so hard to tell if things are the same species? (4)

  1. asexual reproduction in some organisms

  2. geographical separation of species that can interbreed

  3. formation of hybrids

  4. sexual dimorphism → some members of the same species look very different

40
New cards

what are the 2 main mechanisms of speciation (aka creating a new species through macroevolution)

  • allopatric: geographical isolation

  • sympatric: speciation caused my reproductive isolation within the same geographical area

41
New cards

what is allopatric speciation

when organisms are phsycially separated. memebers of the same species are geographically isolated due to natural or human factors which prevents gene flow between these populations

  • lack of gene flow results in: mutations being unshared

  • also natural selection can place different pressures on the separated populations which can result in different mciroevolutionary changes

  • this can prevent the 2 populations from being able to reproduce even if they are reunited.

42
New cards

sympatric speciation

types (2)

sympactric speciation is when species form due to reproductive isolation within the same geographical location

types:

  • pre zygotic: prevents the zygote from forming

  • post zygotic: prevents the organism from fully developping to mature fertile age (reproductive age)

43
New cards

pre-zygotic isolating mechanisms (4)

  1. Behavioural - never mate because they don’t recognize each others courtship rituals

  2. Temporal - different breeding seasons, diurnal vs. nocturnal lifestyles are unlikely to meet and mate

  3. Geographic - live in different niches within the same environment; aquatic vs. terrestrial

  4. Mechanical - prevent mating OR gamete fertilization

44
New cards

post-zygotic isolating mechanisms

  1. Zygote mortality - misscarriage terminates pregnancy due to gamete incompatibility

  2. Hybrid inviability - offspring are weak or don’t survive to age of reproduction

  3. Hybrid infertility - offspring are infertile and cannot reproduce

45
New cards

patterns/trends of speciation (2)

convergent:

  • different ancestors

  • analogus structures

  • becomes more and more similar

divergent:

  • same ancestor, but they evolved to be different species

  • homologus structures

  • becomes more and more different

46
New cards

adaptive radiation

Definition:
Adaptive radiation is when one species rapidly evolves into many new species, each adapted to a different environment or way of life.

Key Points:

  • Happens when new environments or resources become available.

  • Species evolve to fill different ecological niches (roles in the environment).

  • Driven by natural selection — traits that help survival in a niche become more common.

🐦 Example:

  • Darwin’s finches in the Galápagos Islands:

    • All evolved from a common ancestor.

    • Developed different beak shapes to eat different types of food (seeds, insects, etc.).

47
New cards

co-evolution/parallel evolution

essientially when 2 species have a relationship (symbiotic or parasitic) or are closely linked, when one evolves the other will evolve too, this is called parallel evolution between the 2 species.

48
New cards

what is genetic drift? how is it related to the bottleneck/founder effect?

Definition:
Genetic drift is a
random change in the frequency of genes in a population, especially in small populations.

Key Points:

  • Not caused by natural selection — it’s luck-based.

  • Can cause loss of genetic diversity.

  • Sometimes, rare traits can become common just by chance.

🎲 Example:

  • If a natural disaster randomly kills most of a population, the survivors might not represent the original gene pool. This is called a bottleneck effect.

  • Or when a few individuals start a new population (founder effect), their genes dominate the new group.

49
New cards

what is hybridization?

Hybridization is when individuals from 2 different species or distinct populations interbreed and produce offspring (these are hybrids)

  • if the hybrids are fertile and can reproduce, hybridization can lead to new gene combinations and sometimes new species → speciation

  • think ancient humans and neanderthals interbreeding to form modern humans (hybrids)