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Question 1

Natural Selection

Answer 1

is the process by which organisms with heritable traits that are better adapted to their environment tend to survive and produce more offspring
- leads to changes in Allele Frequencies over time
- Evolution Change occurs when Allele Freqs of a population change over successive generations due to differential survival and reproduction

Question 2

Fitness

Answer 2

refers to an individual’s ability to survive and reproduce in a specific environment
- individuals with more fitness r more likely to pass on their Alleles to the next gen

Question 3

Adaptation

Answer 3

is the process by which a population becomes better suited to its environment over many generations
- This occurs through natural selection acting on heritable variation

Question 4

Genetic Variation

Answer 4

refers to the differences in DNA sequences among individuals in a population which can lead to differences in expressed traits

sources:
Mutation
Recombination
Random Fertilization

w/o G.V N.S would not occur as their would be no differences in gene expression or DNa sequence.
Gene Variation provides the raw material in which natural selection acts on.

Question 5

Selection Pressure

Answer 5

is any factor in the environment that affects the survival and reproduction of individuals with certain heritable traits
- Predation
- Competition
- Disease
- Abiotic factors (temperature, availability of resources)

whatever selection pressure favors, that allele will be common.

Question 5

Directional Selection

Answer 5

occurs when one extreme of a trait is favored, causing the mean value of the trait to shift in that direction over time
- example is the evolution of taller plants in response to competition for light
- Directional selection reduces variation in a population

Question 6

Stabilizing selection

Answer 6

occurs when intermediate values of a trait are favored, causing the population to become more homogeneous around the mean value of the trait
- example is the selection for average birth weight in humans, as both very low and very high birth weights have lower fitness
- Stabilizing selection reduces variation around the mean value of a trait
Disruptive selection

Question 7

Hardy-Weinberg model

Answer 7

no mutations, no gene flow, random mating, a large population size, and no natural selection.
- Random mating results in no change in allele frequencies over time, as there is no preferential selection of certain alleles or genotypes
- In large populations, genetic drift is assumed to be negligible, as random changes in allele frequencies have minimal impact (genetic bottlenecks, founder effects)

Question 7

Disruptive selection

Answer 7

occurs when both extremes of a trait are favored over intermediate values
- the population to become more variable and potentially leads to the formation of two distinct subpopulations
- increases variation in a population
Comparing the types of selection

Question 8

Artificial selection

Answer 8

is the process by which humans select for desirable traits in organisms, such as plants and animals, to produce offspring with those desired characteristics
- Selective Breeding
- better stuff; bigger crops; more milk producing animals; larger animals

Question 9

Selective Breeding

Answer 9

where individuals with the desired traits are chosen to reproduce, while those lacking the desired traits are not allowed to breed

Question 10

No Mutation, Migration, or Selection

Answer 10

No mutation maintains existing allele frequencies
No introduction of new Alleles
No differential survival or reproduction of certain Alleles.

Question 11

Hardy Weinberg Equlibrium

Question 12

Genetic Drift

Answer 12

is the random change in allele frequencies due to chance events rather than selection
- stronger effect in smaller populations
- can lead to loss Alleles.
- acts randomly
-

Question 13

Bottleneck effect

Answer 13

is a dramatic form of genetic drift that occurs when a population is drastically reduced in size due to a catastrophic event.
- genetic diversity in the original population is lost because the few surviving individuals carry only a small sample of the original genetic variation.
- reduce genetic diversity
- higher rates of genetic disorder
- decreased ability to adapt.

Question 14

Founder Effect

Answer 14

occurs when a small group of individuals separates from a larger population and establishes a new, isolated population
- Founders only carry a small pool of the genetic diversity from original. Becomes the basis for the new population

Question 15

Gene Flow

Answer 15

the movement of alleles from one population to another when individuals or their gametes travel between populations.
- increases genetic diversity
- can counteract the effects of gene flow

Question 16

Speciation

Answer 16

Speciation is the evolutionary process where a population of a species becomes so genetically distinct from another population that they are no longer able to interbreed and produce fertile offspring, effectively creating new species

Question 17

Problems of reduced genetic diversity

Answer 17

• The population may become more vulnerable to environmental changes
• Harmful recessive alleles may become more common
• The population may show less phenotypic diversity
• Differences between separate populations of the same species may increase

Question 18

Process of speciation

Answer 18

Population separation: Geographic barriers prevent gene flow between populations

Genetic divergence: Mutation, genetic drift, and natural selection cause the populations to become genetically different

Reproductive isolation: Genetic differences lead to barriers that prevent successful interbreeding

Speciation: The populations become distinct species that cannot produce viable offspring together

Question 19

Beneficial Mutations:

Answer 19

Beneficial mutations are changes in an organism’s genetic material that improve its chances of survival and reproduction.

Question 20

Deleterious Mutations:

Answer 20

Deleterious mutations are harmful changes in an organism’s genetic material that decrease its chances of survival and reproduction.

Question 21

Drawings theory in 3 main parts

Answer 21

• Species change over time
• Different species share common ancestors
• Natural selection drives these changes

Question 22

Evidence of Evolution

Answer 22

1. Fossils: The fossil record provides a historical record of the gradual changes that have occurred in organisms over time. This evidence supports the idea that species have evolved through time and that modern organisms have evolved from ancestral species.
2. Biogeography: The distribution of species across the Earth can provide clues about their evolutionary history. For example, similar species are often found in geographically close areas, while dissimilar species are found in distant areas.
3. Comparative anatomy and physiology: The similarities and differences in the anatomy and physiology of different species can provide clues about their evolutionary relationships. For example, the similarities between the bones of a bat’s wing and a human arm suggest that they share a common ancestor.
4. Biochemistry and molecular biology: The similarities in the biochemistry and molecular biology of different species can provide clues about their evolutionary relationships. For example, the similarities in the genetic code of different organisms support the idea that all living organisms share a common ancestor.

Question 23

Fossil

Answer 23

methods allow paleontologists to piece together the evolutionary history of an organism by comparing its age and characteristics with other fossils found nearby; they can also provide insights into the ancient ecosystems in which these organisms lived and how they evolved over time

Question 24

Vestigial Structures

Answer 24

Anatomical features that no longer seems to have a purpose in the current form of an organism

Question 25

Homologous Structures

Answer 25

Homologous structures are parts of different organisms that have similar structure but not necessarily the same function, indicating a common ances

Question 26

Divergent Evoltuion

Answer 26

Two or more species diverge from a common ancestor

Question 27

Convergent Evolutuon

Answer 27

two or more species share traits not due to a common ancestor

Question 28

Analogous Structures

Answer 28

eatures of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature

Question 29

typically provides more accurate and reliable information than morphological traits because:

Answer 29

- It's less influenced by environmental factors - It can reveal relationships between organisms that look very different - It provides quantifiable data about the degree of difference between species - It can detect evolutionary changes that aren't visible in physical appearance

Question 30

Punctuated equilibrium

Answer 30

It suggests that evolution occurs in fits and starts, with long periods of stasis (little or no change) punctuated by brief periods of rapid evolution. This theory suggests that evolution is not a slow, steady process, but instead occurs in bursts, with most species remaining relatively unchanged for most of their history.

Question 31

gradualism

Answer 31

a model that proposes that evolution is a slow, steady process that occurs over hundreds of thousands or millions of years. This model suggests that evolution is a gradual accumulation of small changes over time, leading to the gradual development of new species.

Question 32

Allopatric Speciation

Answer 32

occurs when two populations become “reproductively isolated” from one another. - s possible that the two separate populations will evolve separately until they are unable to breed with each other.

Question 33

Sympatric Speciation

Answer 33

This is when individuals within the same geographic area are influenced by either disruptive selection or mating preferences - Disruptive selection occurs when two opposing traits are equally favored by nature. As the population begins to evolve oppositely, speciation is likely to occur.

Question 34

Prezygotic vs. Postzygotic Isolation

Answer 34

Prezygotic isolation prevents the fertilization of eggs when two individuals breed, thus making it impossible to reproduce Postzygotic isolation does not allow the formation of a fertile offspring, like in the mule example

Question 35

Things that can cause extinction

Answer 35

- Dramatic climate changes (getting too hot or cold) - Major disasters (volcanic eruptions, asteroid impacts) - Rising or falling sea levels - New predators or competitors - Disease outbreaks - When Extinction Speeds

Question 36

Extinction speed

Answer 36

Happens during times of environmental stress; when conditions change too quickly for species to adapt. - Environments change rapidly - Food sources disappear - Habitats are destroyed - Multiple threats happen at once

Question 37

adaptive radiation

Answer 37

when a single type of organism diversifies into many new species to take advantage of available opportunities. - happens after extinction and ppl need to fill in the new roles

Question 38

hardy Weinberg problem

Answer 38

p^2 = dominant homozygous q^2 = recessive homo 2pq = hetero p = dominant q= recessive

Question 39

Heterochrony

Answer 39

Heterochrony is an evolutionary change in the rate or timing of developmental events.

Question 40

Intrasexual selection

Answer 40

also known as mate competition, is a type of sexual selection where members of the same sex compete with each other for access to mates

Question 41

Temportal Isolation

Answer 41

Species that breed during different seasons, times of the day, or different years cannot mix their gametes.

Question 42

Gametic Isolation

Answer 42

prezyogtic barrier

Question 43

Mechanical Isolation

Answer 43

where physical barriers prevent the fertilization of gametes from different species