sbi3u_flashcards_-_unit_2_-_evolution_20250612000339

Question 1

Neutral mutation

Answer 1

Mutation that does not result in any selective advantage or disadvantage; provides no benefit or harm to the individual

Question 2

Harmful mutation

Answer 2

Mutations that reduce the reproductive success of an individual and is therefore selected against. They do not accumulate over time.

Examples: Cystic fibrosis, Huntington’s disease

Question 3

Beneficial mutation

Answer 3

Mutations that increase the reproductive success of an organism and is therefore favoured. They accumulate over time.

Example: Sickle-cell allele gives carriers high resistance to malaria and increases their chances of survival

Question 4

Artificial selection

Answer 4

Directed breeding in which individuals with specific traits are chosen as parents of the next generation

Examples: Dog breeding from wolves & wild sea cabbage producing broccoli, cauliflower, cabbage, kale, etc.

Question 5

Advantages and disadvantages of artificial selection

Answer 5

Advantages: Can mass produce desired animal/plant species, beneficial mutations has positive consequences for species

Disadvantages: Reduces genetic diversity which contributes to the loss of biodiversity, cannot create traits that don’t already exist

Question 6

Inheritance of acquired characteristics

Who created it? What is it?

Answer 6

Created by Jean-Baptiste Lamarck

Individuals could pass on characteristics they had acquired during their lives to their offspring

[Also proposed that all species evolve over time and in response to its environment, becoming better adapted in that environment. Also, changes are passed from generation to generation.]

Question 7

Catastrophism

Who created it? What is it?

Answer 7

Created by Georges Cuvier

Global catastrophes (like floods) caused the widespread extinction of species

Question 8

Uniformitarianism

Who created it? What is it?

Answer 8

Created by Charles Lyell

Geological changes are slow & gradual, and natural laws/processes have not changed over time

Question 9

Evolution by Natural Selection

Who created it? What is it?

Answer 9

Created by Charles Darwin

Process in which species change over time to best adapt to their environments

Question 10

Darwin’s observations

Answer 10

• Similar flora (plants) & fauna (animals) on the Galapagos as on mainland South America
• Many distinct species of finches & mockingbirds
• Fossilized species were similar to present-day species. Ex. Glyptodon (armadillo) & megatherium (sloths)

Question 11

Fossil record

Answer 11

Historical, chronological record of all-known fossils documenting life on Earth and the evidence of past life

Question 12

Evidence in fossil record

Answer 12

• There are fossils of those no longer living
• Shallow layers resemble living species
• No fossils of most living species
• The deeper layers you get, the more simple the fossils are
• Fossils are buried deep within rock formations; also, they are found in unexpected locations. Ex. Sea life fossils found in mountain formations & deserts

Question 13

Biogeography

Answer 13

Scientific study of geographic distribution of organisms based on both living species & fossils

Question 14

Homologous features

Answer 14

Common origin/structure, but different function

Question 15

Analogous features

Answer 15

Common function, but different structure

Question 16

Vestigial features

Answer 16

Has homologous structure to another species, but it serves no purpose in this species

Question 17

Competitions within populations

Answer 17

Competition within populations, or intraspecific competition, occurs when members of the same species compete for limited resources, leading to reduced fitness and survival for some individuals.

Basically small environment + limited food supply = population cannot grow indefinitely & competition to survive

Question 18

Natural selection

Answer 18

The way in which nature favours the reproductive success of some individuals within a population over others

Question 19

Adaption

Answer 19

Characteristic/feature of species that makes it well suited for survival or reproductive success in its environment

Question 20

Directional selection

Answer 20

Selection that favours a more extreme variation of a trait

Ex. Longer-billed birds are favoured in long-flower environments

Question 21

Stabilizing selection

Answer 21

Selection that favours the average phenotype (favoured by the environment; extreme variations are not favoured)

Ex. Average-length billed birds are favoured

Question 22

Disruptive selection

Answer 22

Selection that favours opposite extremes of a trait

Ex. Small & large billed birds favoured where there are small & large flowers, both not well-suited for medium-length billed birds

Question 23

Sexual selection

Answer 23

Selection that favours the reproductive success of individuals with certain traits over others

Question 24

Genetic drift

Answer 24

Random shifting of genetic makeup of next generation (chance). Can result in an allele becoming very common or disappearing entirely.

Question 25

Genetic bottleneck

Answer 25

Dramatic (often temporary) reduction in population size, usually resulting in genetic drift. - Usually the population is all genetically similar

Question 26

Founder effect

Answer 26

Genetic drift that happens when a small number of individuals establish a new population

Question 27

Human influence on natural selection?

Answer 27

Hunting can make animals extinct, lose size (fish), lose tusks (elephants), make bedbugs more resistant to pesticides

Question 28

Speciation

Answer 28

Formation of new species

Question 29

Species

Answer 29

All members of a population that can interbreed under natural conditions

Question 30

Allopatric speciation

Answer 30

Formation of new species from geographic separation. These species eventually become less and less genetically related as evolution goes on. Ex. Pacific wrasse and caribbean wrasse cannot interbreed due to a thin strip of land called the Isthmus of Panama dividing the wrasse species 2 million years ago.

Question 31

Sympatric speciation

Answer 31

Formation of new species within the same geographic area. Can occur due to competition for resources or mutations. Disruptive selection can lead to this speciation. Ex. Hawthorn flies laying eggs on both hawthorns & apples after apple trees were brought over to North America.

Question 32

Reproductive isolating mechanism

Answer 32

Any behavioural/structural/biochemical trait that prevents individuals of different species from reproducing successfully together

Question 33

Prezygotic mechanism

Answer 33

Prevents interspecies mating & fertilization (formation of zygotes)

Question 34

Postzygotic mechanism

Answer 34

Prevents maturation & reproduction in offspring from interspecies reproduction (prevents zygote from becoming a viable & reproducing adult)

Question 35

Behavioural isolation Pre/Post? Desc.? Ex.?

Answer 35

Prezygotic mechanism Different species use different courtship and other mating cues to find and attract a mate. Ex. Male frogs of different species have unique calls that attract only females of their own species.

Question 36

Hybrid infertility Pre/Post? Desc.? Ex.?

Answer 36

Postzygotic mechanism Hybrid offspring remain healthy and viable, but are sterile. Ex. Mules are the sterile hybrid offspring of a horse-donkey cross.

Question 37

Mechanical isolation Pre/Post? Desc.? Ex.?

Answer 37

Prezygotic mechanism Differences in morphological features may make two species incompatible. Male damselflies transfer sperm during an unusual mating flight. The male and female genitalia of each species are uniquely shaped and are physically incompatible with other species.

Question 38

Zygotic mortality Pre/Post? Desc.? Ex.?

Answer 38

Postzygotic mechanism Mating & fertilization are possible, but genetic differences result in a zygote that is unable to develop properly. Some species of the sheep and goat are able to mate, but the zygote is not viable.

Question 39

Temporal isolation Pre/Post? Desc.? Ex.?

Answer 39

Prezygotic mechanism Different species breed at different times of the year. Pussy willow produce flowers in the early spring. They are reproductively isolated from plant species that produce flowers at a different time of the year.

Question 40

Hybrid inviability Pre/Post? Desc.? Ex.?

Answer 40

Postzygotic mechanism A hybrid individual develops but either dies before birth or, if born alive, cannot survive to maturity. When tigers and leopards are crossed, the zygote begins to develop but the pregnancy ends in a miscarriage or stillborn offspring.

Question 41

Ecological isolation Pre/Post? Desc.? Ex.?

Answer 41

Prezygotic mechanism Very similar species may occupy different habitats within a region. The mountain bluebird lives at high elevations, while the eastern bluebird prefers lower elevations and does not encounter the mountain species.

Question 42

Gametic isolation Pre/Post? Desc.? Ex.?

Answer 42

Prezygotic mechanism Male gametes may not be able to recognize and fertilize an egg of a different species. Many marine animals including corals, clams, and sea cucumbers release their sperm and eggs into open water. The sperm recognizes eggs of their own species through chemical markers on the surface of the eggs.

Question 43

Adaptive radiation

Answer 43

When a single species rapidly evolves into many different species, filling formerly empty ecological niches. Ex. Finches

Question 44

Divergent evolution

Answer 44

Large-scale evolution of a group of organisms into many different species, filling specialized ecological niches. Ex. Rodents in Ontario; deer mouse, flying squirrel, beaver

Question 45

Convergent evolution

Answer 45

Evolution of similar traits in distantly related species (analogous features). Ex. Cacti in South America & Africa

Question 46

Co-evolution

Answer 46

Process where one species evolves in response to the evolution of another species. Ex. Hawkmoth & star orchid

Question 47

What is the name of the theory that states that geological changes are slow and gradual and that natural laws and processes have not changed over time? Which scientist is associated with this theory?

Answer 47

Uniformitarianism; Charles Lyell

Question 48

What is the name of the theory that states that the pattern of fossils could be accounted for by a series of global disasters that wiped out most species on Earth? Which scientist is associated with this theory?

Answer 48

Catastrophism; Georges Cuvier

Question 49

Which part of Jean-Baptiste Lamarck's theory does not fit with Charles Darwin's theory of evolution by natural selection?

Answer 49

Jean-Baptiste Lamarck proposed that characteristics acquired during an individual organism's lifetime are passed on to their offspring. (Charles Darwin proposed that the characteristics are already present due to natural variations; if they are adaptive, they will be passed on in greater proportion to the next generation)

Question 50

During his trip on the HMS Beagle, what observations did Charles Darwin make with regard to biogeography?

Answer 50

Charles Darwin observed that fossil species that were similar to living species had the same geographical pattern of distribution (biogeography), suggesting that the living species had evolved from these fossil species.

Question 51

Name 2 unique species found on the Galapagos islands & describe what is unique about each of them

Answer 51

Marine iguana - No other aquatic iguana species in the world Flightless cormorant - No other species of cormorant that does not fly

Question 52

The forelimbs of the human, horse, cat, bat, and whale have very similar bone structure, but they are adapted to carry out very different functions. This is an example of a _____ feature. What inference can be made about these organisms?

Answer 52

Homologous; can infer that they have common evolutionary origin (ex. a common ancestor)

Question 53

The extra toes on pigs' feet that do not touch the ground are examples of ______ features. What inference can be made about the existence of these features?

Answer 53

Vestigial; can infer that the pigs descended from an ancestral species where the toes were used

Question 54

The wings of birds & the wings of butterflies are both broad, thin, light, and well adapted to their function of flight. They are examples of ____ features. What inference can be made about the mechanism of evolution of these kinds of features?

Answer 54

Analogous; can infer that a similar function (or environment) can lead to similar characteristics developing in organisms that are distantly related

Question 55

The evolution of antibiotic resistance in bacteria is an example of ______ selection. The selective breeding of dog breeds is an example of ___ selection.

Answer 55

Natural; Artificial

Question 56

Cheetahs have very little genetic diversity because their population was reduced to just 7 individuals 10000 years ago. This is an example of the _______ effect.

Answer 56

bottleneck effect

Question 57

The human population of Iceland was started with a relatively small initial population (primarily of Norwegian, Scottish, and Irish origin) more than 1000 years ago. This is an example of the ___________________ effect.

Answer 57

founder effect

Question 58

Over many generations, a population of hummingbirds gradually has longer and longer bills (beaks). This is an example of ___________________ selection.

Answer 58

directional

Question 59

Over many generations, a population of hummingbirds has an even greater percentage of individuals with bills of an average length. This is an example of ___________________ selection.

Answer 59

stabilizing

Question 60

Over many generations, a population of hummingbirds gradually has longer and longer bills, that allow them to feed on certain flowers that have extremely long nectar tubes. This is an example of what pattern of evolution?

Answer 60

coevolution

Question 61

Give an example of a human genetic mutation that is beneficial in some circumstances, but harmful in others. What determines if a mutation is beneficial?

Answer 61

The sickle cell anemia allele is generally harmful because it affects the health of the individual; in areas of Africa where malaria is prevalent it can be beneficial because presence of the allele gives the individual resistanct to malaria. The environment determines if a mutation is beneficial or harmful.

Question 62

What are the 2 most common forms of sexual selection?

Answer 62

female mate selection (females choosing males to mate with) & male-versus-male competition (males competing with each other for territory & access to females for mating).

Question 63

If a population evolves into separate species while within the same geographic area, it is called ___________________ speciation.

Answer 63

sympatric

Question 64

The evolution of a single species into many new species, filling a variety of formerly empty ecological niches is called ___________________ or ___________________.

Answer 64

adaptive radiation or divergent evolution

Question 65

The similar body shapes of sharks and dolphins (even though they are not closely related) is an example of ___________________ evolution.

Answer 65

convergent

Question 66

Male frogs of different species have unique calls that attract only females of their own species. This is an example of ___________________ isolation, which is a ___________________ reproductive isolating mechanism.

Answer 66

behavioural; prezygotic

Question 67

Zebroids, the hybrid offspring of matings between horses and zebras, cannot reproduce. This is an example of ___________________ which is a ___________________ reproductive isolating mechanism.

Answer 67

hybrid sterility; postzygotic