Evolution Part 2

Question 1

Bottleneck Effect

Answer 1

A dramatic, often temporary reduction in the population size (Event that reduces population)

This causes changes in frequencies in populations

Though this is all determined by chance

Question 1

Genetic Drift

Answer 1

• Known as the pinky finger

A change in the genetic makeup of a population due to pure random chance

(More expressed in small populations)

Question 2

Founder Effect

Answer 2

When few individuals from a larger population leave to establish a new population
(Will not be same as original)

Question 3

Gene Flow

Answer 3

• Known as pointer finger
  When organisms migrate/emigrate which causes change in the frequencies in the gene pool of the population

Question 4

Non-Random Mating

Answer 4

• Known as ring finger
  Mates with preferred traits will pass on their alleles more commonly other than mates that are less preferred

Question 5

Genetic Mutations

Answer 5

• Known as middle finger
  Mutations are the only sources of new genetic material and new alleles. They can pass on their alleles depending on the types.

Question 6

Types of mutations

Answer 6

Neutral: No effect on individual

Harmful: Result in death or lack/disability to produce (most likely won’t pass down)

Beneficial: very rare; involves new improved protein (Gives advantage

Question 7

Natural selection

Answer 7

• Known as thumb
  Those better able to survive in the environment have greater reproductive (Survival) success which increases frequencies.

Question 8

Modes of Natural selection

Answer 8

there are 3 types of natural selection

• stabilizing
• directional
• disruptive

Question 9

Directional Selection

Answer 9

one extreme is selected for while the other is not

ex: long legs are better 4 horses

Question 10

Disruptive Selection

Answer 10

Both extremes are selected for

ex: not much medium coloured moths

Question 11

Stabilizing Selection

Answer 11

Neither extremes are selected for (middle is best)

Question 12

Artificial Selection

Answer 12

involves intentional or selective breeding for certain traits, or combination of traits that benefit mankind.

Question 13

Advantages & Disadvantages of Artificial Selection

Answer 13

Advantages:
- Increased production
- Increased nutritional content
- Lower production costs
- Increased resistance to disease
- Lower pesticide use

Disadvantages:
- Less genetic variability
- Less biodiversity
- Seeds are patented so cost more money
- Focus on 1 trait, but can be lacking in others (flowers)

Question 14

Gradualism

Answer 14

When species first evolve, they are still similar to the original.

Species slowly evolve over time which takes a long time for the species to be totally different from its originator

Slow incremental changes over time

Expect transitional fossils

Question 15

Punctuated Equilibrium

Answer 15

Species may evolve rapidly with large changes followed by long periods of little or no change

explains the reasoning behind not all transitional fossils being found

Usually happen in small isolated populations

Beneficial mutations are one source of change

Question 16

Divergent evolution

Answer 16

A pattern of evolution in which species that were once similar to an ancestor end up diverging (branch off)

–> This type of evolution could be caused by the different selective pressures in an environment overtime

• occurs when populations change as they adapt to different conditions

Question 17

Adaptive Radiation

Answer 17

Adaptive radiation is a form of divergent evolution where members of an ancestral group of organisms move to a new area and diversify under the new selective pressures

Question 18

Convergent evolution

Answer 18

A pattern of evolution in which unrelated species from different ancestors independently evolve to have similar traits, due to similar environmental conditions and selective pressures

Not because of shared ancestry

ex: fly wings vs bat wings

Question 19

Co-Evolution

Answer 19

One species evolves in response to another species

Both species are completely dependent on each other for their survival

Question 20

Biological Species

Answer 20

Population of individuals that can interbreed to create viable and fertile offspring

Question 21

Allopatric Speciation

Answer 21

physical barrier (river or canyon) that is created to separate populations from each other which causes the frequency of the population to change due to natural selection (since both populations can no longer interact with each other)

Example: Volcanic eruptions, flood -> river

Question 22

Sympatric Speciation

Answer 22

The species share the same territory though they do not mate

Causes:
Differences in behaviour or appearance
Polyploidy: one species may have more chromosomes than the other, but they have the same ancestor

Example: Humans (46 chromosomes) & Chimpanzees (48 chromosomes)

Question 23

Pre-zygotic

Answer 23

Before the egg gets fertilized (zygote gets produced) results in prevention of mating or fertilization

Question 24

Types of Isolation

Answer 24

Prevention of mating
Ecological isolation
Live in different habitats
Example: Aquatic vs terrestrial plants

Temporal isolation
Separation of timing
Example: Owls vs Hawk 2 uhh

Behavioural isolation
Different mating behaviours
Example: Birds with dances

Question 25

Prevention of fertilization

Answer 25

Mechanical
Different reproductive organs
Example: Pig PENIS
Gametic

Diffrent proteins in the gametes that don’t allow fertilization to occur

Question 26

Post-zygotic

Answer 26

Hybrid inviability: Hybrid zygote doesn’t develop properly (Sheep + goat)

Hybrid sterility: Hybrid offspring being infertile (Horse + donkey)

Hybrid breakdown - first gen hybrid is fertile and viable

Question 27

Artificial Selection vs Natural Selection

Answer 27

Natural selection: Survival and reproduction of organisms best adapted to their environment.

Mechanism: Variation in traits within a population, competition for resources, differential survival and reproduction.

Example: Rabbits with better camouflage evade predators more successfully.

Driving force: Environmental pressures.

Outcome: Populations adapt to their natural environment.

Artificial selection: Intentional breeding of organisms by humans for desired traits.

Mechanism: Humans select individuals with preferred traits to reproduce.

Example: Dog breeding for specific sizes, temperaments, or appearances.

Driving force: Human preferences.

Outcome: Traits may not confer survival advantages in the wild.

Key differences: Natural selection is driven by nature and promotes adaptation; artificial selection is driven by human choice and can lead to non-adaptive traits.