Unit 4

Question 1

What is evolution?

Answer 1

Change in the gene pool of a population from generation to generation over time caused by mutations, natural selection, and genetic drift.

Question 2

What did Leclerc de Buffon hypothesize?

Answer 2

He hypothesized that species were created perfect but over time they changed. He studied anatomy and questioned why animals have body parts they don’t use.

Question 3

What were the 2 principles Chevalier de Lamarck hypothesized?

Answer 3

• Use and Disuse: structures an individual used became larger and stronger where passed down while weaker ones that weren’t used were became weaker and smaller
• Inheritance of Acquired Characteristics: individuals could pass characteristics to their offspring what they gained overtime

Question 4

What is the theory of evolution by natural selection?

Answer 4

Darwin described natural selection as a way that the environment favours the reproductive success of certain species over others.
Evolution was simply the result of natural selection occurring over many generations

Question 5

What was Darwin’s Theory?

Answer 5

He observed that all healthy populations produce far more offspring than can survive and all individuals exhibited heritable variability.
From this he concluded:
- Some individuals will have better chance of success than others
- Their traits are more likely to be passed onto the next generation

Question 6

What was Charles Darwin’s adventure?

Answer 6

In December 1831, Charles Darwin set sail on a 5 year trip on the HMS Beagle where he helped survey the coast but used this as an opportunity to study plants and organisms.

Question 7

What did Charles Darwin notice at the Galapagos Islands?

Answer 7

• Noticed nesting babies had no fear of humans
• Iguanas that could dive underwater
• Giant land tortoise
  He collected information from islands in close proximity to each other. When he studies these islands, there were variations within the species and some species were considered separate because they were so different (the finches).

Question 8

What is natural selection?

Answer 8

• Evolution occurs when natural selection acts on genetic variability of a population
• Benefit of the trait for survival and is passed on to the next generation
• Environment favours a certain trait

Question 9

What is directional selection?

Answer 9

Selection is favouring one extreme of the trait over another

Question 10

What is a stabilizing selection?

Answer 10

Majority of the population is taking on the middle of the 2 extreme ends of the trait

Question 11

What is disruptive selection?

Answer 11

Intermediate trait is not favoured but the 2 extreme ends of the trait is favoured

Question 12

What is sexual selection?

Answer 12

• Favouring a trait that enhances the mating success of the organism
• Allows for males or females within the population to evolve in their appearances or behaviours

Question 13

What is genetic drift?

Answer 13

• Change by chance with no selection influence
• No benefit or loss from the trait passing on

Question 14

What is a Genetic Bottleneck?

Answer 14

• No selective pressure but change in frequency of the population
• Loss in genetic diversity due to extreme reduction in the size of population

Question 15

What is Behavioural Isolation?

Answer 15

Different species use different courtship and other mating clues to find and attract a mate.

Question 16

What is temporal isolation?

Answer 16

Different species breed at different times of the year

Question 17

What is ecological isolation?

Answer 17

Very similar species may occupy different habitats within a region.

Question 18

What is mechanical isolation?

Answer 18

Differences in morphological features may make two species incompatible.

Question 19

What is gametic isolation?

Answer 19

Male gametes may not be able to recognize and fertilize an egg of a different species.

Question 20

What is zygotic mortality?

Answer 20

Mating and fertilization are possible, but genetic differences result in a zygote that is unable to develop properly.

Question 21

What is hybrid inviability?

Answer 21

The offspring is a hybrid of the two organisms but they die before birth or if they are born they cannot survive to maturity.

Question 22

What is hybrid infertility?

Answer 22

Hybrid offspring remain healthy and viable but are sterile (they cannot reproduce)

Question 23

What is gradualism?

Answer 23

a slow and continuous process of evolutionary change over long periods, with new species arising gradually from ancestral forms

Question 24

What is punctuated equilibrium?

Answer 24

Describes a process of evolution that suggests very short, rapid periods of change followed by long periods of stability (no change).

Question 25

What is divergence and convergence evolution?

Answer 25

- Divergence: When one single species is placed under selective pressures and evolves to occupy unique niches - Convergent: Occurs when two different species evolve to occupy similar ecological niches in different geographic regions but similar environmental pressures (but no common ancestor)

Question 26

What are the types of mutation?

Answer 26

- Neutral mutations do nothing - Harmful mutations reduce the reproductive success of the organism, Ex. turner’s syndrome - Beneficial mutations produce changes that give the organism an advantage, Ex. drug resistant bacteria

Question 27

What is the importance of genetic variation?

Answer 27

Genetic variation allows for a species to adapt which results in evolution overtime. Often, mutations are the source of genetic variation

Question 28

What impact does mutations have on human health?

Answer 28

Since viruses carry genetic information even though they are not alive and are genetically variable and can change overtime, These mutations can increase the viruses ability to spread which is why every year we try to predict these changes and update vaccines

Question 29

What is selective breeding?

Answer 29

Selective breeding includes domestication which is the changing of members of a species to suit human needs through controlled captive breeding. (ex. domestication of dogs from wolves)

Question 30

How does selective breeding work?

Answer 30

When a trait is found favourable, that plant/organism is chosen to reproduce. This means that the trait is more likely to show up in the next generation

Question 31

What power does artificial selection have?

Answer 31

- Reduces genetic variation because we are choosing one trait over and over again - Overtime they might not be suitable for their environment - Can also produce organisms far beyond the natural variability within the original population - Can make a species vulnerable to disease or extinction

Question 32

What is biogeography?

Answer 32

The scientific study of the geographic distribution of organisms based on both living species and fossils

Question 33

What is a homologous feature?

Answer 33

Similar structures but different functions. Closely related species share homologous features because they shared a common ancestor. Overtime, as species evolved the original structures were modified. Closely related species also share homologous developmental processes and patterns.

Question 34

What are analogous features?

Answer 34

A structure that performs the same function but is not similar in structure (bird wings and insect wings). Analogous features are evolved independently from each other

Question 35

What are vestigial features?

Answer 35

Features that no longer serve the function they do in similar species (Ex. the extra toe pigs have but don’t use or goosebumps in humans). Can be explained as evolutionary baggage

Question 36

What is competition in populations caused by?

Answer 36

Populations are limited in size by their environment and food supply. Populations can't grow indefinitely since there isn’t enough food which leads to competition for survival within species.

Question 37

What is speciation?

Answer 37

- Speciation: the formation of a new species in the course of evolution - If enough adaptation occurs over a period of time, two organisms can become two different species and they will no longer mate with each other

Question 38

What is reproductive isolation?

Answer 38

Reproductive isolation is when organisms are separated from each other and some mechanism is preventing them from mating. Reproductive isolation mechanisms are factors that prevent two populations from interbreeding while in the same region.

Question 39

What is the difference between prezygotic and postzygotic?

Answer 39

- Prezygotic: something that is preventing the organisms from mating with each other - Postzygotic: Organisms that can mate and form a zygote but the offspring either can’t or doesn’t reproduce

Question 40

What is Allopatric speciation?

Answer 40

Formation of a new species through the separation of the species into two geographically isolated populations.

Question 41

What is Sympatric speciation?

Answer 41

Formation of a new species within a large population without the need for geographical separation. Can result from mutation or change in the environment

Question 42

What are some patterns of evolution?

Answer 42

- Closely related species share many homologous features even if they don’t have the same function - Species may have vestigial structures that once served a function in their ancestors - Analogous features have similar functions but different features - Remote islands are inhabited by unique species that are descended from a few individuals who were able to reach the island

Question 43

What is adaptive radiation?

Answer 43

- Occurs when a single species evolved into a number of distinct but closely related species (Ex. the finches) - Occurs when a new variety of resources become available that are not being used by the other species

Question 44

What is coevolution?

Answer 44

- Organisms adapt and evolve with each other - When a species evolutionary success is closely like another species - Ex. predator-prey - Symbiotic relationships start to occur due to this (in some cases, when one species gets wiped out so does the other)

Question 45

What caused extinction?

Answer 45

Changes in the environment and isolation that occurs too quickly for the organism to adapt

Question 46

What is uniformitarianism?

Answer 46

The theory that geological changes are slow and gradual and natural laws have not changed. Earth has been changed by the same processes in the past as it is right now.

Question 47

What is catastrophism?

Answer 47

The theory that the pattern of fossils could be connected to the series of global catastrophes that wiped out most species on earth.

Question 48

What does reading fossils tell us?

Answer 48

the discovery of fossils of unknown organisms, there being no fossils of living species, fossils being buried kilometres below earth's surface, and fossils being found in unexpected locations like desserts. Oldest fossil deposits contain only simple life forms while recent ones have complex organisms similar to the ones already existing.

Question 49

Why are bacteria that exhibit resistance to antibiotics becoming more widespread?

Answer 49

less-resistant strains of bacteria are being killed off by antibiotics

Question 50

Which scientists claimed that life may have evolved from a single source?

Answer 50

Erasmus Darwin