Adaption, Variation, Natural Selection Pt.2

Question 1

What are homologous structures?

Answer 1

Similar structural elements that may have a different function

Homologous structures indicate evolutionary relationships among species.

Question 2

What are analogous structures?

Answer 2

Structures that perform similar functions but do not have a common evolutionary origin

Analogous structures arise due to convergent evolution.

Question 3

What are vestigial structures?

Answer 3

Structures present in modern organisms that serve no purpose

Examples include the human appendix and whale pelvis.

Question 4

What did scientists notice about embryos in the 1800s?

Answer 4

Striking similarity between embryos of different species

This observation led to insights about evolutionary relationships.

Question 5

What does ‘ontogeny recapitulates phylogeny’ mean?

Answer 5

An organism shows its evolutionary history through its embryology

This concept suggests that developmental stages reflect evolutionary ancestry.

Question 6

What is the relationship between related organisms and developmental stages?

Answer 6

The more closely related organisms are, the more their developmental stages will resemble each other

This is observed in various species like bats, birds, and dragonflies.

Question 7

What is a significant similarity shared by all organisms?

Answer 7

Similar DNA and proteins

This commonality suggests a shared ancestry among all life forms.

Question 8

What is the significance of genetic similarity between species?

Answer 8

The closer related organisms are, the more similar their DNA sequences

For example, humans and chimpanzees share 98.5% of their DNA.

Question 9

How genetically similar are humans and chimpanzees?

Answer 9

98.5% homologous

This high percentage indicates a close evolutionary relationship.

Question 10

What percentage of genetic similarity do all humans share?

Answer 10

100%

While all humans have the same genes, sequence differences make each person unique.

Question 11

What percentage of genetic similarity do chimpanzees share with humans?

Answer 11

98%

Chimpanzees are the closest living relatives to humans.

Question 12

What percentage of genetic similarity do mice share with humans?

Answer 12

92%

This high similarity highlights the genetic closeness of mammals.

Question 13

What percentage of genetic similarity do fruit flies share with humans?

Answer 13

44%

Research on fruit flies has provided insights into genetic functions applicable to both insects and mammals.

Question 14

What percentage of genetic similarity do yeasts share with humans?

Answer 14

26%

Yeasts have many housekeeping genes similar to those in humans.

Question 15

What is the genetic similarity percentage between thale cress weed and humans?

Answer 15

18%

Despite significant metabolic differences, some similarities exist in housekeeping genes.

Question 16

What is phylogeny?

Answer 16

The evolution of a species or group, especially in reference to lines of descent and relationships among organisms

Phylogenetic trees visually represent these evolutionary relationships.

Question 17

How can evolutionary branching be depicted?

Answer 17

In a tree

Phylogenetic trees illustrate the connections between different species.

Question 18

What is a hypothetical common ancestor?

Answer 18

An ancestral organism from which multiple species have descended

This concept is fundamental to understanding evolutionary biology.

Question 19

What is a character change in phylogenetics?

Answer 19

A change inherited by a species that can indicate evolutionary relationships

Such changes help in constructing phylogenetic trees.

Question 20

What is speciation?

Answer 20

Formation of a new species through natural selection.

Question 21

What are the pathways for generating new species?

Answer 21

• Transformation
• Divergence

Question 22

What is transformation in the context of speciation?

Answer 22

One species gradually changes into another by which it is replaced.

Question 23

What is divergence in speciation?

Answer 23

One or more species arise from a parent species that continues to exist.

Question 24

What is required for speciation to occur?

Answer 24

Barriers that cause a group of individuals of the same species to be isolated from the rest.

Question 25

What are geographical barriers?

Answer 25

Barriers such as rivers and mountains that can divide populations.

Question 26

How do geographical barriers affect populations?

Answer 26

Populations on each side of the barrier will evolve independently.

Question 27

What are biological barriers?

Answer 27

Factors that keep individuals reproductively isolated even when ranges overlap.

Question 28

Give examples of biological barriers.

Answer 28

* Different mating calls * Dances * Pheromones * Habitats * Breeding times/seasons * Mechanical barriers

Question 29

What is the simplified summary of how speciation occurs?

Answer 29

* Population is separated by a physical or behavioural barrier * No longer sharing mutations * Natural selection works on separated groups * Accumulated differences lead to two distinct species.

Question 30

What is reproductive isolation?

Answer 30

Occurs when genetic variation allows individuals to exploit different resources.

Question 31

What is adaptive radiation?

Answer 31

Diversification of a common species into a variety of species, all of which are differently adapted.

Question 32

What is the pace of evolution characterized by slow, steady, linear change over time?

Answer 32

Gradualism ## Footnote Gradualism refers to the theory that evolution occurs slowly and gradually over long periods.

Question 33

What is punctuated equilibrium?

Answer 33

Long periods of equilibrium interrupted by 'rapid' periods of speciation ## Footnote Punctuated equilibrium suggests that species remain relatively unchanged for long periods, with rapid changes occurring during speciation events.

Question 34

What summarizes the evolution by natural selection?

Answer 34

1. Life forms have developed from ancestral species 2. All living things are related by varying degrees 3. All living things on Earth have a common origin 4. Speciation requires random heritable genetic mutations ## Footnote These points outline the fundamental concepts of evolution by natural selection.

Question 35

What is required for speciation?

Answer 35

Random heritable genetic mutations ## Footnote Speciation occurs when these mutations provide a selective advantage, allowing individuals with these traits to survive and reproduce.

Question 36

True or False: All living things on Earth have a common origin.

Answer 36

True ## Footnote This concept is integral to the theory of evolution, indicating a shared ancestry among all life forms.

Question 37

Fill in the blank: __________ requires random heritable genetic mutations.

Answer 37

Speciation ## Footnote Speciation is the process by which new species arise, often facilitated by genetic changes.