Evolution

Question 1

What is evolution?

Answer 1

Evolution is the change in allele frequencies in a population over time.

Question 2

What are the three main arguments for evolution?

Answer 2

1. Species vary locally
2. Species vary globally
3. Species vary through time

Question 3

What is biogeography?

Answer 3

The study of how species are distributed across the planet and how geography affects evolution.

Question 4

What is comparative morphology?

Answer 4

The study of structural similarities and differences in organisms to determine evolutionary relationships.

Question 5

What are homologous structures?

Answer 5

Structures that share a common origin but may have different functions (e.g., human arm and whale flipper).

Question 6

What are analogous structures?

Answer 6

Structures with similar functions but different evolutionary origins (e.g., bird wings vs. butterfly wings).

Question 7

What are vestigial structures?

Answer 7

Body parts that have lost their original function through evolution (e.g., human tailbone).

Question 8

Why is the fossil record incomplete?

Answer 8

Many organisms do not fossilize due to decay, lack of sedimentation, or destruction over time.

Question 9

What counts as a fossil?

Answer 9

Any preserved remains, impressions, or traces of ancient organisms.

Question 10

How do fossils help us understand evolution?

Answer 10

They provide physical evidence of past life forms and show changes over time.

Question 11

What was the significance of Darwin’s trip on the Beagle?

Answer 11

It allowed him to observe species variations, leading to his theory of natural selection.

Question 12

Why are the Galápagos Islands important in evolution?

Answer 12

They were home to unique species that helped Darwin develop his ideas on adaptation.

Question 13

What did Darwin’s finches demonstrate?

Answer 13

Adaptive radiation—different beak shapes evolved to match available food sources.

Question 14

How does natural selection work?

Answer 14

It leads to changes in allele frequencies as advantageous traits become more common.

Question 15

Who else contributed to evolutionary theory?

Answer 15

Alfred Russel Wallace independently conceived the theory of natural selection.

Question 16

What is radiometric dating?

Answer 16

A method that uses radioactive isotopes to determine the age of fossils and rocks.

Question 17

What is half-life?

Answer 17

The time it takes for half of a radioactive isotope to decay.

Question 18

What was Pangea?

Answer 18

A supercontinent that existed before plate tectonic movements separated landmasses.

Question 19

What is plate tectonic theory?

Answer 19

The idea that Earth’s crust is divided into plates that move, affecting evolution and species distribution.

Question 20

How do mutations contribute to evolution?

Answer 20

They introduce new alleles into a population

Question 21

What are the three types of mutations?

Answer 21

Beneficial, harmful, and neutral

Question 22

What is immigration in evolutionary terms?

Answer 22

Movement of individuals into a population, introducing new alleles.

Question 23

What is emigration?

Answer 23

Movement of individuals out of a population, reducing genetic diversity.

Question 24

What is genetic equilibrium?

Answer 24

A state where allele frequencies in a population remain constant over generations.

Question 25

What is random mating?

Answer 25

When individuals pair by chance rather than by selective traits.

Question 26

What is sexual selection?

Answer 26

When certain traits increase reproductive success, leading to non-random mating.

Question 27

What is directional selection?

Answer 27

Favors one extreme trait (e.g., giraffes with longer necks).

Question 28

What is allopatric speciation?

Answer 28

New species form due to geographic isolation.

Question 29

What is the founder effect?

Answer 29

A small group starts a new population with limited genetic variation.

Question 30

What is the bottleneck effect?

Answer 30

A sharp population reduction due to an event, reducing genetic diversity.

Question 31

What are postzygotic isolating mechanisms?

Answer 31

Barriers that prevent viable, fertile offspring

Question 32

What defines a species?

Answer 32

A group of organisms that can interbreed and produce fertile offspring.

Question 33

What is speciation?

Answer 33

The formation of new species when populations become reproductively isolated.

Question 34

How do geographic barriers affect speciation?

Answer 34

They prevent gene flow, leading to genetic divergence.

Question 35

What is Linnaean taxonomy?

Answer 35

A classification system based on hierarchical categories (Kingdom, Phylum, etc.).

Question 36

What is the phylogenetic system of classification?

Answer 36

A system based on evolutionary relationships and common ancestry.

Question 37

What are master genes?

Answer 37

Genes that control major developmental processes (e.g., Hox genes in limb formation).

Question 38

What is the Big Bang Theory?

Answer 38

The scientific theory explaining the origin of the universe.

Question 39

How did oxygen levels change early Earth?

Answer 39

Early Earth had little oxygen; photosynthetic organisms later increased atmospheric oxygen.

Question 40

How did amino acids develop on early Earth?

Answer 40

Possibly through chemical reactions in Earth’s primitive atmosphere or from meteorites.

Question 41

What were the first cells like?

Answer 41

Anaerobic (did not need oxygen); later evolved into aerobic cells as oxygen increased.

Question 42

How did early photosynthesis impact evolution?

Answer 42

It produced oxygen, allowing for aerobic respiration and more complex life forms.

Question 43

What is the endosymbiotic theory?

Answer 43

The idea that mitochondria and chloroplasts originated as symbiotic bacteria.

Question 44

What did the Miller-Urey experiment demonstrate?

Answer 44

That organic molecules (amino acids) could form under early Earth conditions.

Question 45

What is the Hardy-Weinberg Principle?

Answer 45

A mathematical model predicting allele frequencies in a non-evolving population.

Question 46

What is the Hardy-Weinberg equation?

Answer 46

p² + 2pq + q² = 1, where p and q represent allele frequencies.

Question 47

What are the advantages of asexual reproduction?

Answer 47

• Fast reproduction • Requires only one parent • No need for complex mating behaviors

Question 48

How does sexual reproduction increase genetic variation?

Answer 48

• Crossing over during meiosis • Independent assortment of chromosomes • Random fertilization

Question 49

What is the difference between asexual and sexual reproduction?

Answer 49

• Asexual: One parent, identical offspring. • Sexual: Two parents, genetic variation.

Question 50

Explain two advantages of asexual reproduction.

Answer 50

• Fast reproduction – No mate needed. • Energy-efficient – Saves resources.

Question 51

Explain how sexual reproduction creates genetic variability.

Answer 51

Crossing over, independent assortment, and random fertilization shuffle genes.

Question 52

Two prezygotic mechanisms?

Answer 52

• Temporal isolation – Different mating times. • Behavioral isolation – Different courtship behaviors.

Question 53

Mutation

Answer 53

Source of new alleles

Question 54

Crossing over at Meiosis 1

Answer 54

Introduces new combinations of alleles into chromosomes

Question 55

Independent Assortment at Meiosis 1

Answer 55

Mixes maternal and paternal chromosomes

Question 56

Fertilization

Answer 56

Combines alleles from two parents

Question 57

Change in chromosome number or structure

Answer 57

Transposition, duplication, or loss of chromosomes

Question 58

Order

Answer 58

Species- Genus- Family- Order- Class- Phylum- Kingdom- Domain SGFOCPKD

Question 59

Master Genes

Answer 59

• Hox genes: Control body plan and segment identity. • Dlx genes: Regulate limb and skull development.