2. Descent with Modification (Evolution)

Question 1

What is Adaptation?

Answer 1

a heritable trait that increases the survival and reproduction of an individual in a particular environment compared to individuals without that trait

Question 2

What were Darwins’ Two Main Ideas?

Answer 2

1. Descent with modification (or evolution) explains life’s unity and diversity
2. Natural selection is a cause of adaptive evolution

Question 3

What were Darwins’ Two Main Ideas?

Answer 3

1. Descent with modification (or evolution) explains life’s unity and diversity
2. Natural selection is a cause of adaptive evolution

Question 4

What are the 3 Types of adaptations that exist to enable species to survive?

Answer 4

1. Structural (Physical Features)
2. Behavioural (Learned or Inherited Actions)
3. Physiological (Internal and Cellular Processes)

Question 5

What are some examples of Structural Adaptations? (4)

Answer 5

Ex. 1- Penguins have blubber to protect themselves from freezing temperatures

Ex. 2 - Carnivores have sharp canines to kill and tear meat

Ex. 3 - Giraffes have long necks that allow them to browse leaves off the tops of grassland trees, helping them avoid food competition from other herbivores

Ex. 4 - Chameleons use camouflage to evade a predator

Question 6

What are some examples of Behavioral Adaptations? (4)

Answer 6

Ex. 1 - Bears hibernate in winter to escape cold
temperatures and preserve energy

Ex. 2 - Porcupines curl up into a ball when threatened

Ex. 3 - Fish swim in schools for protection

Ex. 4 Geese fly south in the fall to allow them to stay warm and find food during winter

Question 7

What are some examples of Physiological Adaptations? (2)

Answer 7

Ex. 1 -Snakes produce poisonous venom to ward off predators and capture prey

Ex. 2 - Pesticide and antibiotic resistance

Question 8

What 5 Observations Did Darwin Make?

Answer 8

OBSERVATION #1:
For any species, population sizes would increase exponentially

OBSERVATION #2:
Populations tend to be stable in size

OBSERVATION #3:
Resources are limited

OBSERVATION #4:
Members of a population vary extensively in their characteristics

OBSERVATION #5:
Much of this variation is heritable

Question 9

What 3 Inferences Did Darwin Make?

Answer 9

INFERENCE #1:
Production of more individuals than the environment can support leads to a struggle for existence

INFERENCE #2:
Survival depends in part on inherited traits.
Individuals with traits that give a high probability of surviving and reproducing are likely to leave more offspring

INFERENCE #3:
This unequal ability of individuals to survive and
reproduce will lead to a gradual change in a population, with favourable characteristics being more common

Question 10

Evolution by natural selection occurs when…
(2)

Answer 10

1. heritable phenotypic variation in the population leads to ….
2. differential reproductive success - the unequal ability of individuals to survive and reproduce

Question 11

What is a Phenotype?

Answer 11

– phenotype refers to an organism’s observable characteristics or traits, including its
(i) physical form and structure,
(ii) developmental properties,
(iii) biochemical and physiological properties, as well as
(iv) behaviour

Question 12

What is Biological Fitness?
(3)

Answer 12

the ability of an individual:
1. to survive to reproductive age,
2. find a mate,
3. produce live, fertile offspring

(relative to that ability in other individuals in the population)

Question 13

What does natural selection NOT do? (2)

Answer 13

Natural selection DOES NOT create new traits, but edits or selects traits already present in a population

Note, that individuals DO NOT evolve; populations evolve over time

Question 14

What is Artificial Selection?
(4)

Answer 14

The offspring of each generation vary (the differences may be so small that only trained breeders can detect them)

– Those that are more like what the breeder wants are selected for further breeding; the rest aren’t allowed to breed

– This is repeated

– Eventually, the small differences add up to a large change in the breed

Question 15

What is a Fossil?

Answer 15

A fossil is the preserved remains or traces of an organism that lived in the past

Question 16

What are the 6 most often cited types of fossils?
(MCCPTT)

Answer 16

1. Molds
2. Casts
3. Permineralized Fossils,
4. Carbon film (compression) fossils,
5. Trace fossils
6. True-form (intact) fossils

Question 17

What is a Mold?

Answer 17

A mold is formed when an organism decays completely but leaves behind a hollow physical impression of itself

Question 18

What is a Cast?

Answer 18

A cast forms when minerals and sediment deposit into a mold and hardens over time, resulting in a three-dimensional physical replica of the hard structures of the organism

Question 19

What is a Permineralized Fossils?

Answer 19

Permineralized fossils form as organisms decompose slowly, which allows dissolved minerals to gradually infiltrate the interior of cells and harden into stone

Question 20

What is True-Form Fossils?

Answer 20

True-form fossils preserve the entire natural form of the organism

Include entrapment of organisms in amber/ice/tar, as well as mummification
– Soft issues remain entirely intact

Question 21

What are Carbon film fossils?

Answer 21

• Carbon film fossils are formed from the carbon residue of the soft-bodied organism that has been buried in sediment

– Eventually, all materials that make up the body of a dead organism break down from heat and immense weight of overlying layers of sediment, leaving nothing but a thin film or residue of carbon (forms shape of body outline)

– Usually black, dark brown or light brown in colour, depending on the type of rock they are pressed upon

Question 22

What are Trace Fossils?

Answer 22

Trace fossils provide indirect evidence of life

– Show evidence of organism activity

– Include footprints/trackways, tooth marks, coprolites (fossilized feces), burrows,
nests and gastroliths (small stones swallowed by a bird, reptile, or fish, to aid in
digestion by breaking up food)

Question 23

What is Habitat Bias?

Answer 23

• Organisms that live where sediment is actively being deposited (e.g., beaches, mudflats, swamps) are more likely to fossilize than are organisms in other habitats
• In these habitats, burrowing organisms are more likely to fossilized compared to organisms living above ground

Question 24

What is Taxonomic and Tissue bias?

Answer 24

• Some organisms (e.g., those with hard parts such as bones or shells) are more likely to decay slowly and leave fossil evidence compared to soft-bodied organisms
• Tissues with a tough outer coat that resists
  decay (e.g., pollen) fossilize more readily

Question 25

What is Temporal bias?

Answer 25

• More recent fossils are more common than ancient fossils
• Older fossils usually occur in sedimentary rock layers deep below newer layers
• These fossils are vulnerable to crushing, heating, melting, and distortion by various chemical and physical processes
• Also, older fossils are more likely to be pushed further into the Earth’s interior by the sliding and collision of tectonic plates

Question 26

What is Abundance Bias?

Answer 26

Organisms that are abundant, widespread, and present for a long time leave evidence much more often than do species that are rare, local, or ephemeral (lasting for a very short time)

Question 27

What are Homologous Structures?
(Homology)

Answer 27

• homologous structures are body parts that share a common ancestor, but may not necessarily perform the same function

Example:
– Forelimb bones in a human arm, horse leg, seal flipper and bat/bird wing

Question 28

What is Divergent Evolution?

Answer 28

a process in which a trait held by a common ancestor evolves into different variations over time

Question 29

What are Analogous Structures?
(Homoplasy)
What are some examples?

Answer 29

body parts that perform the same function, but have a different evolutionary history
(so the similarity in function NOT resulting from common ancestry)

Examples:
– Walking limbs of insects and vertebrates
– Wings of birds and bats look similar in the structure though they evolved independently
– Cranium of vertebrates and exoskeleton head of insects
– Eye of octopus and eyes in humans
– Arctic fox and ptarmigan (a bird) both under seasonal changes of colour from dark to snowy white

Question 30

What is Convergent evolution?

Answer 30

Convergent evolution is the process in which species that are not closely related to each other independently evolve similar kinds of traits

Question 31

True or False:
Forelimb bones of humans, dogs, birds and whales represent homologous structures, which were developed through convergent evolution.

Answer 31

False
Forelimb bones of humans, dogs, birds and whales represent homologous structures, which were developed through DIVERGENT evolution.

Question 32

Answer 32

D. population

Question 33

Answer 33

Question 34

Analogous Structures

Answer 34

Question 35

Homologous Structures

Answer 35

Question 36

Answer 36

Question 37

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Question 38

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Question 39

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Question 40

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Question 41

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Question 42

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Question 43

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Question 44

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Question 45

Answer 45