Evolution

Question 1

What is evolution?

Answer 1

The idea that all species are descendants of ancient species that are different from modern day species.

Question 2

Explain the different contributions Hutton, Lyell, Curvier, Lamarack

Answer 2

Hutton: challenged the idea the earth was less than 10,000 years old. Proposed rock formation was gradually formed.
Lyell: popularized and expanded on Hutton’s ideas. Found support rock formations were a slow process.
Curvier: challenged the idea species were fixed. Elephant vs. Mammoth: similar but different species.
Lamarack: hypothesized evolution is a process of adaptation. (Not true but helped Darwin’s theory)

Question 3

Explain Lamarack’s three guiding principles.

Answer 3

1. Use it or lose it
2. Inheritance of acquired characteristics
3. Organisms have a tendency towards perfection.

Question 4

Explain some of the patterns in diversity Darwin noticed during his voyage.

Answer 4

Species vary globally: distantly related species live in similar habitats, had similar characteristics and actions. Some areas had unique species (marsupials only in Australia)
Species vary locally: related animals that lived in different local areas had different features.
Species vary over time: found fossils that were giant versions of animals that exist today.

Question 5

Explain the two points of the origins of species.

Answer 5

1. All species of animals on earth are descended from ancient species.
2. The mechanism that causes species to change over time is called natural selections

Question 6

Explain the three key points of natural selection.

Answer 6

1. The struggle for existence: competition for limited resources. Small percentage of offspring will survive in each generation to reproduce.
2. Variation: differences among members of the same species. Some individuals have variation more suitable for their habitat. These ones survived and therefore reproduces more.
3. Role of the environment: individuals better suited to their environment survived more than others.

Question 7

Explain survival of the fittest.

Answer 7

Fitness - an individual’s ability to survive and reproduce in its specific environment.
Individuals with adaptations that increase their fitness will survive and reproduce more successfully.

Question 8

Explain the different evidence for evolution.

Answer 8

1. Fossil record - transitional fossils show a link between past and present.
2. Geographic distribution - closely related but different species, similar habitats for similar adaptations.
3. Comparative anatomy - certain similarities in structure among species provide clues to evolutionary history.
4. Comparative development - embryos of closely related organisms have similar stages in development.
5. Molecular biology: DNA provides a record of an organisms ancestry.

Question 9

Explain homologous structures, vestigial structures, analogous structures.

Answer 9

Homologous: forelimbs, can have different functions (wings, flippers, running)
Vestigial: remanants of strictures that may have ancestral,y been useful but aren’t any longer.
Analogous: have same function but are anatomically different.

Question 10

Explain the evidence for natural selection.

Answer 10

1. Artificial selection - selective breeding by humans to produce traits we value
2. Changes in beak shape
3. Antibiotic resistance in bacteria

Question 11

What is a gene pool?

Answer 11

Consists of all the alleles in all the individuals that make up a population. Example: sickle cell disease.  a population that has a
higher frequency of the recessive
allele in its gene pool will have a
higher population of individuals
with sickle cell disease

Question 12

What are the two main sources of variation?

Answer 12

1. Mutation due to mistakes in DNA replication

2. Sexual reproduction

Question 13

What is the Hardy-Weinberg criteria that means a species will not evolve if it doesn’t meet it.

Answer 13

1. Random mating
2. Large population
3. No movement in or out of the population
4. No mutations
5. No natural selection

Question 14

What is micro evolution?

Answer 14

Evolution on the smallest scale. A generation to generation change.

Question 15

Explain the five mechanisms of micro evolution.

Answer 15

1. Natural selection
2. Sexual sel3ction (more attractive, more likely to get a mate)
3. Artificial selection
4. Genetic drift (change in the gene pool due to chance, bottleneck effect)
5. Gene flow - exchange of genes in another population.

Question 16

Explain stabilizing, directional and disruptive selection.

Answer 16

Stabilizing - occurs when individuals near the centre of the phenotype range have a higher fitness than individuals at either end of the range
Directional - occurs when individuals at one end of the phenotype range have a higher fitness than individuals in the middle or at the other end of the range
Disruptive - occurs when individuals at the upper
and lower ends of the range have higher fitness than
individuals in the middle. (may lead to different phenotypes
in a population)

Question 17

What is a species?

Answer 17

Two individuals can mate and produce viable offspring.
A set of organisms adapted to a similar set of resources, or niche.
Identical by morphological criteria.
A group whose members are descended from a common ancestor and share a combination of defining traits.

Question 18

PRE-ZYGOTIC

o Behavioural isolation o Temporal isolation o Ecological isolation o Mechanical isolation o Gamete isolation

Answer 18

Behavioural Isolation — capable of breeding but have different courtship rituals
Temporal isolation — species reproduce during different seasons or at different times of day.
Ecological isolation — species occur in the same area but have different habitats and rarely encounter each other.
Mechanical isolation — structural differences between species prevent mating.
Gamete isolation — gametes of one species function poorly with the gametes of another species or the reproductive tract of another species.

Question 19

POST-ZYGOTIC

o Hybrid inviability o Hybrid infertility o Zygotic mortality

Answer 19

hybrid embryos don’t develop properly, hybrid adults do not survive in nature or hybrid adults are sterile or have reduced fertility.

Question 20

Allopatric vs. Sympatric Speciation

Answer 20

Allopatric speciation is when species are separated by physical means. Sympiatric speciation is when they are not separated by physical means but speciation still occurs.

Question 21

Lolilta the Whale being released into the wild—implications

Answer 21

She hasn’t developed the social skills, doesn’t know how to hunt, can’t communicate with the other whales.

Question 22

Discuss the Burgess Shale.

Answer 22

Located in BC. Was discovered by a palaeontologist named Charles Walcott in 1909. Fossils are about 505 million years old. A lot of these fossils were found in complete form, which is rare already, but most of the fossils were soft-bodied. Animals with bones are typically more successfully preserved as fossils.

Question 23

What is Archaeopteryx

Answer 23

A transitional fossil because of its characteristics of both reptiles and dinosaurs.

Question 24

Explain the tuskless elephants.

Answer 24

Due to heavy poaching in many areas in Africa, elephants with tusks were more targeted, and therefore their population dwindled. Now, there are high proportions of tuskless elephants in areas where poaching was common. These elephants then went on to reproduce and create tuskless offspring.

Question 25

Why were dinosaurs so big?

Answer 25

Two theories:
A meteor killed off lots of dinosaurs, leaving the remaining with lots of space to grow m
The meteor caused conditions favourable to plant life, the abundance of food caused the dinosaurs to grow.