Unit 1 Flashcards

Question

What hypothesis did Darwin and Wallace propose in the mid 1800s

Answer 1

That species were modified by natural selection

Answer 2

organisms best suited to their environment survive and reproduce more successfully than other organisms. Thus, over time (perhaps thousands to millions of years) the proportion of organisms with favourable traits increase in a species

Answer 3

Darwin and Wallace proposed their theories at the same time but Darwin’s name is known better after his book ON THE ORIGIN OF SPECIES was published in 1859

Answer 4

It was shaped during his 5 year trip aboard the HMS Beagle to South American and the South Pacific

Answer 5

One example o f his tindings is the finch. In the Galapagos Islands. Darwin collected i species of finch. They had slightly different bills but otherwise were very similar. This implied that they shareda common anscestor, perhaps a few biras that had been blown from South America. He reasoned that one anscestor could evolve into many species over millions of years

Answer 6

Dark and light moths. The genetic variation is inherited Most peppered moths in Manchester were light. They were practically invisible on the tree trunks covered with light lichen. Black moths were very visible and easy prey for birds Light coloured moths survived bc the birds couldn’t see them. They were more adapted than black moths and lived, reproduced, and had offspring.

Answer 7

During the Industrial Revolution, air pollution from burning coal darkened tree trunks. Light moths stood out more and were picked off by birds. Very few light moths were left to reproduce. Black moth population increased bc they were now better adapted.

Answer 8

Pollution control measures increased and trees are becoming lighter so the population of light moths is increasing

Answer 9

•Each species is adapted to the particular local environment. Darwin thought the various species arose from a common anscestral type • According to this theory, a pregnant female, or pair of finches arrived on one of the Gala pagos Islands. • The anscestral type is thought to have beead a sone spaped beak that was adapted for crushing seeds • Finches spread out to different islands. Each group remaned isolated in is own niche. Finches with characteristics that helped them to adapt survived and reproduced. • Gradual changes resulted in the development of new species from the anscestral type.

Answer 10

There are six species of ground living finches. Three of them eat seeds but diff kinds of seeds. The fourth species has a long pointed beak and eats prickly pears. Other two species eat cacti

Answer 11

6 species of tree finch. 1 eats buds &e fruit with a parrot beak. 4 insect. eating species. Another species eats insects & uses a twig to dislodge insects from tree bark.

Answer 12

Evolved from one common ancestor

Answer 13

No. When placed into cuntact wi eachother they do not interbreed

Answer 14

In adaptive radiation, one form of life spreads to a variety of habitats, separates into isolated groups and evolves into dift species over time

Answer 15

1. Descent with Modification 2. Modification by Natural Selection

Answer 16

•States that newer forms appearing in the fossil records are actually the modified descendants of older species. • Also stated that ALL living things descended from one, or a few common anscestors millions to billions of years agos •This theory also accounted for the fact that similar organisms arise in the same geographical location (fig 15-6 pg. 281)

Answer 17

3 points. - Overproduction - Variation - Adaptation

Answer 18

more organisms are born than can ultimately survive. There is competition within the species for food, habitat, survival from being eaten

Answer 19

when organisms are born they are not all the same. There is variation (heritable differences that exist among individuals) that exists in every population (all the individuals of a species that live in an area and are capable of interbreeding) Natural-selection acts on existing variation and it acts on phenotypes (physical traits (ubservable)

Answer 20

the "strong" or "best suited" that are selected by the environment due t o changes in climate, topography, food supply, predators ete) survive and pass these characteristics on to their ottspring and these traits become more common in the population over time - “survival of the fittest” does NOT mean the “strongest” survive, “fit” is a measure of the ability to survive and produce more offspring

Answer 21

“survival of the fittest” does NOT mean the “strongest” survive, “fit” is a measure of the ability to survive and produce more offspring

Answer 22

1. Environment changes thus creating a “need” to change (making it sound voluntary) 2. Development of new ACQUIRED features “in order to survive” or “so one can survive”. Acquired traits arise during the lifetime of an organism and don’t change its genotype. Ex: walking with a limo bc of previous broken leg 3. Newly acquired traits (through use and/or non use) somehow get passed down to offspring 4. New species eventually

Answer 23

1. Environment "screens out" (or SELECTS) features contributing to survival, and tends to eliminate others 2. Variations of inheritable features which already normally exist organisms are all a little bit afferent 3. Those with traits which help survival tend to survive and have more offspring, who inherit those traits. 4. New species, eventually

Answer 24

Ex. albino birds not surviving in wild because they stand out and. are easier for predators to see, also more prone to cancers (skin, eye, etc.)

Answer 25

Fossils formed and were covered with sand or mud. Layers formed and turned into sedimentary rock. Some event such as the erosion of the Grand canyon or the building of a highway exposed the fossils again.

Answer 26

The use of potassium and uranium, mass and half life, or Carbon 14

Answer 27

Potassium has a half-life of 1.3 billion years. This means that it takes 1.3 billion years for half its mass to disintegrate. Potassium can be used to determine the age of the oldest fossils is 3.5 billion years old

Answer 28

Carbon 1 4 can b e used to age the actual fossil. Carbon 14 decays into Nitrogen 14 which has a half life of 5730 years. It is the ratio of carbon to nitrogen that indicates the age of the fossil. For ex. if the measured abundance of C14 and NI4 in bone are equal, one half life has passed and the bone is 5730 years old (Amt equal to the half life of C14). If there is 3 times less C14 than N14 in the bone, 2 half-lives have passed and the sample is 11,460 years old.

Answer 29

proposed by Wegener, a German scientist in 1912.

Answer 30

He suggested that the present continents had once been joined in a supercontinent he called Pangaea. He thought that these big land masses were floating apart over the Earth's hot liquid interior.

Answer 31

His hypothesis was not well accepted at the time but is now part of a broader theory called PLATE TECTONICS.

Answer 32

molten rock from the Earth's interior forces its way through the ocean floor, cools and begins to move away from this ridge. Where it meets the land it is forced beneath the continent. This is what forms mountains, volcanoes and earthquakes.

Answer 33

areas where the plates meet and where 90 % of earthquakes occur.

Answer 34

• Forms new islands such as the Galapogos which create new environments for new species. • As Pangaea broke up it isolated species into groups. This is how small pockets of strange species like marsupials and placental mammals are thought to have been separated. Marsupials are found only in Australia and South America which are thought to have been joined together as Pangaea.

Answer 35

Variation in a species can be caused by mutation, migration or nonrandom mating.

Answer 36

A species is a population of organisms that can successfully interbreed but cannot breed with other groups

Answer 37

Speciation begins with ISOLATION. In isolation two parts of a formerly interbreeding population stop interbreeding.

Answer 38

Geographic isolation Reproductive isolation

Answer 39

physical separation of members of a population. This could be caused by continental drift or a deep canyon for example. Once the subpopulations become isolated gene flow between them stops. Natural selection causes the two groups to become less alike. Eventually they are incompatible for mating.

Answer 40

results from barriers to successful breeding in groups in the same area. If the two extremes of a trait are selected for, the organisms may become so different that they are unable to mate. An example of this could be a toy poodle and a Newfoundland dog. The extreme sizes may cause the dog populations to become separate species.

Answer 41

exists when timing prevents reproduction between populations. To reduce competition, courtship signs or reproductive periods may change. Ex: Monterey and Bishop pine have different pollination periods N p 326

Answer 42

- isolation caused by different courtship or mating behaviors. Ex: firefly light flashing patterns are specific to each species. N p 325

Answer 43

The elimination of a species from Earth is called extinction.

Answer 44

Extinction often occurs when a species as a whole is unable to adapt to a change in its environment

Answer 45

1. Gradualism 2. Punctuated Equilibrium

Answer 46

a slow smooth process that occurs over many generations and millions of years. N p 283 & 285

Answer 47

occurs much more quickly (100-1000s of years.) N page 331

Answer 48

• Any of the developmental control genes that define the head-to tail pattern of development in animal embryos. (Homeotic genes control early development in animals) • The first hox gene was discovered in Drosophila (fruit flies.) Mutation in this gene leads to the formation of a normal structure or organ in place of another at an abnormal site. i.e. mutation in the antennapedia hox gene of Drosophila leads to the formation of leg in place of antenna from its head.

Answer 49

Epigenetics literally means "above" or "on top of" genetics.

Answer 50

It refers to external modifications to DNA that turn genes "on" or "off." These modifications do not change the DNA sequence, but instead, they affect how cells "read" genes.

Answer 51

Epigenetics refers to the idea that environmental factors can change how a DNA sequence is expressed.

Answer 52

This is somewhat similar to Lamarck's ideas that characteristics acquired over a lifetime DO or MAY affect your DNA.