evolution 🙊

what is a species?

a group of living organisms that can breed with one another and produce fertile offspring

name the four points in the theory of evolution (4)

1. every species produces more offspring than can survive due to limited resources

2. overproduction leads to competition between the members of a species for the limited resources

3. there is an inherited variation among the members of a species (caused by genetic differences)

4. individuals who are poorly adapted to their environments are unlikely to survive long enough to produce offspring

what is overproduction?

when a species produces more offspring than can survive ep. because of limited food

1. what happens to well adapted individuals?

2. what happens to the poorly adapted individuals?

3. what is this process also known as?

1. they survive long enough to reproduce, passing on the favourable traits, which can eventually, over many years cause major changes in the traits of species

2. they die before they are able to reproduce, preventing the poorly adapted genes from passing on

3. natural selection

what is natural selection?

the process by which nature selects favourable traits, individuals with favourable traits live long enough to reproduce, those with unfavourable traits do not

what is a fossil?

the preserved remains of living organisms that lived thousands to millions of years ago

what are fossils found in?

in sedimentary rock

what does a phylogenetic tree show?

how species are related to each other through evolution

what does __ indicate on a phylogenetic tree

a) a branching point

b) the y axis

c) the top

d) the bottom

e) each line

a) a speciation point/speciation event

b) time

c) present

d) past

e) a species

what are the three main steps of a speciation event? (3)

geographical isolation, divergence, reproductive isolation

how does a speciation event occur? (4)

1. members of a species can mate with each other to produce fertile offspring

2. geographical isolation occurs, the species is separated into two separate populations

3. over many generations, the 2 different populations become increasingly different from one another as they evolve to their environments (divergence)

4. reproductive isolation occurs, meaning that the two groups can no longer mate and produce fertile offspring

give an example of..?

a) how geographical isolation could occur

b) divergence

c) the hard parts of fossils that don’t decay (3)

d) types of sediment (2)

e) types of sedimentary rock (3)

a) individuals make their way to an island far from the mainland

b) each population evolves to camouflage better in their environments

c) bone, shell, teeth

d) sand, silt

e) limestone, sandstone, shale

what is fossilisation?

the process by which the minerals in water replace the minerals in bone

how do fossils form in sedimentary rock? (5)

1. an animal dies and falls to the bottom of a lake or ocean

2. soft parts of the animal decay, leaving the hard parts

3. a layer of sediment covers the hard part of the organism

4. over 1000s of years, sediment builds up. the minerals in the bone are replaced with the minerals in the water. pressure from the upper sediment layers compresses the lower layers into sed. rock

5. the land is lifted by tectonic plate movement, and a river erodes the sed. rock to reveal the fossil

what is shown in this image?

a thin layer of silt covers the hard parts of the fossil

what is shown in this image?

tectonic plates shift, raising the land and the fossil is revealed after sed. rock is eroded by a river

which are these two species are more closely related and why?

B and C, because they have the most recent common ancestor

are these phylogenetic trees different or the same?

the same

all life on earth is _. therefore, all _ can be placed on a _ tree. (3)

related, species, phylogenetic tree

how can you figure out if species are related to each other?

by comparing which physical traits they share

how many species of _ are there?

a) mosses

b) conifers

c) flowering plants

d) ferns

a) ~12000

b) ~600

c) ~300000

d) ~10000

draw a phylogenetic tree based on this chart

what are some of the organisms darwin noticed in the galapagos? (3)

blue footed boobies, long necked giant tortoises and marine iguanas

what are some characteristics evolved by the iguanas that help them in their environment? (3)

feed on algae in the ocean, partially webbed feet and flat tail

what is one of darwin’s most important contributions?

the scientific explanation for the ways organisms are suited to their environment

which two major factors caused humanity to believe that species were perfect and unchanging? (2)

the book of genesis, the views of the greek philosopher aristotle

how..?

a) old was the earth believed to be before significant scientific advancements were made?

b) is the long necked giant tortoise referred to in spanish?

c) did darwin spend his time as a young boy (4)

a) 6000 years old

b) galapagos

c) reading nature books, fishing, hunting, collecting insects

what did the study of fossils in the mid 1700s reveal?

fossils that differed from the living organisms at the time

what was jean baptiste lamarck’s theory of evolution and why was it wrong?

lamarck correctly believed that fossils evolved into the living organisms he knew, but incorrectly assumed that it was due to an organism intentionally changing its traits and passing on the changed gene

what is jean baptiste lamarck’s theory known as?

inheritance of acquired characteristics

charles darwin:

a) was born in what year

b) was uninterested in medicine because

c) attended which university

d) intended to become

e) sailed on the HMS beagle for how many years

f) spent time on the galapagos islands, found in which ocean?

a) 1809

b) he found it boring, and found surgery horrifying

c) cambridge university

d) a clergyman

e) 5

f) the pacific ocean

after graduation, darwin’s _ professor referred him to the captain of the _.

botany, HMS beagle

what was the purpose of the HMS beagle’s voyage?

to chart the little known south american coast

darwin departed on the HMS beagle in _ at the age of _

december 1831, 22

how did darwin spend his time while the crew were mapping?

he spent time onshore, collecting many different organisms and fossils

which important observations did darwin make while onshore? (3)

1. the unique adaptations of organisms in different remote places

2. that fossils found in south america were more similar to the current organisms in south america than fossils in other continents

3. species on different galapagos islands and mainland were similar but not the same to each other

how did charles lyell’s principles of geology influence darwin?

a combination of witnessing and earthquake and lyell’s book helped darwin to realize that natural forces had and continued to change the earth’s surface

what caused marine snail fossils to be found on the mountaintops in the andes?

earthquakes

what did darwin do once he returned to great britain?

darwin analyzed and discussed his collections, and by the early 1840s, he had produced a long essay describing the theory of evolution which he decided to delay publishing it due to fear of society’s reaction

who was alfred wallace?

a british naturalist who compiled a theory of evolution in the 1850s that was nearly identical to darwin’s

how was darwin’s work eventually published?

- colleagues of darwin presented wallace and darwin’s work to the scientific community

when was..?

a) darwin’s essay presented to the scientific community?

b) on the origin of species by means of natural selection published?

a) 1858

b) 1859

explain “descent with modifications” (2)

- darwin’s theory that present day species arose from a succession of ancestors

- as the descendants spread over millions of years, they began to adapt to their specific ways of life

who wrote on the origin of species?

charles darwin

what is artificial selection? provide an example

a process used by humans to modify species by selecting and breeding individuals to produce certain traits. for example, animals bred as livestock are extremely different from their wild ancestors.

what two observations did darwin make about a process similar to aritificial selection in nature? what conclusions did he draw from this? (4)

observations

1. the members of a population have variations in traits, and most traits are inherited

2. all species are able to produce more offspring than can be supported by the environment

conclusions

1. well adapted individuals tend to produce more offspring than other individuals

2. this causes favourable traits to accumulate in a population

1. who was thomas malthus?

2. when did he publish his essay?

3. what conclusion did he come to in his essay?

4. provide 3 examples of human suffering

1. an economist who wrote an essay on human population

2. 1798

3. much of human suffering was a result of population increasing faster than the environment could handle

4. famine, war and disease

what is the difference between natural selection and artificial selection?

artificial selection entails humans choosing desirable traits by breeding organisms that possess them. natural selection is similar, however the environment “chooses” the traits best suited for survival, and the well adapted individuals survive long enough to reproduce

what is the essence of natural selection?

unequal reproduction

what are the 3 key points of evolution by natural selection? (3)

1. individuals do not evolve in one lifetime

2. only heritable traits are affected by natural selection

3. evolution is not goal directed (does not lead to perfect organisms), and natural selection results from conditions of specific areas at specific times

what is extinction? what can lead to extinction?

the loss of a species, major environmental changes

a) which scientists worked with birds in the galápagos Islands?

b) over how long did their research span?

c) which birds did they study?

d) what did they discover?

a) peter and rosemary grant

b) 20 years

c) finches

d) during dry years, the birds with larger beaks did better, during wet years, birds with smaller beaks did better (aka natural selection)

which historical figure(s)…?

a) wrote on the origin of species

b) had the theory “inheritance of acquired characteristics”

c) came to the same conclusions as darwin in the 1850s

d) wrote principles of geology

e) wrote an essay about human population in 1798

f) researched finches in the galapagos

a) charles darwin

b) jean baptiste lamarck

c) alfred wallace

d) charles lyell

e) thomas malthus

f) rosemary and peter grant

how does natural selection render some pesticides useless?

each new pesticide introduced kills most, but not all of its targets, some of which have genetic resistance. the rest of the species is killed, and the only insects producing offspring are immune to the pesticide, rendering it useless as more and more insects are born resistant

what 3 points can we learn about natural selection based on the example of bugs and pesticide?

1. natural selection is an editing process, not a creative mechanism

2. natural selection is dependant on time and place

3. significant evolutionary change can occur over a short time

what are vestigial structures? (+1 example)

a structure found in a modern species that has no function, hind leg bones in a whale

how do vestigial structures come to be?

the structure had a function when it first evolved however the function was lost through evolution

define selection

process by which traits are selected for or against and become more abundant

1. what are the criteria for:

a) natural selection (3)

b) artificial selection (2)

2. why is the 3rd part of the criteria so important?

1.

a) variation in population, traits must be heritable, environment limits population

b) variation in population, traits must be heritable

2. if the environment is not limiting population (and therefore causing adaptation), then something else must (humans)