lectrure 3- evidence of evolution

Question 1

what are the 2 definitions of theory regarding science?

Answer 1

Theory (1): A hypothesis propose as an explanation; hence a speculation, conjecture; an idea or set of ideas about something; and individual view or notion.

Theory (2): A scheme or system of ideas or statements held as an explanation or accounts of a group or facts or phenomena;a hypothesis that has been confirmed or established by observation or experiments and is propounded or accepted as accounting for the known facts; a statement of what are held the general laws, principle, or causes of something known as observed

Question 2

what is a theory in science? and what are some theories?

Answer 2

“A hypothesis that has been confirmed or established by observation or experiments and is propounded or accepted as accounting for the known facts (…)”
Heliocentric theory
Gravitational theory (Newton’s Law of Gravity)
Big Bang Theory
Cell theory
Theory of plate tectonics
Theory of Evolution

Question 3

define domestication

Answer 3

Domestication refers to the process by which wild animals or plants are selectively bred and managed by humans for specific purposes, leading to changes in their genetics, behavior, and morphology. It involves the adaptation of wild species to live and reproduce in human-controlled environments, such as farms, households, or other managed settings. Domestication typically results in traits that are desirable to humans, such as increased docility, productivity, or nutritional value.

Question 4

define artificial selection

Answer 4

Artificial selection, also known as selective breeding or human-directed evolution, is a process by which humans intentionally select and breed organisms with desired traits to produce offspring with those same traits. This process mimics the natural selection mechanism observed in the wild but is directed by human preferences or goals rather than natural environmental pressures

Question 5

who breeds in natural selection?

Answer 5

In natural selection you don’t need a breeder, you don’t need a selector, survival will do it for you

Question 6

what is macro evolution?

Answer 6

It refers to larger changes over a long-time scale.

Question 7

what is the path to macro evolution showing us for certain fish?

Answer 7

*That fishing rod has been shaped by selection by the eyes of generations of prey fish
*The ones that look most like wriggling worms, were most successful in luring prey

Question 8

what does survival determine for natural selection?

Answer 8

Survival is all it takes to determine the non-random survival of genes that made the desirable characteristic

As the generations go by, the number of genes that are successful in building bodies that are good at surviving, are the ones that we see in gene pools in species all over the world.

Question 9

what are some different forms of evidence for evolution?

Answer 9

Anatomy: Species may share similar physical features because the feature was present in a common ancestor

Fossils: They document the existence of now-extinct past species that are related to present-day species

Natural history: Traits present in organisms can be understood only in view of their evolutionary path

Embryology: Traits present in organisms can be understood only in view of their evolutionary path

Biogeography: The global distribution of organisms reflects evolution and geological change

Question 10

how does anatomy relate to proof of evolution?

Answer 10

Organisms often look similar in their morphology

Question 11

what is homology? what does it show?

Answer 11

the relatedness of life forms

two traits that have descended from a common ancestral character
such as the wings of a bat, arms of a human, legs of a cheetah or fins of a what having the same bones

Question 12

what is homology and analogy?

Answer 12

Homology= the relationship of any two traits that have descended from a common ancestral trait

Analogy= The relationship of any two traits that have descended from “unrelated” ancestors through convergent evolution

Homologous structures provide evidence for common ancestry

Question 13

what is a fossil? and what are the different types?

Answer 13

A fossil is the preserved remains of a once-living organism.

Petrified Fossils
Molds and Casts
Carbon Films
Trace Fossils
Preserved Remains

Question 14

what do Fossil records show us?

Answer 14

Fossils in older layers are more primitive than those in the upper layers
*Most recent fossils more resemble extant species
*Species change over time
*Transitional forms in major groups *Variation within each species
*Cases of imperfect adaptation

Question 15

what is the Principle of superposition

Answer 15

These early geologists simply ordered the different layers of rocks that they found

Deeper layers must have been laid down before the shallower ones

Use fossils to cross-correlate different locations

Question 16

how do we determine a fossil’s age?

Answer 16

Fossils are generally only found in sedimentary rocks

We can calculate the date of formation of the igneous rock, using radioactive isotopes decay

Question 17

what are the half-lives of important elements?

Answer 17

Element Half-life
Uranium-4.5 Billion years
Californium- 800 years
neptunium- 1hour
Plutonium- 5 hours
Americium- 25 minutes
Nobelium- 3 seconds
Carbon- 5730 years
Carbon-740 milliseconds

Question 18

how old is the planet?

Answer 18

The planet is 4.6 billion years old

Question 19

order the different periods of evolution

Answer 19

1- archean
2- proterozoic
3- paleozoic
4- Mesozoic
5- Cenozoic (with humans)

Question 20

what is the missing link of fossil evolution?

Answer 20

The concept of a “missing link” in fossil evolution refers to a hypothetical transitional fossil that would fill a perceived gap in the fossil record between two different species or lineages. It’s important to note that this term is somewhat outdated and can be misleading, as it implies that there is a single fossil that is crucial for understanding evolutionary relationships. In reality, the fossil record is complex and incomplete, and our understanding of evolutionary relationships is based on a large body of evidence rather than a single fossil.

In paleontology and evolutionary biology, scientists use the term “transitional fossil” instead of “missing link.” Transitional fossils are fossils of organisms that display traits that are intermediate between those of their presumed ancestors and descendants. They provide valuable evidence for evolutionary transitions and the gradual change of species over time.

While there are certainly gaps in the fossil record, scientists have discovered numerous transitional fossils that provide insight into various evolutionary transitions, such as the evolution of whales from land-dwelling ancestors, the evolution of birds from theropod dinosaurs, and the transition from fish to tetrapods (four-legged vertebrates).

It’s also worth noting that our understanding of evolution is not solely based on the fossil record. Other lines of evidence, such as comparative anatomy, embryology, genetics, and biogeography, contribute to our understanding of evolutionary relationships and processes. Overall, while there may not be a single “missing link” fossil, the cumulative evidence from multiple sources allows scientists to reconstruct the history of life on Earth and understand how different species are related to one another

Question 21

what does Evidence from fossil record provide?

Answer 21

The fossil record provides valuable evidence for understanding the history of life on Earth and the processes of evolution. Here are some key contributions of the fossil record:

Documentation of Extinct Species: Fossils provide direct evidence of organisms that lived in the past but are now extinct. By studying these fossils, scientists can reconstruct the diversity of life forms that have inhabited the Earth throughout its history.

Transitional Forms: Fossils often preserve intermediate or transitional forms between different groups of organisms. These transitional fossils provide evidence for evolutionary transitions, such as the evolution of whales from land mammals, the evolution of birds from theropod dinosaurs, and the transition from fish to tetrapods (four-legged vertebrates).

Chronological Sequence: Fossils are dated based on the layers of rock in which they are found, allowing scientists to establish a chronological sequence of life forms over time. This chronological sequence helps researchers understand the timing and pace of evolutionary events and the order in which different groups of organisms appeared and diversified.

Biogeographic Patterns: Fossils found in different regions of the world provide information about past geographic distributions of species and changes in Earth’s continents and environments over time. This evidence helps scientists reconstruct past environments and understand how organisms have migrated and adapted to changing conditions.

Evidence of Extinction Events: Mass extinctions, such as the one that marked the end of the Cretaceous period and the extinction of non-avian dinosaurs, are documented in the fossil record. Studying these extinction events can provide insights into their causes and consequences and help predict future patterns of extinction in response to environmental changes.

Evolutionary Trends: Fossils reveal patterns of evolutionary change over long periods of time, such as trends in body size, shape, and complexity. By studying these trends, scientists can infer the processes driving evolutionary change and the selective pressures that have shaped the diversity of life on Earth.

Question 22

what can we learn about evolution regarding the whale?

Answer 22

Evolution of snout-blowhole

The evidence for the evolution of whales from land-dwelling ancestors comes from a combination of:*fossil evidence, *comparative anatomy, *and genetic studies

Question 23

What do fossils teach us?

Answer 23

Confirm several predictions of evolutionary theory:
*gradual change within lineages *splitting of lineages
*the existence of transitional form

We find transitional forms in the fossil record precisely where they should be

Evolutionary change, even of a major sort, always involves remodelling the old into the new

legs of land animals ➔limbs of ancestral fish

Mammal’s middle ear bones➔jawbones of reptilian ancestors

Birds’ wings ➔the forelegs of dinosaurs

Question 24

does natural selection occur with new material?

Answer 24

no
Natural selection can act only by changing what already exists

New species will be modified versions of older ones

Question 25

what are Remnants: Vestiges, Embryos, and Bad Design

Answer 25

Within the bodies of animals and plants, lie clues to their ancestry, that are testimony to evolution

Question 26

where did most flightless birds evolve?

Answer 26

Most of the flightless birds evolved on islands due to inaccessibility

All places without mammals or reptiles predators!

Question 27

what is a vestigial trait?

Answer 27

A trait of a species that was an adaptation in its ancestors, but that has either:
*lost its usefulness completely
*has been coopted for new uses.

Ostrich’s wings don’t help to fly but:
-Stabilise run
-Threat display
-Mate dance

In birds, despite the use, the wings are made with the same bone

penguins- swimming

Kiwis- nothing

praying mantis- Display

Question 28

why might animals evolve away from flight

Answer 28

Flight is metabolically expensive, and if:
*No predators
*Food readily obtained on the ground

➔Flight energy can be diverted to reproduction or food
➔Reduce the chance of injuries

Natural selection would directly favour mutations that led to progressively smaller wings, resulting in an inability to fly.

Question 29

what is a Vestigial trait

Answer 29

An anatomical feature (or behaviour) that no longer seems to have a purpose in the current form of an organism of the given species

Question 30

what is atavism?

Answer 30

Atavism: trait reverting to ancestor form

Question 31

what are pseudogenes?

Answer 31

Non-coding sequences similar to working genes

Question 32

why is Comparative embryology important?

Answer 32

Ernst von Baer (1828):

*The more closely related any two species are, the more similar their development as embryos.

*Closely related species have similar embryological development

*Structure in embryo stage with no purpose and not present in adult

*Development diverges following weird routes…

Question 33

what is some Comparative embryology in vertebrates?

Answer 33

All vertebrates pass by the same developmental stages, all have:
*Branchial arches
*Tails
*Simple heart and circulatory system

Gill slits / branchial arches
Fish: Jaw and gills

Human: tiny bones of the middle ear, the Eustachian tube, the carotid artery, the tonsils, the larynx, and the cranial nerves

Question 34

what is the similarity in the vertebrate embryology of the circulatory system/kidney in invertebrates

Answer 34

Circulatory system/ Kidney: Starts fishlike ➔similar to embryonic amphibians ➔resembling that of embryonic reptiles ➔true mammalian circulatory system

Question 35

what is the reason for comparative embryology?

Answer 35

As one species evolves into another, the descendant inherits the developmental program of its ancestor and all the genes that form ancestral structures. “Adding new stuff onto old” principle

And this makes sense only if species have an evolutionary history

Question 36

how is imperfection evidence for evolution?

Answer 36

Every species is imperfect in many ways

Issues that only humans have: Fractured hips, bunions, hernias, fallen arches, torn meniscuses, shin splints, herniated discs, spondylolysis, scoliosis… and more

Question 37

Bad design: Recurrent Laryngeal Nerve

Answer 37

branch of the vagus nerve that supplies motor function and sensation to the larynx.

In fish, the nerve heads straight from the brain, down to the larynx
However, it is inefficiently evolved in mammals as it goes down to the heart and then back up to the larynx.

Possible explanation: Evolution doesn’t start from scratch. Organisms evolved features present in their ancestor

And this makes sense only if species have an evolutionary history

Question 38

what is biogeography?

Answer 38

“ the study of what organisms live where on earth and why”

Biogeographical patterns provide clues about how species, both alive and extinct, are related to each other.

Question 39

what is a biome?

Answer 39

A biome is an area classified according to the species that live in that location

Question 40

what is a reasonable non-evolutionary prediction?

Answer 40

A reasonable non-evolutionary prediction is that species should occur wherever their habitat is. However:

*Regions with identical climates have different floras and faunas

*Geographic barriers associated with breaks between taxonomic groups.

*Within a region, organisms are often closely related even across environmental gradients

Question 41

why do places have Similar Climate and Different Taxa?

Answer 41

Taxa are very different, but in similar environments they cover the same niches with similar aspect

convergent evolution: The evolution in different taxa of structures that are similar, NOT originated by common ancestry, due to similar selective pressures.

an example is Cacti and Euphorbs

or placental mammals and austrailian marsupials

Question 42

how do we know the supercontinent was real?

Answer 42

The earliest marsupial fossils (130 MYA) are found in in North America
*They arrive in Australia 50 MYA
*How did they do it??

Proof: Extinct marsupial family Polydolopidaefound in Seymour island

Oceanic islands

*Have a large number ofendemic species
*Miss many native species on continents
*Many species are very similar even if ecologically diverse
*Species are similar to ones on the closest continent
*Endemic species can disperse

Possible explanation:
*Organisms descended from species that colonized the islands
*Usually from nearby continents
*Long-distance dispersal
*Once there, they adapted to predator-free environment

ADAPTIVE RADIATION

Question 43

what is adaptive radiation?

Answer 43

Adaptive radiation is a process in evolutionary biology where a single ancestral species rapidly diversify into a wide variety of descendant species, each adapted to occupy different ecological niches or environments. This phenomenon often occurs when a group of organisms encounters new, diverse habitats with numerous unexploited ecological opportunities. Adaptive radiation leads to the emergence of multiple new species, each specialized to exploit a specific niche within their environment.

Question 44

what proves evolution?

Answer 44

If we take into consideration proofs from Anatomy, Fossils, Natural history, Embryology and Biogeography, we can see how evolution has shapes the organisms we see today