the evolution of living things

The EVOLUTION of Living Things

What characteristics of the following animals improve their ability to survive?

Change Over Time

ADAPTATION: a characteristic that improves

an individual’s ability to survive and reproduce in a

particular environment.

What is a species?

Change Over Time

SPECIES: a group of organisms that are closely

related and can mate to produce fertile offspring.

What is a species?

Change Over Time

A mule is the offspring of a male donkey and a

female horse. Mules are not fertile. Are horses and donkeys from the

same species?

Do species change over time?

Change Over Time

The planet is 4.6 billion

years old. In this time,

many species

have died out, and

many new species

have appeared.

The processes that have transformed life on Earth from

its earliest forms to the vast diversity that characterizes it

today is known as EVOLUTION.

Evidences of evolution

Change Over Time

Fossil Record A fossil is the preserved remains or traces of any organism from the remote past

Fossil evidence may be one of two types

• Direct or body fossils (bones, teeth, shells, leaves, etc.)

• Indirect or trace fossils (footprints, tooth marks, burrows, etc.)


Change Over Time

Fossil Record

Fish to amphibians

Fossils show a chronological (time) sequence in which

characteristics appear and develop in

complexity

http://www.pbs.org/wgbh/nova/evolution/fossil-evidence.html


Change Over Time

Fossil Record

Fossils have been discovered of many types of organism

that no longer exist, e.g. trilobites and dinosaurs.

In most cases no fossils can be found of organisms that

do exist today.

This suggests that the ancestral species evolved into

the modern species


Change Over Time

Fossil Record

TIKTAALIK. This creature is a mosaic of fish and land features. It has scales and fins like a fish but flat head with eyes on top, a neck, shoulder, elbow, and wrist. It is telling us that this is a fish that can live in the shallows and even make short excursions on to land.

ARCHAEOPTERYX. Combination of reptilian and distinctly bird-like characteristics, mouth full of teeth, long tail and feathery, clawed arms, appeared to be a true missing link between reptiles and birds.

Bird-reptile transition Land-sea transition

Transitional fossils show the links between groups or species by exhibits traits common to both the ancestral group/species and its derived descendant group/species.


Change Over Time

Fossil Record

There are gaps in the fossil record due to:•Special circumstances are required for fossilization to occur•Only hard parts of an organism are preserved•Fossils can be damaged so that only fragments remain to be discovered

The fossil record is the sum of all discovered and undiscovered fossils and their relative placement in rock.Provides the dimension of time to the study of evolution – the layer of rock in which a fossil is found can be dated and therefore used to deduce the age of the fossil.


Change Over Time

Fossil Record

DNA Comparisons Human beings have approx. (genes in common with):

96% with chimpanzees

90% with cats

80% with cows

75% with mice


Change Over Time

Fossil Record

DNA Comparisons Human beings have approx. (genes in common with):

This does not prove that Beyonce evolved from chimpanzees or cats,

though, only that we shared a common ancestor in the past. And the amount of difference between our

genomes corresponds to how long ago our genetic

lines diverged.


Change Over Time

Fossil Record

DNA Comparisons

Phylogenetic tree is a diagram showing the evolutionary interrelations of a group of organisms derived from a common ancestral form. The ancestor is in the tree “trunk”; organisms that have arisen from it are placed at the ends of tree “branches.” The distance of one group from the other groups indicates the degree of relationship; i.e., closely related groups are located on branches close to one another.


Change Over Time

Fossil Record

DNA Comparisons

Place the following organisms in the phylogenetic tree:•Human•Fish•Chicken•Mouse•Frog


Change Over Time

Fossil Record

DNA Comparisons

Homologous Structures

Homologous structures or comparative anatomy of groups of animals or plants shows certain structural features are basically similar. Structures or anatomical features having similar basic structure as in other species said to be homologous.


Change Over Time

Fossil Record

DNA Comparisons


homologous structures used in different ways in different species


Change Over Time

Fossil Record

DNA Comparisons


The structural similarities imply a common ancestry

This illustrates adaptive radiation since the basic structure adapted to different niches

The more exclusive the shared homologies the closer two organisms are related.


Change Over Time

Fossil Record

DNA Comparisons


Vestigial Structures

A very interesting type of homologous structure is the one that may have served a function in the evolutionary past, but in the modern species has no function at all.

The pelvis and femur of a whale are examples.

The structural similarities imply a common ancestry


Change Over Time

Fossil Record

DNA Comparisons



Initially, all chordate embryos strongly resemble each other. These could only be possible if all Chordata descended from a common ancestor mans, dogs, snakes, fish, monkeys, eels are all considered "chordates" (belong to the phylum Chordata).

Embryology & Development


Change Over Time

Fossil Record

DNA Comparisons



One of the features of this phylum is that, as embryos, all these life forms have gill slits, tails, and specific anatomical structures. For humans, gill slits reform into the bones of the ear and jaw at a later stage in development. Embryology & Development


Change Over Time

Scientists believe that whales evolved from land-based mammals. What three pieces of evidence support possibility? • Existence of

unused hip bones in modern whales

• Whales are mammals

• Existence of a large number of fossils.


Change Over Time

How do scientists use the location of fossil discoveries to determine the order in which different organisms lived on Earth? Since the layers of

the Earth form in an orderly fashion, scientists know that the deeper layers were formed before the upper layers. By knowing the layers in which fossils were found, scientists can determine the relative ages of different fossil.

Charles Darwin

How Does Evolution Happen?

Charles Darwin's theory of evolution by natural selection made us rethink our place in the world.

The man who

struggled with his

own ideas

The idea that humans shared a common ancestor with apes was a challenge to the foundations of western civilization

Charles Darwin


Setting sail around the world

Darwin’s tutor at Cambridge recommended him as a ‘gentleman naturalist’ on a voyage around the world on HMS Beagle. Darwin jumped at the chance.Over the following five years, Darwin visited four continents, spending much of his time on land collecting specimens and investigating the local geology.

Charles Darwin


Darwin’s Finches

Darwin noticed that each island supported its own form of finch which were closely related but differed in important ways.

What difference did Darwin observe among the different species of Galápagos finches?

Their different beaks are adaptations that evolved because the different finches needed to get food in different ways.

Why do the Galápagos finches have different beaks?

Charles Darwin


Darwin’s Thinking

Breeding Population Earth’s History

Charles Darwin


Darwin’s Thinking


Farmers and breeders had produced many kinds of plants and animals with the desired characteristics (selective breeding).

Species can produce many offspring, but populations are limited by starvation, disease, competition and predation. Only a limited number of individuals survive to reproduce.

The Earth was very old and species could evolved over this time.

Charles Darwin


Darwin’s Thinking


Is the process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals.

Theory of natural selection

• Phenotypic variation exists among individuals and the variation is heritable.

• More individuals are produced each generation that can survive.

• When reproductive isolation occurs new species will form.

• Those individuals with heritable traits better suited to the environment will survive.

Charles Darwin


Darwin’s Thinking


Is the process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals.

Theory of natural selection

Sketch the four parts of natural selection providing an example (different from tarantulas and

giraffes)

Charles Darwin


Changes in Population

The Theory of Natural Selection explains how populations are change in response to the environment. Peppered Moth ('Darwin's moth‘)

There is also a naturally occurring genetic mutation which causes some moths to have almost black wings.

Are normally white with black speckles across the wings (camouflaged against lichen-covered tree trunks).

Charles Darwin



The Theory of Natural Selection explains how populations are change in response to the environment. Peppered Moth ('Darwin's moth‘)

These black forms are not as well camouflaged on the lichen as normal 'peppered' forms and so they are more likely to be eaten by birds and other predators.

Industrialization and domestic coal fires had caused sooty air pollution which had killed off lichens and blackened urban tree trunks and walls.

In the mid-twentieth century controls were introduced to reduce air pollution and as the air quality improved tree trunks became cleaner and lichen growth increased.

What was the effect in moth’s population?

Charles Darwin



The Theory of Natural Selection explains how populations are change in response to the environment.

Peppered Moth ('Darwin's moth‘)

Use this information to create a graph of the paper Moth population over time

Charles Darwin



The Theory of Natural Selection explains how populations are change in response to the environment.

Peppered Moth ('Darwin's moth‘)

In the mid-twentieth century controls were introduced to reduce air pollution and as the air quality improved tree trunks became cleaner and lichen growth increased.

Use this information to create a graph of the paper Moth population over time

Continue the graph with the new information

Charles Darwin


Defend Evolution!

Record a video-interview, video debate, theater play or any other video explaining evolution and its evidences.

the evolution of living things

Science