The smart way to improve grades

Comprehensive & curriculum aligned

Affordable pricing from £10/month

Speciation

In this worksheet, students will study the evolution of new species and the factors that determine extinction. It continues on from Year 10 worksheet Evolution and Survival.

Worksheet Overview

QUESTION 1 of 10

Fossils are the only evidence we have of organisms that lived thousands of years ago and are now extinct. Fossils are the traces or remains of dead animals and plants that had their hard parts, like bones, replaced by other materials as they decayed. For example, here is an ammonite fossil - the fosillised form of a marine animal that lived thousands of years ago:

 

Image of a troglodyte.

 

They also provide evidence for the evolution of species, i.e. how organisms changed over time. This is called speciation. A species is a group of organisms which have the same characteristics.

 

Domestic dogs, for example, belong to the same species and can breed, which means they can mate to reproduce. Their young are fertile. Are you wondering how all dogs can belong to the same species when they look so different? This is because humans have bred lots of different types. Horses and donkeys belong to different species, but they interbreed and produce mules. Mules are not a species, because they are sterile, which means that they CANNOT reproduce.
 

Cats (not just domestic ones) belong to the same family. Tigers and lions are also cats, each belonging to a different species. They do not naturally interbreed. However, scientists have interbred them and they produced a tigon, which is sterile. Like mules, tigons are hybrids. A hybrid is an animal produced when two different species interbreed. This is only possible when the species belong to the same family. Lions and tigers share a recent ancestor but have evolved to live in different habitats; lions in open grassland and tigers in the forest.

 

 

There are two main theories of evolution, but the one that Charles Darwin developed is the one that was accepted widely and is still believed. However, all theories of evolution have a common explanation behind them and they are related to the organisms being adapted to their environment so they can survive. Environments do change, however. If an organism is to survive, it needs to adapt to the changing environment. In any species, only the fittest individuals survive. This is called natural selection. The fittest survivors have characteristics best suited to their environment. Because they survive, they reproduce and pass their characteristics to the next generation through genes (DNA). If they needed to change to adapt better, over time, many changes could lead to a new species. Therefore, speciation is actually a result of changing conditions, like the surrounding environment, a new predator, a disease and so on. This is the theory of evolution according to Charles Darwin.

 


The diagram below shows how the horse evolved to the form we know it today over millions of years. Horses actually had toes to start with, which were gradually replaced by a hoof:

 

Image of the evolution of a horses leg.
 

Over 60 million years ago, horses lived in the rain forest. They were as small as a dog and had toes. However, horses today have hooves and are over 2m tall. The ground in the rainforest was covered with leaves and was protected by trees, so horses had no problem walking on it. As the environment changed hooves developed gradually, so horses could run on muddy open country plains. The height of the horse increased and that was again an adaptation for running in open country.

Where does evidence for evolution come from? Type the word in the answer box below.

What do we call evolution of new species? Type the word in the answer box below.

What is a species?

A group of organisms that live in the same area

A group of organisms that are identical

A group of organisms that share the same characteristics

Is the following statement true or false?

 

When two species interbreed, a new species is created.

True

False

What does the phrase 'survival of the fittest' describe?

Speciation

Natural selection

Evolution

In the answer box below, write the word which completes this sentence:

 

All cats belong to the same __________.

How has the horse changed over million of years? Two statements apply.

It is now much shorter

It now has hooves instead of toes

It is now much taller

It now has toes instead of hooves

This is a picture of the dodo:

 

Image of a Dodo

 

It used to live in Mauritius, which was uninhabited until the 1600s. The dodo became extinct 80 years after man arrived on the island. Suggest two reasons why.

It was hunted for food

It was not tasty

It ate a variety of food

Competitor animals were introduced to the island with humans and food was not as readily available for the dodo as before

Another reason for speciation is isolation. The Galapagos Islands, which Charles Darwin researched thoroughly, were too far from the coast of South America for animals and birds to travel to and from. Species that lived in the Galapagos Islands were, therefore, distinct from similar species that lived in South America and adapted very well to their environment.

 

Image of a finch   Image of a finch

 

The images above show two finches that have different beaks. Suggest a reason for this.

They are camouflaged in their environment

They are adapted to hunting wild animals

They are adapted to eating different types of food, i.e. insects or seeds

The image below is of a giant tortoise, the biggest species of tortoise in the whole world.

 

Image of a giant tortoise

 

Suggest why it only lives in the Galapagos Islands.

Isolation

Speciation

Distribution

  • Question 1

Where does evidence for evolution come from? Type the word in the answer box below.

CORRECT ANSWER
fossils
EDDIE SAYS
Fossils are the evidence we have of organisms that lived thousands of years ago and are now extinct. They provide evidence for evolution and, also, evidence for the evolution of species, i.e. how organisms change over time.
  • Question 2

What do we call evolution of new species? Type the word in the answer box below.

CORRECT ANSWER
speciation
EDDIE SAYS
Speciation is defined as 'the formation of new and distinct species during the course of evolution'. This happens when the two animals are not able to make offspring that can breed together. For example, you can breed a lion and a tiger to get a liger - but you can't breed two ligers as they don't make working sperm and eggs. But you can breed together a boxer dog and a husky, they are both the same species.
  • Question 3

What is a species?

CORRECT ANSWER
A group of organisms that share the same characteristics
EDDIE SAYS
A species is a group of organisms that share the same characteristics. However, they are not identical, as there is variation within a species, and they can also live in different areas all over the world. Also, all of that stuff about breeding that came up in the explanation to the last question.
  • Question 4

Is the following statement true or false?

 

When two species interbreed, a new species is created.

CORRECT ANSWER
False
EDDIE SAYS
When two species interbreed a hybrid is created, but it is not a new species because it is sterile, i.e. it cannot reproduce.
  • Question 5

What does the phrase 'survival of the fittest' describe?

CORRECT ANSWER
Natural selection
EDDIE SAYS
Survival of the fittest means the survival of the organisms that are best adapted to their environment and those that are not well adapted becoming extinct (dying out) or moving away; this is natural selection.
  • Question 6

In the answer box below, write the word which completes this sentence:

 

All cats belong to the same __________.

CORRECT ANSWER
family
EDDIE SAYS
All cats belong to the same family - and within that family are different species. For example, within the cat family there are domestic cats, tigers, lions, panthers etc...
  • Question 7

How has the horse changed over million of years? Two statements apply.

CORRECT ANSWER
It now has hooves instead of toes
It is now much taller
EDDIE SAYS
Horses as we know them now have hooves instead of toes and are much taller. This is because they have evolved to suit the changing environment, from soft rainforest floors to hard country plains.
  • Question 8

This is a picture of the dodo:

 

Image of a Dodo

 

It used to live in Mauritius, which was uninhabited until the 1600s. The dodo became extinct 80 years after man arrived on the island. Suggest two reasons why.

CORRECT ANSWER
It was hunted for food
Competitor animals were introduced to the island with humans and food was not as readily available for the dodo as before
EDDIE SAYS
The dodo was hunted for food by the humans. Competitor animals were also introduced to the island with the humans, meaning that the food on the island was not as readily available for the dodo as before. It was unable to evolve to suit these sudden changes and, therefore, died out (became extinct).
  • Question 9

Another reason for speciation is isolation. The Galapagos Islands, which Charles Darwin researched thoroughly, were too far from the coast of South America for animals and birds to travel to and from. Species that lived in the Galapagos Islands were, therefore, distinct from similar species that lived in South America and adapted very well to their environment.

 

Image of a finch   Image of a finch

 

The images above show two finches that have different beaks. Suggest a reason for this.

CORRECT ANSWER
They are adapted to eating different types of food, i.e. insects or seeds
EDDIE SAYS
The birds have developed different shaped beaks as they have adapted to the food in their different countries.
  • Question 10

The image below is of a giant tortoise, the biggest species of tortoise in the whole world.

 

Image of a giant tortoise

 

Suggest why it only lives in the Galapagos Islands.

CORRECT ANSWER
Isolation
EDDIE SAYS
The giant tortoise lives only in the Galapagos Islands due to isolation. This means that the Galapagos Islands were too far away from any other country for the tortoises to travel to, and so they have become isolated the islands as a result of this.
---- OR ----

Sign up for a £1 trial so you can track and measure your child's progress on this activity.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started
laptop

Start your £1 trial today.
Subscribe from £10/month.