What is a species?

Question 1

What do we use to measure biodiversity?

Answer 1

Species numbers

Question 2

What was the definition of species defined by Linnaeus?

Answer 2

A morphological species concept, based solely on apperance of the organisms being observed

Question 3

How do scientist group organisms into species?

Answer 3

Use the degree of similarities and differences of the physical characteristics`

Question 4

What is the classfication system based on?

Answer 4

Morphology

Question 5

What is the disadvantage of using the morphological species concept?

Answer 5

Appearance of organisms cen be affected by different things, so there could be variation within a group of related organisms

Question 6

What is the second disadvnatage of using the morphological species concept?

Answer 6

In organisms that show sexual dimorphism, there is a great deal of difference between male and female, the different sexes could well be thought to be different species in a morphological species model.

Question 7

What was the new definition of species?

Answer 7

A group of organisms with similar characteristics that interbreed to produce fertile offspring

Question 8

What does the new definition of species overcome?

Answer 8

Sexual dimorphism

Question 9

What are the limitations of the new defintion of species?

Answer 9

All the organisms within a species cannot attempt to interbreed to produce offspring because they do not all live in the same area

Question 10

What is the second disadvantage of the new defintion of species?

Answer 10

Populations of the same species cannot interbreed because they are in different places.

Question 11

What happens if two individuals from different populations mate?

Answer 11

they are considered the same species if fertile offspring are produced and genes are combined or flow from the parents to the offspring

Question 12

What hapens if the genes cannot flow to the next generations when two individuals from different populations mate?

Answer 12

They are not the same species

Question 13

How can we overcome these limitations that have been created due to the new definition of species?

Answer 13

Two more defintions are created and they are based on reproductive capability

Question 14

What are the two new defintions of species?

Answer 14

1. A group of organisms with similar characteristics that are all potentially capable of breeding to produce fertile offspring
2. A group of organisms in which genes can flow between individuals

Question 15

What is DNA and RNA like withinn a species?

Answer 15

1. Universal
2. Similar across all species
3. But may have some differences when the molecule are broken down into their constituent parts

Question 16

What can the differences of RNA and DNA within similar species be used for?

Answer 16

Science of molecular phylogeny

To build up new models of species and their relationships

Question 17

What are the 4 models of species?

Answer 17

Ecological species model
Mate recognition species model
Genetic species model
Evolutionary species model

Question 18

What is ecological species model based on?

Answer 18

The ecological niche occupied by organsims

Question 19

What are the limitations of ecological species

Answer 19

Not very robust, as niche definitions vary and many species occupy more than one niche

Question 20

What is the mate recognition species model based on?

Answer 20

Unique fertilisation systems, incluidng mating behaviours

Question 21

What are the limitations of mate recognition species model?

Answer 21

Difficult as many species will mate with or cross pollinate other species and may even produce fertile offspring, but they are still different species.

Question 22

What is the genetic species model based on?

Answer 22

DNA evidence

Question 23

Limitations of the Genetic species model?

Answer 23

People still have to decide how much genetic difference makes two organisms members of different species

Question 24

What is the evolutionary species model based on?

Answer 24

Based on shared evolutionary relationships between species.

In this model, members of a species have a shared evolution and are evolving together.

Question 25

Limitations of the evolutionary species model?

Answer 25

However, there is not always a clear evolutionary pathway for a particular organism

Question 26

What are the limitations of the ways to define species?

Answer 26

Finding the evidence: living species have not been observed mating
Setting up a breeding program is time-consuming
Expensive
May not prove anything

Question 27

What are the second limitations of the ways to define species?

Answer 27

Plants of different but closely related species interbreed and produce fertile hybrids
At what point would the hybrids be regarded as a different species?

Question 28

What are the third limitations of the ways to define species?

Answer 28

Many organisms do not reproduce sexually
Any definitions of reproduction are not relevant for:
Fungi
Protists
These mainly reproduce asexually

Question 29

What is the fourth limitation of the ways to define species?

Answer 29

Fossil organisms cannot reproduce and do not have any accessible DNA, but they still need to be classified

Question 30

What can be used to identify an organism?

Answer 30

Information technology provides an ideal tool to help scientists answer these questions from simple identification apps to help decide which bird etc you have seen
There are also instruments that will identify DNA