Unit 1 - Characteristics and Classification of living organisms

Question 1

Characteristics of living things:

Answer 1

MRS GREN
1. Movement
2. Respiration
3. Sensitivity
4. Growth
5. Reproduction
6. Excretion
7. Nutrition
(Homeostasis)

Question 2

Who created the Binomial system?

Answer 2

Carl Linnaeus of Sweden in 1735 introduced the basis of modern taxonomy (classification). He classified organisms based on how similar they looked (their morphology (shape) or anatomy).

Question 3

How to write out the name of any given species

Answer 3

All living organisms are given two names in Latin to show how closely related they are to each other.
1 Genus name, written first and starts with a capital letter,
2. species name, written second and starts with a small letter
When it’s typed, the name is written in Italics
When handwritten it is simply underlined

Question 4

The sequence of classification is:

Answer 4

Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 5

Why do organisms share features?

Answer 5

Organisms share features because they originally descend from a common ancestor

Question 6

How were organisms originally classified?

Answer 6

Originally, organisms were classified using morphology (the overall form and shape of the organism, e.g. whether it had wings or legs) and anatomy (the detailed body structure as determined by dissection)

Question 7

What do we use now and why?

Answer 7

RNA and DNA sequencing sequencing allows us to classify organisms using a more scientific approach

Question 8

What does studying DNA sequences show us about organisms?

Answer 8

Studies of DNA sequences of different species show that the more similar the base sequences in the DNA of two species, the more closely related those two species
are (and the more recent in time their common ancestor is).
This means that the base sequences in a mammal’s DNA are more closely related to all other mammals than to any other vertebrate groups

Question 9

What is the study of RNA and DNA sequencing called? How is it different to taxonomy?

Answer 9

Cladistics shows us how we are related on a biochemical level (DNA/RNA), while taxonomic classification is based on visible, physical features. Cladistics is a more accurate, scientific way of classification.

Question 10

What other features have organisms been grouped together with in the past?

Answer 10

• Physical Features i.e. teeth, wings, scales
• Habitat
• Methods of Nutrition
• Methods of reproduction, including if organisms were capable of interbreeding
• Life cycle

Question 11

The cells of all living organisms contain the following:

Answer 11

• Cytoplasm
• Cell membrane
• DNA as genetic material (either found in the nucleus or free in the cytoplasm)

Question 12

Main features of all animals:

Answer 12

• They are multicellular
• Their cells contain a:
- nucleus (eukaryotic, contains double-stranded DNA)
- cell membrane made of fats and proteins
- cytoplasm containing mitochondria (respiration) and
glycogen granules (sugar storage).
• Heterotrophic so must feed on other living things for energy

Question 13

Main features of all plants:

Answer 13

• They are multicellular
  • Their cells contain a:
  - nucleus (eukaryotic, contains double-stranded DNA),
  - chloroplasts and cellulose cell walls
  - cell membrane made of fats and proteins.
  • They all feed by photosynthesis

Question 14

Main features of all Protoctists

e.g. Amoeba, Paramecium, Plasmodium

Answer 14

• Most are unicellular but some are multicellular
• All have a nucleus, some may have cell walls and chloroplasts
• This means that some protoctists photosynthesise and some feed on organic
substances made by other living things