Revised Topic 1 deck — Version 1

What are the seven characteristics of living organisms?

Movement, respiration, sensitivity, growth, reproduction, excretion and nutrition. (MRS GREN)

1.A) Define movement?

1.B) Give one example of movment in a plant

1.A) An action by an organism or part of an organism causing a change of position or place

1.B) Example : A shoot grows towards light

Define respiration

The chemcial reactions in cells that break down nutrient molecules and release energy for metabolism

Define sensitivity

The ability to detec and respond to changes in the internal or external environment

Define growth

A permanent increase in size and dry mass

Define reproduction

The process that make more of the same kind of organism

Define excretion

The removal of :

1. Waste products of metabolism

2. Substances in excess of requirements

Define nutrition?

The taking in of materials for:

1. Energy

2. Growth

3. Development

How does breathing differ to respiration?

1. Breathing is the physical movement of air into and out of the gas-exchange organs

2. Respiration is the chemcial process in cells that releases energy from nutrient molecules

Why is growth defined using "dry mass" rather than simply an increase in size?

An organism may increase in size because of water uptake, whereas an increase in "dry mass" indicates that new biological material has been produced

On what basis are orgaisms classified into groups?

Organisms are classified according to features they share

Define a species

A group of orgaisms that can reproduce with each other to produce fertile offspring

1.A) How does binomial nomenclature name organisms

1.B) Why is this method useful?

1.A) Each species has a two-part scientific name, the genus and species in that order

1.B) It is internationally agreed on and recognized, avoiding confusion caused by different common names and languages

What is a dichotomous key?

A method of identifying organisms using a series of pairs of contrasting statements based on identifiable features

What rules should be followed when constructing a dichtomous key?

1. Each step gives two contrasting choices

2. Choices are based on identifiable/observable features

3. Each choice directs the user to another pair or to an identification

Study Fig 1.1 Which group of arthropod does the organism shown belong too? Give two features visible in Fig 1.1 that support your answer

Group : Myriapod

Features : 1. Numerous pairs of legs 2. Numerous body segments

Why do modern classification systems aim to reflect evolutionary relationships

Organisms that share a more recent common ancestor are more closely related and should therefore be classified more closely together

Organism A and B have 96% similarity in their DNA base sequences. A and C have 81% similarity. Which pair is more closely related? Explain

A and B, because

Their DNA base sequences are more similar; this indicates that they share a more recent common ancestor

Within the five-kingdom system, how are organisms in the animal and plant kingdoms distinguished?

Animals :

1. Multicellular

2. Cells have no cell walls or chloroplasts

3. Obtain nutrients by feeding on other organisms

Plants :

1. Multicellular

2. Cells have cellulose cell walls and chloroplasts

3. Make nutrients by photosyntheis

Within the five-kingdom system, what features idenfity organisms as fungi?

1. Cell wallas contain chitin

2. Usually consist of hypahe forming a mycelium

3. Obtain nutrients by external digestion followed by absorption

Within the five-kingdom system, how can prokaryotes be distinguished from protoctists?

Prokaryotes :

1. Usually unicellular

2. Have no nucleus

3. Genetric material occurs as circular DNA

Protoctists

1. Mostly unicellular

2. Cells contain a nucleus

3. Some contain chloroplasts and photosynthesise, while others do not and obtain nutrients from other ogranisms

What are the main idenfitying features of mammals?

1. Have hair or fur

2. Females have mammary glands and produce milk for offspring

3. Have external ears

What are the main identifying features of birds?

1. Have feathers

2. Have a beak

3. Have wings

What are the main identifying features of reptiles?

1. Have dry, scaly skin

2. Breathe using lungs

3. Lay egges with leathery/waterproof shells

What are the main identifying features of amphibians?

1. Have moist skin

2. Lay eggs in water

3. Young usually develop in water before becoming adults adapted to life on land

What are the main identifying features of fish

1. Have gills

2. Have fins

3. Usually have scales

Answer 11.a

Mulanje

What three features identify an organism as an arthropod?

1. Segmented body

2. Jointed limbs

3. Exoskeleton

What are the mainidenfitying features of insects?

1. Three pairs of legs

2. One pair of antennae

3. Body divided into head, thorax and abdomen

What are the main identifying features of arachnids?

1. Four pairs of legs

2. No antennae

3. Body divided into two main regions

What are the main identifying features of crustaceans?

1. More than three pairs of legs

2. Two pairs of antennae

3. Usually have a hard exoskeleton

What are the main identifying features of myriapods?

1. Many body segments

2. Many pairs of legs

3. One pair of antennae

How can ferns be distinguished from flowering plants?

1. Ferns reproduce using spores and do not produce flowers

2. Flowering plants produce flowers and reproduce using seeds

Give three features that distinguish monocotyledons from dicotyledons

1. Monocotyledons have 1 cotyledon/Dicotyledons have 2

2. Monocotyledons have parallel leaf veins/Dicotyledons have reticulate/net-like leaf veins

3. Monocotyledons flowers part in multiples of 3/Dicotyldons flowers part in multiples of 4 or 5

What are the two basic structural features of a virus?

1. Genetic material

2. Protein coat

Study Fig 1.2 and answer the following questions

1. (Hard) shell/ exoskeleton / carapace

2. Animal

Study Fig 1.1. State two features visible in Fig 1.1 that can be used to identify this organism as an arachnid

any two from :

8 legs/ 4 pairs of legs

two-part body ; body made of head and cephalothorax

Study this image. Identify whether the plant shown is a monoctoyledon or a dicotyledon. Give two features visible in the figure that support your answer

Monocotyledon

Features :

1. Parallel leaf veins

2. Flower parts in multiples of three (six in this case)

Answer the question shown in the image

B

An organism is multicellular. It's cells have walls made of chitin, and it obtains nutrients by secreting digestive enzymes onto its food and absorbing the products. Which kingdom does it belong to and why?

Fungus, because of the chitin cell walls and external digestion followed by absorption

Scientists compare the DNA of three species:

A and B: 97% similar

A and C: 82% similar

B and C: 81% similar

Which two species probably share the most recent common ancestor? Explain

A and B, because they have the greatest similairty in their DNA base sequencs, indicating a more recent common ancestor