Chapter 14 - The plant and animal kingdoms / classification

CCEA GCE A2 2 BIOLOGY

What are the five kingdoms of classification?

• Prokaryotae

• Protocista

• Fungi

• Plantae

• Animalia

Characteristics of kingdom plantae?

• Multicellular

• eukaryotic cells

• cellulose cell walls

• photosynthesise using chlorophyll contained in chloroplasts

• show distinct differentiation with the cells in the different part of the plants specialised for specific functions

What are the two major plant groups?

• Bryophytes

• Tracheophytes

What is the Division Bryophyta represented by?

The mosses

Structure of division Bryophyta

• Lack true roots, stems and leaves

• Do not possess xylem or phloem i.e. no vascular tissue

• support is by turgor

• cells in the moss plant are organised intro structures that look superficially like stems and leaves and there are rhixoids which act to anchor the moss to the ground and are filamentous-like structures. Not true roots and incapable f penetrating the substratum, do not really take up water

• water and minerals can be absorbed across the whole surface of the moss plant

• the leaf-like structures do not possess a cuticle or stomata

• The moss is confined to where it can live. It must be in a damp, moist habitat as it has no vascular tissue and no way of restricting water loss.

• Do not grow very large

how do mosses avoid competition from grasses and other plants aswell as damage? (division Bryophyta)

By growing on stone walls and the roofs of buildings

Life cycle of mosses? (division Bryophyta)

Produce spores in a capsule at the end of a stalk that lifts the spore-producing capsule above the ground. This enables the spores rto be dispersed by wind currents

Why is it advantageous for a moss to produce spores the the end of a stalk? (division Bryophyta)

They are at a higher level to release spores into the air allowing wind to cary them and disperse/distribute. Reducing competition increasing their rate of survival

What does the spore producing structure possess? Why is this important and necessary? (division Bryophyta)

A stomata and cuticle which provide a degree of protection as this part of the moss plant extends above the main plant into the drier air.

Why would the spores dry out and not remain viable if away from moisture for too long? (division Bryophyta)

The spores germinate in moist conditions and are only partially resistant tp desiccation.

What type of plants are the Divison Tracheophyta?

Vascular plants, so have a vascular system xylem and phloem.W

What are the two major sub-divisions of the Tracheophyta?

• Ferns (pteridophytes)

• Flowering plants (spermatophytes)

Structure of sub-division Pteridophyta (ferns).

• True roots, stems and leaves

• vascular tissue in roots, stems and leaves: this allows ferns to grow bigger

• support via turgor and xylem thickened by lignin

• Presence of waterproof cuticle and stomata (allowing fine control and closure in times of water stress) in leaves, and true roots and stems with vascular tissue, allows colonisation of drier areas

• The stem, rhizome, runs horizontally underground with only the leaves extending above ground

• Ferns also disperse spores that germinate in damp conditions, not highly resistant to desiccation restricts ferns to relatively damp conditions

What are angiosperms? ( Sub-division spermatophyta)

flowering plants which are spermatophytes that produce flowers and seeds. They include small herbs to large trees

Structure of sub-division spermotphyta

• True roots, stems and leaves with a waterproof cuticle and stomata

• Highly specialised vascular tissue

• Roots are capable of ground penetration to absorb water and minerals

spermatophyta adaptations to life on land

• Root systems are even more complex

• Xylem is much more extensive and capable of providing much more support

• Seeds have a tough outer coat which provides protection against desiccation

• Seeds can remain dormant if they land in hostile environments, for many years

• Many seeds are highly adapted for dispersal by wind, animal or explosive means

What has the enormous diversity of flowering plants resulted in?

Different species being adapted for virtually all the habitats available on earth and can thrive in desert (xerophytes), rainforest and swamps, in water (hydrophytes)

General characteristsics of the Animalia Kingdom.

• Eukaryotic

• Multicellular

• Do not possess a cell wall

• Heterotrophic - feed on organic food that is digested internally

• most are capable of locomotion

What are the 4 Animalia?

• Phyla Cnidaria

• Platyhelminthes

• Annelida

• Chordata

body layer of the phylum Cnidaria

• bodies made of 2 layers separated by a non-cellular jelly layer - mesoglea

• outer layer called the ectoderm

• inner layer called endoderm which is in contact with gut cavity

• Diploblastic as has 2 body layers

• There are different cell types but there is very little differentiation and no organs

• They do not go actively hunting so locomotion is very restricted

• They have no means of controlling water loss across the body surface

Coelom of Cnidaria

Has none as they are diploblastic and do not have a mesoderm

Symmetry of cnidaria

Radially symmetrical

Feeding of Cnidaria

• The food is brought to the animal by the water currents

• All contain tentacles which have stinging cells called cnidocysts on them which when discharged, immobilise prey.

• Cnidocyst shoots out a barb which penetrates prey and injects a toxin which paralyses it

• The tentacles move the food into the fluid-filled enteron through the single opening or ‘mouth’

Digestion of Cnidaria

• There are digestive cells in the endoderm which secrete digestive enzymes into the enteron which start digestion

• This is extracellular digestion

• The partly digested food is absorbed int the endodermal cells by endocytosis so that digestion can be completed inside the cells intracellularly

Skeleton of Cnidaria

• They live in aquatic environments which provide them with support and therefore they do not need a hard skeleton

• They have a hydroskeleton formed by the fluid-filled gut cavity called the enteron

Organ systems of cnidarians?

Have no organs and organ systems

examples of Cnidarians

Corals, hyrdra, jellyfish

Examples of Phylum Platyhelminthes?

• Flatworms

• Parasitic or free living in damp environments

body layer of Platyhelminthes

• Triploblastic - have 3 body layers

• Endoderm, ectoderm and middle layer called mesoderm which splits the other two layers

• The mesoderm can become differentiated and form tissues such as nervous tissues and repoductive tissues

• Unlike mesoglea as it is made up of cells

What does the additional body layer of the Platyhelminthes result in and what is the solution?

• Results in increased distance between the surrounding medium and innermost layers of cells

• so Platyhelminthes are dorso-ventrally flattened to increase their surface area to volume ratio

Dorso-ventrally flattening in Platyhelminthes is benneficial why?

• Increases the uptake of oxygen due to increase surface area to volume ratio

• Decreases diffusion distance from body surface to body cells

Advantage of Plattyhelminthes being tripobastic?

Allows for greater differentiation and development of simple organs within the mesoderm

Problem of Plattyhelminthes being tripobastic?

Many cells per unit volume involved in metabolic activity, so high demand for oxygen and other metabolites

Coelom of Platyhelminthes?

There is no space for coelom within layers so acoelomate

Symmetry of Platyhelminthes

Bilaterally symmetrical

How is the bilaterally symmetry of the Platyhelminthes advantageous?

• As animal has a front where sensory receptors can be concentrated, allowing for information to be gathered about the environment into ehich it is proceeding

• Streamlined bilaterally symmetrical shape assists movement compared to radially symmetrical plan

• Aqueous ,medium supports the body and the mesoderm is mostly packing tissues for support

Feeding of Platyhelminthe

• Some are carnivores and active feeders

• Many are detritivores

• Planarians have a single openeing to the gut which means that food which cannot be digested has to be egested through the mouth

• Branched gut

Why is the gut branched in Platyhelminthes

• Food can be brought to all parts of the body by the gut.

• No requirement fot a circulatory system - No cell is very far from the permeable ectoderm

Digestion of Platyhelminthes

• Enzymes are secreted into the gut cavity and so digestion is initially extracellular and then endocytosis allows the partially digested food to be absorbed into the endodermal calles where digestion is completed intracellularly.

• Similar to cnidarians

Skeleton of Platyhelminthes

• No skeleton or anus

Examples of Annelida

• Earthworms

• lugworms

• ragworms

Body layer of Annelida

• Triploblastic but mesoderm is not a solid layer. it is divided into two by a coelom which is a space

• Metamerically segmented - body is divided into a large number of structurally similar segments. Most similar in structure. Dispite beng seperated the segments do not function independently of other segments

Coelom of Annelida

• Coelomate triploblasts

Advantages of a Coelom

• The ratio of surface area to metabolically active tissue is increased. Why they are round in TS. not the same requirement to maximise sa:vol ratio for respiration

• The fluid filled coelom can act as a hydrostatic skeleton

• Muscles involved in locomotion can be seperated from muscles involved with the gut. This allows perstaltic gut movements to continue and occur independently of movement

• Provides room for organs to grow

Feeding of Annelida

• Have a mouth and an anus ie a through gut

• Detritivores

• One way gut with a seperate mouth and anus allowing for regional specialisation and prevents egested food and newly ingested food getting mixed up

Digestion of Annelida

• Digestion completed in gut so is totally extracellular digestion

• Undigested food is egested via the anus and dorms worm casts

Skeleton of Annelida

• Ectoderm has cicular and longitudinal muscles

• These worl antagonistically, contrastinf in turn against the hydrostatic skeleton

• External chaetae are able to produce friction allowing the worm to move

Organ systems of Annelida

• Muscular pharynx (adjacent to mouth), oesophagus, crop (storage area), muscular gizzard ( for mechanical digestion) and an intestine for absorption

Examples of Phylum Arthropoda

Insects and spiders

Symmetry of Arthropods?

Bilaterally symmetrical

Body plan of arthropods

• typically have a fixed number of metameric segments in each region of the body

• insects typically have 3 segments in the thorax and 10-11 in abdomen

• possess 3 pairs of Jointed limbs, one on each segment of the thorax

• Mouth and anus, gut shows regional specialisation

• Possess an external skeleton: exoskeleton

Symmetry of Arachnids?

Bilaterally symmetrical

Body plan of Arachnids

• Fixed number of metameric segments

• 4 pairs of legs (8)

• Body has 2 main sections - the head and thorax are combined to form the cephalothorax

Why are the arthropods and insects the most successful animal group on Earth?

• Basic insect body plan can be easily adapted to fill wide range of niches

• Insects mouthparts have evolved for chewing (locusts) or piercing skin (mosquitoes), piercing plants (aphids) or sucking fluids (houseflies)

• Many insects have wings for flight and many species have separate distinct body forms eg larval (caterpillars) and adult forms which use different food sources

• Possess an external skeleton: exoskeleton

Examples of Phylum Chordata

Vertebrates are chordates and contain the following groups:

• Fish

• Amphibians

• rEPTILES

• bIRDS

• Mammals

Chordata symmetry?

Bilaterally symmetrical

Coelom of chordata?

Coleomate triploblastic

type of gut chordata possess?

• complex gut with a high degree of regional specialisation

• one way gut with a mouth and anus

Body plan of chordata?

• metamerically segmented but much less obvious in annelids

• body cabity (coelom) is much greater in extent proportionally and more continuous than in annelids and more continuous than in ennelifs and contains more extensivelt developed and complex organ s which are organised into complex systems

• In vertrbrates there is a vertebbral column with segmented blocks and a post anal tail with the skeleton consisting of internal jointed system of calcified bones

• in some chordates they do not possess a vertebral column but have s stiff dorsal rod (notochord) - small nonvertabrate chordates, rare group evolutionarry bridge between inverebrates and vertebrates

skeleton of chordates

• In vertrbrates there is a vertebbral column with segmented blocks and a post anal tail with the skeleton consisting of internal jointed system of calcified bones

• Endoskeleton

Digestion in chordates?

• Extracellular and abosrbed food products are distributed to all body cells via the well-developed circulatory system.