BIO10010 L2-9

Types of biodiversity

Genetic, species and ecosystem

Types of genetic diversity

Allelic diversity, heterozygosity and nucleotide diversity

What is species richness?

The number of different species

What is species evenness?

The ratio of organisms in each population

What does a larger Shannon index value indicate?

Greater diversity

Provisioning services

Provides food and water

Regulating services

Regulates water and air quality

Why is biodiversity measured?

• To detect changes and trends

• To understand how we can maintain diversity

What increases species richness?

Immigration or speciation

What decreases species richness?

Local extinction or emigration

What is classification based on?

Morphology, behaviour and development

Paraphyletic group

Includes common ancestor but not all its descendants

Polyphyletic group

Doesn’t include common ancestor

Monophyletic group

Includes common ancestor and all its descendants

Features of bacteria

• Prokaryotic

• Unicellular

• Metabolically diverse

Features of archaea

• Prokaryotic

• Found in extreme environments

• Evolutionary closer to eukaryotes

Features of eukarya

• Membrane bound nucleus and organelles

• Unicellular and multicellular

• Cells divide by mitosis and meiosis

Features of protists

• Mostly unicellular

• Some animal-like

• Some plant-like

Features of plants

• Multicellular

• Autotrophic

Features of fungi

• Usually multicellular

• Heterotrophic

• External digestion

• Non-motile

Features of animals

• Multicellular

• Heterotrophic

• Internal digestion

Why are insects so successful?

• High reproductive rates

• High genetic diversity

• Small size

• Evolution of wings

Role of denitrifiers

Convert nitrate ions to N2

Role of nitrogen fixers

Convert N2 to NH3

What organisms act as nitrogen fixers?

Archaea and bacteria

Role of cyanobacteria

Splits water and generates O2 as a waste resource

Symbiotic relationship between insects and protists

Use of abundant but poor quality food source

How do decomposers improve plant nutrition?

They release nutrients into soil

Symbiotic relationship between humans and flora or microbiome

• Aids digestion

• Synthesises essential vitamins

• Protects against pathogenic infections

Examples of macronutrients

Amino acids, lipids and carbohydrates

Example of micronutrients

Minerals and vitamins

Fat-soluble vitamins

A, D, E, K

Water-soluble vitamins

B and C

How are vitamins obtained?

From food

Vitamin deficiency diseases

• Rickets

• Scurvy

• Hypervitaminosis A

Minerals needed in high amounts

Na, Cl, K

Minerals needed in small amounts

Fe, Cu, F

How do autotrophs acquire nutrients?

Photosynthesis and chemosynthesis

Heterotrophic adaptations

• Mechanical digestion

• Chemical digestion

• Absorption

Autotrophic adaptations

• Roots

• Leaves

How do fungi digest food?

• Hyphae grow over food

• Fungal exudate is released

Gastrovascular cavities

Sponges, cnidarians and flatworms

Digestive systems in carnivores

• Short gut

• No specialisations

Digestive systems in omnivores

• Longer gut

• May have some specialisations

Digestive systems in herbivores

• Very long gut

Why are long guts useful?

To increase uptake of nutrients of plants

Sites of mechanical digestion

• Mouth

• Stomach

Sites of chemical digestion

• Mouth

• Stomach

• Small intestine

Sites of microbial digestion

• Stomach

• Small intestine

• Caecum

• Large intestine

How does excretion regulate the internal environment?

• Controls body water content

• Maintains solute composition

• Excretes metabolic waste

What is secretion?

Movement of material that has a specific task after leaving the organism

Osmoregulators

Maintains a stable internal water and ionic composition

Osmoconformers

Matches internal composition to the surrounding environment

Ways to prevent water loss in deserts

• Nocturnal activity

• Efficient kidneys

• Water storage

Ammonotelic excretion

Aquatic invertebrate and most bony fish

Ureotelic excretion

Mammals, most amphibians, sharks and rays

Uricotelic excretion

Birds and insects

Guanotelic excretion

Spiders and scorpions

Processes in the excretory system

• Filtration

• Secretion

• Reabsorption

What process occurs in Malpighian tubules?

Active transport

Characteristics of standard metabolic rate

• Resting

• Post-absorbative

• Non-reproductive

• Known temperature

Characteristics of basal metabolic rate

• Resting

• Post-absorbative

• Non-reproductive

• Thermoneutral temperature

Large effects affecting metabolic rate

• Physical activity

• Environmental temperature

Small effects affecting metabolic rate

• Digestion

• Body size

• Age

Rubner’s surface area law

• Large animals have a lower SA:V ratio

• Proportionally less heat loss

How do endotherms receive body heat?

Metabolism

How do ectotherms receive body heat?

The sun

Homeotherm

Body temperature is stable

Heterotherm

Body temperature fluctuates

What is conduction?

Transfer of heat through direct physical contact

What is convection?

Transfer of heat through a moving medium

What is evaporation?

Transfer of heat away from a surface when a liquid changes to gas

What is radiation?

Movement of energy as electromagnetic waves

How does posture prevent heat loss?

• Reduces surface area

• Reduces air/skin interface

• Keeps body heat together

What process prevents heat loss in endotherms?

Vasoconstriction

What process prevents heat loss in ectotherms?

Vasoconstriction

What is countercurrent exchange?

• Arteries and veins carry blood in opposite directions

• This heats up blood in veins

What does TSH do in the body?

Increase heat production and nutrient requirement

What does brown adipose tissue do?

• Increases rate of lipid oxidation

• Lipid catabolic energy is released as heat

How does posture increase heat loss?

• Minimise conductive gain

• Increase air/skin interface

Forms of evaporation to increase heat loss

• Panting

• Sweating

• Saliva

Oxygen cascade

• O2 from the environment

• Into the blood

• To the tissue

• To the mitochondria

Why is air a better respiratory medium than water?

• O2 diffuses faster in air

• More energy is required to move water

Why do gas exchange surfaces have a large SA:V ratio?

To speed up the rate of exchange

Why are gas exchange surfaces very thin?

To keep the diffusion pathway short

Why are gas exchange surfaces partially permeable?

To allow selected materials to diffuse easily

Why are gas exchange surfaces need movement of external/internal mediums?

To maintain a diffusion gradient

How does gas exchange occur in insects?

• External air is delivered to all parts of the body by dividing airways and abdominal pumping

• Spiracles can be closed off to preserve water if needed

How does gas exchange occur in fish?

• Buccal ventilation

• Opercular ventilation

How does gas exchange occur in aquatic animals?

• Gill filament lamella have dense capillary beds

• Water flows over the lamella in the opposite direction to blood flow

How does gas exchange occur in terrestrial animals?

• Air goes down the trachea

• The trachea splits into two bronchi containing alveoli

• Gases dissolve in fluid lining alveoli

How does gas exchange occur in birds?

• Unidirectional ventilation

• Continous O2 delivery

What is stomatal density affected by?

• Temperature

• Humidity

• CO2 concentration

Role of phagocytes

• Engulf and digest cells

• Release cytokines to attract phagocytes

Role of natural killer cells

Kill unhealthy, cancerous or infected body cells

Role of mast cells

Initiates the inflammatory response

Role of complement proteins

• Attract phagocytes to invade microbes

• Activate the inflammatory response

• Lyse invading cells

Process of inflammation

• Blood flow increased

• Phagocytes activated

• Capillary permeability increased

• Complement actuated

• Clotting reaction walls off region

• Regional temperature increased

• Adaptive defenses activated

Immune response in plants

• Closing of stomata

• Production of antimicrobial chemicals

• Strengthening of cell wall

What are MHC proteins?

Proteins on the cell surface expressed on all cells of the body