biology the human story

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Biology ‐ The Human Story

The Human Story Humans have characteristics that can be used to classify them with other organisms

1. Outline the general classification hierarchy from phylum to species Kingdom, Phylum, class, order, family, genus, species.

2. Define the term species and outline criteria used to identify a species Species‐ a group of organisms that can successfully interbreed in natural conditions to produce fertile offspring

Criteria‐capable of reproduction, natural environment, same number of chromosome, common gene pool, fertile offspring

3. Outline features that classify humans as

Mammal ‐hair, mammary glands, four‐chambered heart Primate‐fingernails and toe‐nails, an opposable thumb, binocular vision, two nipples and a prolonged period of care for young. Hominid‐relatively large brain size and the lack of a tail. Hominin‐bipedal upright gait, arms shorter than legs, and a larger brain size relative to body size. 4. Discuss the uses of the terms hominin and hominid in terms of the arbitrary

nature of classifications systems

The term hominin is used to refer to all human‐like species which is determined by a large brain, S‐shaped spine, bowl‐shaped pelvis, inwardly bent knee and arched foot. The term hominid now refers to orangutans, gorillas, chimpanzees and humans which are defined by genetic structure. These definitions are changing because of the subjective and arbitrary nature of the classification systems.

5. Describe primate characteristics Hand/foot structure and function including opposable thumb or toe

‐Pentadactyl (5 fingers)

‐Nails


‐Opposable thumb

Skull shape and function

‐Enlarged skull for protection

‐Most have a flatter face

Brain size relative to body size

‐large brain

‐visual areas of brain enhanced

‐Cerebral cortex enlarged

Arrangement of the vertebral column to the degree of upright stance

‐Developed from C‐shape to S‐shape spine for humans

‐Foramen magnum has moved downward to allow for bipedal movement for

humans.

Vision, including degree of stereoscopic vision, colour vision

‐forward facing eyes

‐Humans have complete colour vision.

‐Reproductive features including single live young and relatively long gestation

‐Internal reproduction

‐Give birth to live young

‐Mother feeds young

‐Long gestation

‐single offspring

‐Parenting and group bonding

‐high level of parental care

‐social grouping/organisation and bonding

‐hierarchical grouping

Highly flexible learned behavior

‐Long juvenile stage

6. Describe primate characteristics

Primate

Characteristic

Prosimian Old World

Monkey’s

New World

Monkeys

Apes Hominins

Hand/foot

structure

Grasping

hand,

mainly nails

1 digit with

a claw

5‐digits

nails

Opposable

toes and

thumbs

Prehensile

tail

5‐digits

nails

“ “

No tail

Opposable

thumb/toe

5‐digits

nails

Opposable

thumbs

5‐digits

nails

Skull

shape/functio

n

Pointed

face

Wet nose

Nostrils –

pointed

forward

Nose‐

pointed

sideways

Flattened

nose

Bony

flat

forward,

protruding

nose,


(rhinarium)

Acute sense

of smell

(tear drops)

Narrow

nose

partition

Wide nose

partition

eyebrow

ridge

retreating

jaw

Brain: body

ration

large ratio

Large brain Large brain Larger

brain‐

relative to

body size

Complex

thought

Large

cerebrum,

cerebellum

for more

complex

thought

Vertebral

column

Quadraped

al

Quadraped

al

Quadraped

al

Brachiatio

n (

swinging

arms)

Bipedal,s‐

shaped

verterbral

column

Vision Large eyes

Forward

facing but

more on

side

Diurnal Diurnal Rely on

sight

forward

facing eyes

stereo

forward

facing eyes

colour and

stereoscopi

c vision

Reproduction Seasonal

breeding

Callosities

(coloured

behind)

Menstrual

cycle

Parenting Arboreal

small

isolated

groups,

nocturnal

Arboreal

social

groups

Prolonged

periods of

care of

young

“ “ Spend

more time

on ground

Small

social

groups

Complex

social

groups long

gestation

periods

long

infancy

dependenc

y

Examples Lemurs,

tarsiers,

lorises,

bushbabies

Baboons,

macques,

mandrills,

Tamarins,

squirrel

monkeys,

spider

monkey,

capuchins

Gibbons,

orangutan

s, gorillas,

and

chimps

humans


and howler

monkeys

7. Identify data sources, gather, process and analyse information from secondary sources to illustrate the classification process by indentifying features of humans that classifies them as

Animal‐ heterotrophic

Chordate‐dorsal nerve tube

Mammal‐ body hair, mammary glands, four chambered heart, endothermic

Primate‐ opposable thumbs, forward facing eyes for binocular vision, stereoscopic vision, nails, two nipples

Hominid‐ no tail, upright stance

Homo‐ large well‐developed brain, s‐shaped spine, bipedal gait, foramen magnum centered under skull, thinks logically

Homo Sapiens‐ larger brain, social organisaton, high forehead, reduced body hair, protruding chin

8. Similarities and differences between prosimians, monkeys, apes, and humans

Similarities Differences

‐pentadactyl

‐brain: body ratio

‐organised social groups

‐vision

‐single births

‐infant dependency

‐nail

‐upright erect posture

‐unspecialized teeth

‐oppossable thumbs

Pro –monkey‐ape‐hominin

→brain size increases Complexity of social groups Prosimians are nocturnal

Infant dependency for apes and

hominins

Bipedal/quadrapedal

Arboreal‐ground dwelling

Opposable toe‐ hominin doesn’t have

it

9. Analyse information and use available evidence to identify technological advances and resulting new information that have changed scientists opinions about the classification of primates Karyotype analysis → banding pa ern similari es humans closer to chimps

(comparison of chromosomes)

DNA‐DNA hybridization→humans 96% compatible with chimps in similarity of DNA


Haemoglobin→ Chimps more related to humans than gorillas (differ to chimps by 2

amino acids)

(amino acid sequencing)

DNA sequencing → 99% similar human and chimps

( order of bases in gene DNA)

mtDNA→ chimps and humans diverged from a common ancestor 5 million year ago

Fossil and other biological evidence assists in the classification of the relationships between humans and other primates

1. Outline the conditions under which fossils may form ‐quick burial ‐prevention of decay ‐lack of O2

‐ high acidity ‐ low temperatures ‐ low level of moisture ‐organism lies undisturbed (limestone, sandstone, shale) ‐presence of hard body parts ‐compression of rock minerals replace living matter for rock to form

2. Relate the age of the earth to the way in which geological time is described

4.5‐4.5 billion years oldThe geological time scale is put together based on fossil evidence The subdivision of Earth is put into eon, era, period and epoch Many boundaries have developed from extinctions There are five main geological eras: Achaean, Proterozoic, Paleozoic, Mesozoic and Cenozoic

3. Distinguish between and describe some relative and absolute techniques used for dating fossils

Relative Dating‐ dating technique which involves comparing a fossil to something else. Uses the layers of rocks on the strata to determine whether a fossil is older or younger than another. Stratigraphy, a technique of relative dating, involves analysing rock layers of the strata to determine the age of the strata and the age of the fossils relative to its strata. Fluorine analysis, a technique of relative dating, involves determining how much fluorine a fossil has(the more fluorine=older fossil) Absolute dating‐ dating technique which determines and approximate age Dendrochronology, a technique of absolute dating, is the study of seasonal tree rings to determine the age of the tree (more rings=older tree). Radiocarbon dating, a technique of absolute dating, is the analysis of how much carbon‐14 isotope remains in the fossil (less carbon‐14= older fossil).


4. Describe relative dating techniques using fossil record in strata Superposition‐ Analysis of position of fossils in the strata.

Stratigraphic correlation‐ 2 layers of rock are said to correlate if they appear next to

each other meaning the fossils are close in age.

Index fossils‐ If an organism was around at a particular time it could be used as an

index fossil to date other fossils.

‐Fluoride‐Nitrogen relative dating‐ Used to date bones. Over time fluoride

penetrates fossils and nitrogen decreases. The amount of fluoride is measured for a

relative date.

5. Discuss the difficulty of interpreting the past from the fossil record alone

Conflicting dates based upon different technologies Each dating technique has different margins of error

The paucity of the fossil record Fossils are a rare occurrence. There are gaps in the fossil record and the fossil record is heavily weighted towards the organisms that have hard parts such as the shell of the mulluscs. Soft‐bodied animals are not fossilised as often. Fossils tend to be incomplete, this can make it difficult to interpret some features of a fossil or a species. The hardest parts of primate bodies are the teeth and jaw. These are found more often and some species are known from a single specimen of a tooth. Different interpretation of the same evidence Different scientists may specialize in different areas and therefore interpret the evidence differently so there are different interpretations of the same evidence.

6. Evidence for evolutionary relationships in living primates

DNA‐DNA hybridisation‐ DNA strand is heated until it splits into two single strands. One strand is mixed with another strand from a different species, The two strands combine to form a hybrid. Then they are heated to see how much heat is required to break the bonds between the two strands. The higher the heat required the more closely related the two species are. Similarity between humans and chimps is 97.4% Karyotype Analysis‐ examines the shape, size, and number of chromosomes of an organism. Humans have a karyotype (chromosome) number of 46; great apes, gorillas and chimpanzees have a karyotype number of 48. Stained. Humans and chimpanzees have 13 chromosomes with the same banding patterns. Comparison of haemoglobins‐ rabbits are injected with human haemoglobin. The rabbit produces antibodies to the human haemoglobin. These antibodies are extracted and added to the blood of another species. The amount of reaction with the blood of another species can be used toshow how closely related it is to humans. The greater the reaction the more similar is the haemoglobin to human haemoglobin. Eg chimps have a 97 % reaction to humans 100% . The comparison show that chimpanzees and gorillas are more closely related to humans than orangutans. DNA Sequencing‐ compares the order of the four bases‐adenine, thymine, guanine, and cytosine. Chimpanzees share 98% of their genetic code with humans


Mitochondrial DNA as a molecular clock‐ molecular clock made based on the set mutations in a generation

7. Model karyotype analysis

OUTLINE ‐stained chromosomes 1‐4 for 4 living primates (human, chimp, orangutan, gorilla) by colouring in dotted sections ‐cut out chromosome shape ‐in groups based on chromosome number compared number of differences/length of differences of banding patterns between primates ‐recorded differences to determine most closely related RESULTS Overall human and chimp banding patterns were most similar LIMITATIONS ‐only compared 4 chromosomes’ from each primate ‐human error; different interpretations ‐only compared banding patterns; not size, shape, number ‐different measuring techniques making overall comparison difficult

8. Model DNA‐DNA hybridization in order to demonstrate its use in determining relationships between organisms

9. Maternal inheritance of mitochondrial DNA and its importance in tracing human evolution

mtDNA is circular and mutates more often than nuclear DNA, it is also inherited maternally. Mutations of DNA are thought to occur at a regular, measurable rate( Molecular Clock) . The number of mutations accumulates in two species since they shared a common ancestor is the measure of time since they split.Fewer mutations means that the split was more recent.

Debate continues on the relationship between hominid species

1. Examine at least two alternative views on human evolutionary relationships using the same fossil evidence Richard Leakey believes that 2 or 3 species of Australopithecus afarensis were the ancestors of other Australopithecines and later homo’s Johansen on the other hand believes a single species of A. afarensis was the ancestorof all later hominid..

2. Compare the above species, including comparisons of

Body structure

Cranial capacity


Fossil ages and regional locations

Inferred culture

Hominin Group Body Structure Cranial Capacity

Fossil age/location

Culture

Ardipithicusramidus 120cm tall

Possibly bipedal

Ape like body

Unknown Africa, less than 5mya

Possibly forest dweller.

Australopithecus afarensis (Lucy)

152cm/107cm (male/female)

30‐75 Kg

Short, broad, semi‐quadruped, S‐shaped spine, foramen magnum centered under the skull

Small, 375‐500cc

3.9‐3 mya, Northern Ethiopia

Gestures percussive

Limited word communication

Small groups

Non‐tool using

Ground dwellers eating roots, seeds and fruits

Paranthropusrobustus

Heavier body structure than afarensis

125cm

Small, but larger than afarensis,400‐550cc (large and heavy skull) Specialised teeth (small front, large back) for herbivore diet

2‐1.2mya, South Africa

Vegetarian

Tool‐using

ParanthropusBoisei Bipedal movement

Highly covered in hair

Large face

Short legs, long arms

Medium sized, 500‐545cc Sagittal crest

East Africa, 2mya

Highly social

Vegetarian

Interact with physical gestures

Display when it is raining

May have used sticks for digging.

Australopithecus africanus

Bipedal

Similar body size to modern chimpanzees

Small‐medium size, 420‐490 cc Parabolic jaw

3‐2mya, Southern Africa

Vegetarian diet based on seeds, fruit and roots

Lived in groups


Homo habilis Bipedal

About 120cm tall, weighing about 40kg

Sexual dimorphism(males larger than females)

Precise hand grip

Long straight toes and an arched foot enabled them to walk like modern humans

Able to grow bigger due to proteins in meat Medium‐large sized brain,500‐800cc Rounder head than previous species

2.2‐1.6 mya, East Africa

Scavenged and built shelters in groups

Do anything to survive

Inquisitive

Meat eating and also roots and berries

Inventive

‐ool using (stone)

Considered to be first humans

Homo ergaster No opposable toe

Less body hair

Bipedal

White part of eye

Large brain, 850‐900cc (half the size of modern human) Projecting nose

Southern Africa, 1.5 mya

Verbal cues for communication (voice)

Trackers and hunters

Advanced stone tools

Able to walk further due to less body hair and sweat glands allowing heat to escape.

Homo erectus Completely bipedal

Around 150‐160cm tall

Large brain due to meat diet, 900‐1200cc Limited thinking skills Protruding jaw Flat, thick skull with large brow ridge but no chin

Asia, 1.5mya Have fear of giant animals

Work as groups

Discovery of fire

Used axes

May have used language

Lived in caves

Hunter‐gatherer lifestyle

Homo heidelbergensis

Thick bones (heavier than modern humans)

Tall (180cm) specimens known

Quite large, 1100‐1300cc More rounded than earlier species Large nose and large brow ridge Changes at the base of the

0.6‐0.4mya, Europe

Used sophisticated stone tools and wooden spears

Hunter‐gatherer lifestyle

May have


skull are thought to have caused changes in the voice box

lived in constructed shelters

Probably communicated with language.

Homo neanderthalensis

Thick and heavy bones

Heavily muscles and very strong

Short arms and legs, usually 155‐165 cm tall

Compact body enabling them to keep warm during cold temperatures of the ice age.

Very large, 1400‐1750cc (larger than modern humans) Larger skull than modern humans Large eyebrow ridge

0.6‐0.03mya, Europe and Asia

Elaborate stone tools of the Mousterian industry such as scrapers, stone knives and projectile points.

Hunter large animals such as mammoths and bears, indicating social organisation.

Cooked food

Buried their dead in graves

Made clothes and jewellery.

Live in caves and shelters of animal skins.

Homo sapiens Modern body structure

Very large, 1350‐1500cc (smaller than neanderthalensis) Centered foramen magnum Teeth are small and unspecialised

Modern day, entire Earth

Sophisticated culture with many tools and examples of art.

Social structure is complex

Use systems of communication for self‐expression and the exchange of ideas

Demonstrate a desire to understand and influence the world around them, seeking to explain and


3. Outline and examine the evidence of human migration and evolution

6. Evaluate the evidence for two different models of human evolution

The ‘Out of Africa’ model‐ This model states that Homo sapiens arose in Africa 200000 years ago and spread elsewhere replacing archaic populations such as Neanderthals and Homo erectus all over the world. Evidence for this model includes fossil evidence showing that the oldest Homo sapiens came from Africa,transitional fossils have been found in Africa, and also that mitochondrial DNA variation is greatest in Africa(greatest genetic diversity in Africa) and mtEVE has been traced back to Africa. The theory of regional continuity (multi‐regional hypothesis) ‐ This theory proposes that modern Homo sapiens emerged gradually throughout the world and dispersed. Transitional fossils of both H. erectus and H. sapiens found in China, Java, Australia (Peking man, Java man, mungo man)

4. Provide an overview of the similarities and differences of any two species

used in tracing human evolutionary relationships

Features

Homo neanderthalensis Homo sapiens

Chin No chin Prominent chin

Eye brow ridge Large Small

Cranial capacity 1400‐1750cc 1350‐1500cc

Occipital bun Present Absent

Face Mid‐face projection Flattened

Body stature Highly muscled, thick bones Slighter build

Cold adaptations Yes No

Age 200 000‐30 000 years ago 130 000 years ago to present day

Culture Complex culture, burial of the dead, tool making

Complex culture, burial of the dead, tool making

Australopithecus came before Homo. When compared with Australopithecus, Homo have/are: ‐More S‐shaped spine than C‐shaped

manipulate natural phenomena.


‐Taller ‐Shorter, broader pelvis ‐Foramen magnum more centered ‐Jaw more parabolic for speech ‐Teeth more specialised for meat in diet ‐Face more flattened ‐Younger fossil age ‐Jaw less protruding ‐Less prominent brow ridge

5. Asses the contribution of the following on our increased understanding of

human evolution Louis leaky hypothesised that the human species arose in Africa. His wife, Mary, in

1959 found fossil evidence of the species, ‘Australopithecus boisei’ whilst his son

Jonathan in 1961 found fossil evidence of the species ‘Homo habilis’. From these

two pieces of evidence, they hypothesised that the human species’ ancestors arose

in Africa.

Jane Goodall studied chimpanzee in the field and changed the idea that they are

peaceful herbivores when she witnessed at least 5 brutal attacks on lone individuals.

She observed ‘tool making’ by chimpanzees which led to a new definition of

humans. Changed the preconceived idea that culture and tool making was a human

trait.

Johanson‐ discovered ‘lucy’ the transitional link between quadrapedal and bipedals.

How humans have adapted to their environment

1. Outline the mechanisms that led to human diversity

Populations living in distinct environments; naturally selects specific characteristics best suited (isolated by geography)

Sexual reproduction, random mutation in gametes (sex cells), meiosis (cell division) to produce gametes all enabled genes/chromosomes to mix producing different offspring

Migration of populations related in interbreeding further increasing variation

2. Explain the differences between polymorphism and clinal gradation using at

least one appropriate example from human phenotypes

Polymorphism is the presence of two or more distinct forms of a genetically determined character. Polymorphism occurs as selective adaptations to different environments. Clinal gradation is a gradual change in gene frequency in a population as a result of interbreeding. Eye colour and skin colour are both polymorphic. The clinal gradation that


occurs is because of the existence of intermediate environments where different genetic factors have an advantage. Skin Colour‐ The pigment melanin absorbs ultraviolet light. People with dark skin who live in areas of high solar radiation have an advantage over those with paler skin. Melanin prevents the sun’s rays from penetrating to the lower layers of the skin and protects against skin cancer. In areas with low levels of solar radiation, light skin has an advantage because vitamin D production is required for calcium absorption. Lighter skin absorbs more UV radiation which increases vitamin D production. Body Stature‐Tall thin body stature is common in hot tropical areas to allow greater surface to volume ration for heat loss. A stocky short body is found in groups such as Inuits (Eskimos). The stocky body has a smaller SA to VOL ration which allows better heat retention, Sickel‐cell anaemia‐ human genetic disease which produces red blood cells that are folded and have a sickle shape. These cells are less efficient at carrying O2; they block capillaries causing intense pain and death of surrounding cells. People who have this disease rarely live past 10 years. Those who are homozygous for this disease die before they pass the gene but those who carry one gene (heterozygous) for sickle‐cell anaemia have a resistance to malaria. Heterozygous forms have an adaptive advantage in areas where malaria is present.

3. Describe two examples of polymorphism in humans and analyse the

evolutionary significance of the phenotypes displayed

Cultural development has been a significant feature of human evolution

1. Describe the cultural changes that occurred as humans developed into efficient hunters in organized cooperative groups As humans developed into efficient hunters( from individual to organized groups)

they developed verbal and written languages for communication so that they

could work as a group. From close range kill to further distance (safer) using spears

and bow/arrow.Their diet changed from seeds to a varied diet including meats as

well as becoming more complex socially (status rankings). They built permanent

settlements as their complexity with tools improved due to advancements in

hunting ability.

2. Discuss possible impacts of this cultural development Significant cultural changes over the past 40000 years include; more complex

social structure, more complex maternal behavior, change from seed‐eaters to a

varied diet (showing a developed co‐operative behavior within the group), able to

travel longer distances, increased complexity in tools and the development of

permanent settlements. These changes have resulted in:

‐ Industrial and technological revolution→specialisa on of labour and closer

community living


‐Reduced biodiversity‐ As humans develop permanent settlements many species

are harmed and destroyed.

‐Longer life expectancy‐ Due to improved diet, social structure and the

development of medicine.

‐More rapid spread of infectious disease‐ The introduction of transport has

allowed infectious disease to travel across sea.

3. Compare humans and primates

Primate Care of young Length of juvenile period

Social group Tools Communication

Lemur (Prosimian)

Mothers care for young for 5‐6 months

2 years with 2‐5 month gestation

Some lead solitary lives, some have large stable groups, some in fluid associations, and others in small grouping. Most lemurs show female dominance, unique in non‐human primates

No Scent markings and body language include tail waving

Howler monkey (New‐world monkey)

Very little care by mothers but sibling females care for young, males sometimes assist female.

5 years for female, 7 years for male

Live in groups of 1‐2 males and several females with their offspring (up to 16 in a group)

No Very loud vocal signals that can travel to about 10 kilometres.

Baboon (Old world monkey)

Close relationship 5‐6 years with 6 months gestation.

Multi male, multi female

No Vocal signals

Gorilla (Ape) Very close‐ other females may assist

10 years for female, 11‐13 years for male with 8.3 month gestation

Polygynous‐ one male mates with several females

Little Complex vocal signals

Human Very close‐ both parents look after young and other family members usually also help

12 years with 9 month gestation

Family Yes Complex language and complex thought‐ therefore complex toolmaker and user


Current and future trends in biological evolution and cultural development

1. Analyse the possible effects of

Increased population mobility‐ As population increases, so does migration which leads to an increase in diversity and the breaking down of race. As technology increases, transport becomes faster and so does the gene flow between humans which speeds up the breakdown of the concept of race. Increased variation‐increased chance of survival Disadv‐ blood and organ matching more difficult Modern medicine‐ Improvements to modern medicine (vaccinations, birth control etc.) result in greater birth survival rate and overall lifespan. This results in less natural deaths which means that natural selection does not take place – weakest members of population survive ‘weakest genes’ survive in gene pool‐increased aged population‐increased lifespan Vaccine‐decreased death rate and eradicated certain diseases Antibiotics‐overused, increased resistance in bacteria Genetic engineering‐ The manipulation of genes in living organisms which allows for crop cloning and control of genetic diseases. This results in greater global food supply and overall human population. Recombinant DNA technology‐ genetic makeup of an organism can be altered eg insulin made for diabetes Cloning‐clone animals, pest resistant crops Testing for presence of genetic diseases in embryos‐result in elimination of genetic defects Selective breeding techniques‐increased agricultural and individual productivity, better and more varied foods.

2. Account for changes in human population numbers in the last 10,000 years

and discuss the potential impact of modern technologies on future human population

Gene splicing‐ Gene splicing involves cutting the DNA of a gene and replacing some of the DNA. The advantages of this technology include crop development and medical development. The disadvantage of this technology is that it is ethically challenging.This technology has had very little effect on human population growth. Agriculture‐ Agriculture is the production of goods. This technology allows for greater global food supply and increased human population; however land clearance such as deforestation is required for this technology. Agriculture has greatly improved the human population.

3. Outline the purpose of the Human Genome Project and briefly discuss its implications The purpose of the Human Genome Project is to map/sequence all the DNA in each chromosome in the nucleus of a human cell (the human genome). And determine the genetic DNA code of each gene. Gain a better understanding of human disorders Advantages

Compare ‘diseased’ DNA sequences to ‘normal’ DNA seuquences to determine the causes of genetic disorders

Use knowledge to produce possible treatments for genetic disease.

Early detection identification of possible disease


Produce tissue’organs to be clones

Improvement to forensic science

Family inheritance

Evolution (evidence Disadvantages

Higher premium for life insurance

Social ranking, racial intolerance (discrimination) due to knowledge of genetic data

If treatment is unavailable for particular disease knowledge is of no use

Costly

Implications for all family members

Maintaining A Balance Most organisms are active in a limited temperature range

1. Identify the role of enzymes in metabolism, describe their chemical composition and use a simple model to describe their specificity on substrates

Enzymes are protein molecules that catalyse (speed up) chemical reactions. (are a catalyst) . Active sites on enzymes act on substrates and convert them to new products. They remain unchanged and are reusable at the end of the reaction. Enzymes are high specific (lock and key model) 2. Identify the ph as a way of describing the acidity of a substance

The pH of a solution is the measure of concentration of hydrogen ions. Below 7→more acidic Above 7→more basic

3. Explain why the maintenance of a constant internal environment is important for optimal metabolic efficiency If the internal environment does not remain stable, the rate of reactions will decrease.

4. Describe homeostasis as the process by which organisms maintain a relatively stable internal environment Maintaining a relatively stable internal environment in the face of changing condition by regulation cellular processes, organ systems and behavior.

5. Explain that homeostasis consist of two stages


Detecting changes from the stable

Counteracting changed from the stable state

6. Outline the role of the nervous system in detecting and responding to environmental changes

7. Identify the broad range of temperatures over which life is found compared with the narrow limits for individual species Organisms live in a broad range of temperatures

8. Compare responses of named Australian ectothermic and endothermic organisms to changes in the ambient temperature an explain how these responses assist temperature regulation ENDOTHERM‐maintain a constant body temperature regardless of external temperature.Eg Mammals and birds Red Kangaroo‐lick paws so that moisture can evaporate and take heat from the blood vessels‐inactive in shade Mountain Pgymy Possum‐small body, ears coverings , tucks itself in to chest‐ so possums body temp drops to same temp as air which conserves energy Only reproduces in spring Bearded Dragon‐ lies in shade and buries itself in the sand‐ when cold it flattens body and turns a darker shade to absorb radiation Saltwater Crocodile‐mouth stays open to cool down, moves back and forth between hot and cool waters, faces the sun‐reducing heat uptake by the head but warms the body mouth. ECTOTHERM‐have a changing body temperature dependent on external temperature.Eg invertebrates and fish

9. Identify some response of plants to temperature change Groundsel is short → when it snows, it is covered completely. This helps to insulate the plant from the cold. The leaves and stems dessicate (dry out) during winter to reduce risk of damage caused to cells due to water inside freezing. Mulga trees‐ leaves have a thick silvery cuticle to reflect and insulate against heat. Eucalypts hang their leaves down, pointing away from the sun.

10. Perform a first‐hand investigation to test the effect of:

Increased temperature

Change in ph

Change in substrate concentration


11. Develop a model of a feedback mechanism

12. Describe adaptation and responses that have occurred in Australian organisms to assist temperature regulation

Plants and animals transport dissolved nutrients and gases in a fluid medium

1. Identify the forms in which each of the following is carried in mammalian blood

CARBON DIOXIDE

23% carried by haemoglobin as carbaminohaemoglobin

70% as hydrogen carbonate ions (HCo3)

7% as Co2 dissolved in plasma

OXYGEN

98% as oxy‐haemoglobin (HbO2 )

2% as O2 dissolved in plasma

WATER

Solvent of plasma and comprises about 60% of the vol of blood

SALTS

Dissolved in plasma

LIPIDS

As lipoproteins, triglycerides and cholesterol

NITROGENOUS WASTE

As urea, uric acid and creatinine dissolved in plasma

OTHER PRODUCTS OF DIGESTION

Dissolved in the plasma‐ amino acids, sugars, glycerol, nitrogenous bases, hormones and vitamins. 2. Explain the adaptive advantage of haemoglobin

Haemoglobin in a protein found in red blood cells that carries oxygen. Every haemoglobin can pick up 4 O2 molecules Haemoglobin increases the amount of oxygen. Oxygen can reversibly bind with haemoglobin, so that it is easily picked up but also easily released. By being able to carry so much oxygen in blood, mammals are able to effectively maintain homeostaisis.

3. Compare the structure of arteries, capillaries, and veins in relation to their function


ARTERIES‐ carries oxygenated blood away from the heart ‐carries blood under high pressure ‐so thick walls of elastic fibre and muscles are needed. CAPILLARIES‐ smallest blood vessels ‐thin walls‐only 1 cell think VEINS‐carries deoxygenated blood back to heart ‐low pressure ‐thinner walls ‐valves to prevent backflow

4. Describe the main changes in chemical composition of the blood as it moves around the body and identify tissues in which these changes occur

UREA (nitrogenous waste product)‐ The concentration of urea in blood when entering the kidney’s is higher than when leaving it GLUCOSE‐glucose is removed by liver and muscles (aid of hormones) HORMONES‐ produced in endocrine glands and travels in organ in circulatory systems OXYGEN‐concentration is highest in the pulmonary vein, which is taking newly oxygenated blood from the lungs CARBON DIOXIDE‐ highest concentration found in the pulmonary artery.

5. Outline the need for oxygen in living cells and explain why the removal of carbon dioxide from cells is essential

Oxygen is needed by cells for the energy releasing process of respiration. Carbon Dioxide is a waste product from respiration. It must be removed as it can change the ph making it acidic (lowers ph) and interrupt metabolic processes. It decreases enzyme functioning and the capacity for haemoglobin to carry O2.

6. Describe current theories about processes responsible for the movement of materials through plants in xylem and phloem tissue

XYLEM‐WATER‐PASSIVE TRANSPORT Cohesion‐ water molecules attract other water molecules (stick together), so when going up other molecules are pulled up. Adhesion‐sticks to the side of xylem walls (capillarity) Transpiration stream‐after transpiration osmotic pressure in leaf cause water to move in from neighboring cells PHLOEM‐SUGARS‐ACTIVE TRANSPORT MASS FLOW THEORY ‐sugars move in phloem cells by active transport ‐increased sugar concentration makes water in cells les concentrated than surrounding celss


‐water moves from surrounding cells into the phloem cells by osmosis ‐more water increase the pressure in the phloem cells ‐ increased pressure cause substances in the phloem cell to flow to another cells in the phoem tissue and so on, substance gradually move through phloem tissue ‐dissolved substance, especially sugars, are removed from phloem tissue at another loction in the plant so that the flow mechanism can continue

7. Perform a first‐hand investigation to demonstrate the effect of dissolved carbon dioxide on the ph of water

8. Perform a first‐hand investigation to estimate the size of red and white blood cells and draw scaled diagrams of each.

9. Identify current technologies that allow the measurement of oxygen saturation and carbon dioxide concentration in blood and describe and explain the conditions under which these technologies are used

BLOOD GAS ANALYSIS‐ measure O2 and Co 2 content of blood. Small samples of arterial blood are taken, O2 content measured in a cell using platinum and silver electrodes. This produces an electric current, indicating the percentage o oxygen present. Co2 is measured in a separate cell with 2 chambers‐ one for blood sample and one containing hydrogen electrodes. As Co2 diffuses across a membrane, a ph meter takes a reading. The machines are large, used in hospital intensive care units. PULSE OXIMETRE‐Measures the oxygen content of blood and the heart rate. A simple device, where a probe is attached to the patients finger or ear lobe, and two wavelengths of light are passed through to calculate the percentage of oxygen being carried in the body. Used during surgery, recovery after surgery, intensive care units . It is small, easily mover and very efficient. 10. Identify products extracted from donated blood and discuss the uses of

these products

RED BLOOD CELLS‐ used to treat people to increase oxygen carrying capacity, such as trauma, kidney patient and people with anaemia. WHITE BLOOD CELLS‐used to treat people with PLATELETS‐used to treat people with bleeding problems to stop bleeding at wounds. PLASMA‐used to treat people with blood clotting problems after trauma or liver transplants. Plasma is important for burn victims who have lost a lot of blood fluid. 11. Report on the progress in the production of artificial blood and why

research is needed

Blood is in high demand yet short supply. Increasing threat of disease transmission, such as HIV or Hepatitis C. Advantages to PFC’s (perfluorocarbon‐based substitutes) ‐can by fully sterilized, reducing risk of infection


‐ stored at room temperature (easier to carry in ambulances) ‐stored for long periods of time (12 months or more compared to 1 month for real blood) ‐can match with any blood type Disadvantages of PFC based substitutes ‐don’t have other functions of blood eg clotting, immune reactions and nutrient transport ‐problems with getting them to mix with real blood. 12. Perform a first‐hand investigation to draw transverse and longitudinal sections

of phloem and xylem tissue

Plants and animals regulate the concentration of gases, water and waste products of metabolism in cells and in interstitial fluid

1. Explain why the concentration of water in cells should be maintained within the narrow range for optimal function CAUSE‐ water is needed for ‐chemical reaction as a solvent ‐transport of substances (plasma) ‐cooling mechanism ‐diffusion process

EFFECT‐ If water is not regulated cell metabolism will slow down, rate of diffusion will reduce, enzymes could denature, cells could burst or dehydrate resulting in cell death.

2. Explain why the removal of wastes is essential for continued metabolic activity

Wastes products inhibit metabolic processes Urea is a toxin that disrupt cellular metabolism by inhibiting enzymes. Carbon dioxide need to be removed as it lower the ph of blood inhibiting enzyme functioning. 3. Identify the role of the kidney in the excretory system of fish and

mammals

4. Explain why the processes of diffusion and osmosis are inadequate in removing dissolve nitrogenous wastes in some organism Cause‐Diffusion is the movement of substances from high concentration to low concentration. Osmosis is the movement of water across a semi‐permeable membrane. Both processes are passive transport and finish at equilibrium (equal concentration of substances in and out of cell ) Effect‐During reabsorption in the nephron not all good stuff (glucose, water, amino acids etc) will be reabsorbed which could result in these


substances being excreted. Therefore active and passive transport is needed.

5. Distinguish between active and passive transport and relate these to processes occurring in the mammalian kidney.

6. Explain how the processes of filtration and reabsorption in the mammalian nephron regulate body fluid composition Cause‐Filtration occurs between the glomerus and Bowman’s Capsule. It involves the removal of urea and any excess water. Reabsorption of various substances (glucose, amino acids, water, ions) occurs at different locations along the nephron. Effect‐ The process of filtration and reabsorption controls the amount of water and dissolves substances in the blood whilst filtering it of wastes. This is essential for osmoregulation and regulation of body fluid, blood vol and pressure

Perform a first‐hand investigation of the structure of a mammalian kidney by dissection, and identify the regions involved in the excretion of waste products.

biology the human story

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