fewer eggs, high parental care high parental care.
less venerable, to the cold and predators. Eggs are kept inside the body (thin shell) and
Develops in the mothers body (placenta) Any behaviour that improves the survival and future reproduction of an offspring
are laid and hatched when ready
VIVIPAROUS OVOVIVIPAROUS PARENTAL CARE:
R- strategy: many eggs, decreased parental care (fish, frogs). -
i
f
Lays eggs. Develop outside of the body . ' decreases chance of survival.
OVIVIPAROUS -
Increased parental care. - protection and incubation. TYPES OF REPRODUCTION K-strategy: less eggs, increased parental care (birds, mammals) -
Egg with more yolk. More development. increased chance of survival. Parents have ‘built-in’ (innate) drive to
it
care for their young.
FERTILIZATION
VERTEBRATE
- i Mammals
-
Frogs & fish
EXTERNAL INTERNAL
occurs outside of the body. Occurs inside the body.
(Mainly in water)
REPRODUCTION-
Production of a new generation from an old one.
- wasteful, high amount of -not as wasteful, less
sperm and egg needed to sperm and eggs are
ensure fertilisation. needed.
reproductive effort: maximum number of surviving
-No shell, eggs are venerable. -shell is produced.
offsprings, by the minimum amount of effort. Vertebrates goal.
/
-Small amount of yolk present. - More yolk, eggs can further develop
Courtship rituals: behaviour (e.g. dance) LEVELS OF DEVELOPMENT
that attracts opposite sex for fertilisation
THE AMNIOTIC EGG ' '
ALTRICIAL
chorion Shell PRECOCIAL -The young is born weak and helpless &
-gas exchange -The young are born almost fully developed
Allantois they are not well developed.
-forms the placenta acts as a reservoir for waste. and have a good chance of surviving.
embryo -They are: naked, can’t walk/fly, born
(Mammals) -They are: mobile, can open their eyes, have
with closed eyes, rely on parents.
hair, they are not confined to a nest.
-e.g. dogs, birds, kangaroos, humans
-e.g. buck, ducks, horses, ostrich, elephant,
-How they maximise reproduction- high
Amnion penguins, chickens.
Surrounds and parental care, they reach reproductive
-How they maximise reproduction - babies
Yolk sac age because they are fed nutritious food
protects the embryo find food and eat on their own. They protect
Nutrient filled food for embryo
From dehydration and and are protected from predators.
themselves . Therefore increasing chance of
injury survival til reproductive age.
, EXO-CRINE = USE OF DUCTS, TARGET ORGAN = CELLS AFFECTED BY HORMONES HORMONE = ORGANIC CHEMICAL SUBSTANCE ( PROTEIN/ STEROID) HYPER = HIGH
CARRIED IN THE BLOOD STREAM TO THE TARGET ORGAN. HYPO = LOW
ENDOCRINE = WITHOUT DUCTS. (SCATTERED AROUND THE BODY)
Oestrogen: OVARIES -
GONADS HYPOTHALAMUS
- menstrual cycle.
- growth of secondary sex characteristics - ADH (anti-duretic hormone)
- osmoreceptors detect an increase of osmolarity in the blood
Progesterone:
TESTIS and secrete ADH.
- menstrual cycle.
Testosterone: - conserves water (absorbs water in the kidney =
- thickens endometrium for pregnancy
- growth of secondary sex characteristics. more concentrated urine)
ADRENAL GLANDS - sex drive PITUITARY GLAND
.
These glands sit above the kidney. TSH (thyroid stimulating hormone)
- causes the thyroid gland to secrete thyroxin.
FSH (follicle stimulating hormone)
ADRENAL MEDULLA - causes female oogenesis and male spermatogenisis
ADRENAL LH (luitenising hormone)
ENDOCRINE
- adrenaline: prepares the body for action. ‘Flight or Prolactin
- stimulates ovulation - motherly instinct - causes milk in mammary
Flight' hormone. CORTEX ICSH (interstitial-cell-stimulating
The effects of adrenaline: glands.
(Steroid (fat) hormones) Hormone)
- increase in blood glucose levels = more energy. - aldosterone: reabsorption of Na+ GH/STH (growth hormone/
- causes the testis to produce testosterone
SYSTEM
- increased breathing rate, increased depth of breathing, Osmoregularity) somatotrophin hormone)
More oxygen = increased cellular respiration. - cortisol: resists stress, anti-inflammatory and - skeletal + muscular growth
GROWTH DISORDERS:
- increased heart rate - more blood, oxygen and glucose to Anti-allergy. Children:
i
muscles (increased cellular respiration, increased muscle - gigantism: tumor in pituitary gland. Hyper secretion of
activity) GH. Increased skeleton size.
- increased skeletal muscle tone - muscles have quicker - pituitary dwarfism: hypo secretion of GH. Decreased
responses. - blood vessels dilate, more oxygen and glucose Exocrine function: secretes pancreatic juice (digestion) skeleton size. [ treated with GH injections]
i
- increased sweating (to cool down) from pancreatic duct. Adults:
&
- pupils dilate (see more) Endocrine function: insulin and glucagon from islet of - acromegaly: enlarged facial features, hands etc.
- digestive system activity decreases PANCREAS langehans. Thyroxin - main thyroid hormone.
- increased mental awareness. (Glucose is a simple sugar digested from carbs) THYROID GLAND - iodine is needed for production (if iodine is not
- bronchiole tubes dilate. More oxygen available.
- ISLET OF LANGEHANS DISORDERS: present, a goiter may form.
ALPHA CELLS
Children: Function: - increase basal metabolic rate (increase cellular
TYPE TWO: Glucagon - increases blood glucose levels. - cretinism: hypothyroidism - stunted growth, immature respiration)
- forms from an unhealthy lifestyle Negative feedback system: BETA CELLS: sex development, mental retartedness. - promotes normal functioning of the heart and
(Usually starts in adulthood). When blood glucose levels decrease, the alpha cells Adult: nervous system. (Sharpens reflexes and alertness)
Insulin - decreases blood glucose levels
-insulin production is less than is detect the change and secrete glucagon. - myxoedema: hypothyroidism - mental and physical
Negative feedback system: NEGATIVE FEEDBACK SYSTEM:
required or it cannot be used properly. This causes the liver cells to convert stored glycogen to sluggishness, low blood pressure, slow heart, low body -
glucose. After a meal, blood glucose levels rise. Beta cells detect Pituitary glad detects low thyroxin in the blood and
temperature.
this change and secrete insulin. secretes TSH.
DIABETES: Hyperthyroidism - high body temperature, high
Insulin moves to the target organs (muscles and liver) TSH causes the thyroid gland to secrete thyroxin to
TYPE ONE: -cause: autoimmune disease. The immune system attacks B sweating, high heart rate, high blood pressure, muscular tremors
- makes the cell membrane more permeable to normal level.
- starts from birth. cells therefore the pancreas cannot secrete insulin and decrease and nervousness. (Swollen thyroid gland = goitre)
glucose (it absorbs it) high thyroxin = causes the pituitary gland to inhibit
- symptoms: tiredness, frequent urination, blood glucose levels.
- increases rate of conversion from glucose to glycogen the secretion of TSH.
Excessive thirst. - treatment: there is no cure but - insulin injections, regular
(Which is used to store glucose)
exercise and healthy diet.
, CHEMICAL DEFENCES ABSCISIC ACID (ABA)
GIBERELLINS (GA - GIBERELLIC ACID)
AUXINS
FUNCTIONS:
- digestive enzyme inhibitors FUNCTIONS:
1. Elongation of the main stem
- bitter tasting chemicals - most important plant hormone.
1. Growth inhibitor
2. Lateral buds - IAA (indole acetic acid)
- toxins 2. Causes the stomata to close (reduce
- produced in the apical bud and a small amount in the root tip)
- stinging hairs water loss) 3. Stimulates seed germination.
- diffuses downwards.
- essential oils 3. Promotes dormancy in seeds and
- allergy causing chemicals FUNCTIONS:
buds. (If unfavourable conditions)
1. promotes growth: causes cell division and cell elongation.
PLANT
- antibacterial chemicals 4. Abscission of fruit and leaves.
PHYSICAL If the concentration of auxin is too high, cell elongation is inhibited
2. causes apical dominance: the high concentration of auxins at the apical bud
- thorns
- pathogenic
DEFENCES inhibits growth of lateral buds. Lower down the tree, auxins is at a lower
HORMONES
bacteria and fungi concentration and lateral buds produce shoots
- warning colour of If the apical bud is removed, lateral buds will grow. - pruning - plant becomes
thorns bushy.
3. Tropic movements: external stimuli causes altered plant growth by auxins.
/
WEED CONTROL W GROWTH HORMONE Chemicals (which work at at low concentration) which promote growth, flowers,
Spray auxin - kills broad leaf weeds. fruit and shedding of leaves.
i -
Causes very fast growth of weed, which makes them
very weak and causes them to die.
This doesn’t hard narrow leaf plants (they are
Monocot’s) PHOTOTROPISM GEOTROPISM
TROPISM Due to a light stimulus (sun) Due to the gravitational pull
Plants can alter growth to grow in more favourable conditions. -auxin moves away from the light source. Therefore there is a - auxins accumulate on the lower side of the shoot and root. (Gravity)
(Light and water) high concentration of auxin on the shaded side. Shoot: there is more growth on the lower side than the upper side.
Cells elongate towards the light source. Therefore the shoot grows upwards. Curves up.
Root: grows away from the light source. Root: the concentration of auxin on the lower side of the root is
POSITIVELY: plant grows towards the stimulus
too high and growth is inhibited. The upper side elongates downwards.
NEGATIVELY: plant grows away from the stimulus.
IEqs
Therefore the shoot grows downwards. Curves down.
Fa
Seed Root
Fa
-
.
shoot .
Gravity
