4.3 Continuation of Species Further Questions and Answers

4.3 Continuation of species – Further questions and answers

Q1.

Bk Ch4 S4.3 FQ1

aDecide which of the following types of organisms display internal fertilisation and which show external fertilisation.

frog dog bird snake fish crab spider horse jellyfish butterfly

bStudy the two groups that you have produced in part (a). Describe the relationship between lifestyle and the kind of fertilisation that occurs.

A1.

Bk Ch4 S4.3 FA1

aInternal fertilisation: dog, bird, snake, spider, horse, butterfly.

External fertilisation: frog, fish, crab, jellyfish.

bAll of the animals listed in part (a) that have internal fertilisation are also examples of terrestrial organisms. Those that display external fertilisation are either aquatic or return to the water for fertilisation.

Q2.

Bk Ch4 S4.3 FQ2

Consider the different species of flowering plants listed below. Use an encyclopaedia or field guide to Australian plants to help you group them according to their likely mode of pollination. In each case, give reasons for your choice.

grevillea red-flowering gum silver wattle kangaroo paw saw banksia boronia callistemon waratah snow daisy grass-tree wonga vine mistletoe

A2.

Bk Ch4 S4.3 FA2

Insect-pollinated: boronia, snow daisy.
Bird-pollinated: grevillea, red-flowering gum, silver wattle, kangaroo paw, saw banksia, callistemon, waratah, grass-tree, wonga vine, mistletoe.
Wind-pollinated: not represented.

The flowers of both insect-pollinated and bird-pollinated plants tend to be colourful and scented. In addition bird-pollinated flowers tend to be shaped in such a way as to accommodate the beak of a bird; for example, it may be long and tubular or cup-shaped and contain bird-attracting nectar. Wind-pollinated flowers are generally neither scented nor colourful.

Q3.

Bk Ch4 S4.3 FQ3

Draw a flow chart summarising each of the steps involved in the reproduction of a selected flowering plant, beginning with pollination and ending with the ripe fruit.

A3.

Bk Ch4 S4.3 FA3

1. Pollen grain produced in anther lands on mature stigma.

2. Pollen grain germinates growing pollen tube downwards through style towards the ovary.

3. Pollen tube enters an ovule and a male nucleus fuses with the ovum in fertilisation.

4. Ovule swells as developing embryo grows and endosperm develops as a food reserve in the developing seed.

5. Petals wither and drop off.

6. Ovary swells and elongates to become fruit containing seeds.

7. Fruit ripens when seeds mature.

8. Seed dispersal occurs.

Q4.

Bk Ch4 S4.3 FQ4

aIdentify which of the following are fruits:

gumnut peanut tomato potato strawberry avocado zucchini carrot apple walnut pumpkin rosehip passionfruit grapes

bDescribe the criteria upon which you have made your decision.

A4.

Bk Ch4 S4.3 FA4

aFruits: gumnut, peanut, tomato, strawberry, avocado, zucchini, apple, walnut, pumpkin, rosehip, passionfruit, grapes.

bFruits by definition develop from the ovaries of flowers after fertilisation has occurred. Fruits contain seeds ready for dispersal.

Q5.

Bk Ch4 S4.3 FQ5

Consider the number of offspring that result from a single mating of the following different kinds of organisms: frogs, birds and placental mammals. Now consider the independence of the young, the level of care provided by parents and the chances of survival of the offspring. Outline the trends you notice.

A5.

Bk Ch4 S4.3 FA5

Frogs lay many thousands of eggs at a time, resulting in hundreds of offspring. Young tadpoles are independent, seeking out their own food. In general frogs do not care for their young so the chances of survival decrease as the young become food for other animals. Birds and placental mammals have few young at a time but parental care is an important factor that increases the chances of survival of the young until they can live independently. Organisms that do not care for their young tend to have many offspring at a time; the large number of young increases the chance that a few might survive. Organisms that have only a small number of offspring generally invest a great deal of energy in raising them, thus enhancing their chances of survival.

4.3 Continuation of species FQApage 1 of 2