1. Life Cycles

2. What is a lifecycle?
The different stages an animal or plant goes through during its life.
In plants this includes:
Pollination
Fertilisation
Fruit development
Dispersal of seeds
Germination
What stages might this include?

3. Animal Lifecycles Animal life cycles include: Birth Growth
Reproduction
Death
There are many types of species of animals on the planet.
Fish
Amphibians
Reptiles
Birds
Mammals
Invertebrates (eg Insects)

4. Species Groups
These are the groups we will be looking at in more detail today:
Mammals
Reptiles
Amphibians
Insects

5. Mammals Reproduce through sexual reproduction
Most mammals have very similar life cycles, with the individuals going through similar stages of development:
Females give birth to live young
Young looks like a miniature version of the adult
Female provides milk for the young to grow and develop
Adults take care of the young
Reproduce through sexual reproduction
involving sperm and egg.

6. Lifecycle of a Mammal-Humans

7. Lifecycle of a Mammal-Lion

8. Reptiles
Most reptiles lay eggs
Young looks like a miniature version of the adult
Generally, no parental care is given – the eggs/young are left to look after themselves
Most reptiles reproduce
through internal sexual
reproduction, involving
sperm and eggs

9. Lifecycle of a Crocodile

10. Amphibians Most amphibians lay eggs
After hatching, amphibians usually go through a very different physical form (tadpole) before looking like an adult
Tadpoles and young frogs are not usually given any parental care
Most amphibians reproduce through external sexual reproduction, involving sperm and eggs

11. Lifecycle of a Frog

12. Insects There are two different types of insect life cycle:
Incomplete metamorphosis
Complete metamorphosis.
Metamorphosis means a change of form. This means that the young look very different from the adult.

13. Incomplete Metamorphosis
This is shown by the less highly developed insects. The life cycle shows only three stages:-
EGG
NYMPH- resembles a miniature adult but is not able to reproduce
ADULT
This life cycle has the disadvantage that both nymph and adult often share the same food source. Therefore they can be in direct competition with one another for food. The advantage is that the vulnerable pupal phase is avoided.
Examples include dragonflies, grasshoppers, earwigs and cockroaches.

14. Lifecycle of a Grasshopper

15. Complete Metamorphosis
This is shown by the more highly developed insects. The life cycle shows four stages:
EGG
LARVA- or caterpillar is the growth phase
PUPA- or chrysalis is a stage of internal reorganisation
ADULT
Usually the larva and adult use different food sources. Therefore they are not in direct competition.
This is a distinct advantage as more
individuals of the species can be fed.
Examples include butterflies, moths, bees, wasps, true flies and many other insects, including beetles:-

16. Lifecycle of the Monarch Butterfly

17. Amazing Lifecycles
Some baby spiders (spiderlings) eat the mother spiders as they grow up.
Some female spiders eat the male after mating.
Some parasitic wasps lay their eggs in the head of ants. When the eggs hatch the baby wasps eats the ants from the inside out.
Black lace-weaver cannibalise their mother
Eucharitid wasps are parasitic
Black widow devours her mate

18. Amazing Lifecycles- Kangaroo
Kangaroos have very tiny babies called joeys.
The joey is born at a very immature stage and is only about 2cm long.
After their birth they crawl into the mother’s pouch where they feed and grow and continue to develop.
These mammals are called marsupials.
Examples of other
marsupials are koalas,
wombats, opossums
the Tasmanian devils

19. Life spans
A life span begins with an animal’s birth and ends with its death.
Animal
Life span
Vampire bat
14 years
Chimpanzee
44 years
Kangaroo
6 years
Crocodile
70 + years
Dog
20 years
Butterfly
1 month
Grasshopper
1 year
Frog
11 years
Lion
12 years
Owl
60 years
Elephant
Human lifespan can
vary greatly depending
on where a person lives. In the UK a person is expected to live for about 80 years.
Life span of animals in captivity is longer.

20. Task
Write a report on the life cycle of an animal of your choice that you have researched. Complete for homework.
Make sure you include the following:
Name the different stages of it’s lifecycle with a description of each stage.
Information about how the animal reproduces.
Lifespan
2 more interesting facts about your animal.
Pictures and good presentation.
Good spelling and grammar.