2C1 Life Cycles in Organisms Flashcards
Understand the life cycles of animals and plants.
What is a life cycle?
The series of changes an organism undergoes from fertilization to death.
Understanding life cycles helps in studying organism development, ecological interactions, and evolutionary adaptations.
Distinguish between a simple life cycle and a complex life cycle.
- Simple life cycle: involves stages without drastic physical, behavioral, or environmental changes.
- Complex life cycle: includes significant morphological, behavioral, or habitat changes between stages.
What are the three main stages of a plant/animal life cycle?
- Fertilised egg (or seed)
- Juvenile
- Adult
Give an example of an organism with a simple life cycle.
A flowering plant, where the stages involve seed, seedling, and mature plant.
What are the four stages of the mammalian life cycle?
- Fertilized egg
- Infant
- Adolescent
- Adult
What distinguishes mammals in their life cycle?
Mammals share traits such as body hair, separate sexes, and feeding young with mammary glands.
Name an example of a marsupial with a unique life cycle.
Kangaroo, where young develop in a pouch after a short gestation period.
List the five main stages of the human life cycle.
- The fertilized egg (0-9 months in utero)
- Infancy (0-3 years old)
- Childhood (3-10 years old)
- Adolescence (10-19 years old)
- Adult (20+ years old)
The human life cycle stages can vary slightly based on cultural definitions of adolescence and adulthood.
What marks adolescence in humans?
- Puberty.
- Significant physical and mental growth.
What are the two main types of insect life cycle patterns?
- Holometabolous metamorphosis.
- Hemimetabolous metamorphosis.
Insects with hemimetabolous metamorphosis often show gradual changes between nymph and adult stages.
Describe holometabolous metamorphosis.
It includes egg, larva, pupa, and adult stages, seen in butterflies.
Describe hemimetabolous metamorphosis.
It involves egg, nymph, and adult stages, without a pupal stage, seen in grasshoppers.
Name the five stages in the life cycle of a fish.
- Egg
- Larva
- Fry
- Juvenile
- Adult
Do fish typically fertilize their eggs internally or externally?
Most fish fertilize their eggs externally.
What are the five main stages in the life cycle of a frog?
- Egg
- Tadpole
- Tadpole with legs
- Froglet
- Adult frog
Frogs undergo metamorphosis from aquatic tadpoles to terrestrial adults, adapting to dual environments.
How do frogs fertilize their eggs?
Through external fertilization during amplexus.
List the four major stages in the life cycle of birds.
- Egg
- Hatchling
- Fledgling (chick)
- Adult
What unique behavior do most birds exhibit during incubation?
They incubate their eggs by sitting on them.
What are the three main stages in the life cycle of a flowering plant?
- Seed
- Seedling
- Mature plant
What is double fertilization in flowering plants?
It involves one sperm fertilizing the egg and another uniting with polar nuclei to form endosperm.
Describe the process of seed production in flowering plants.
Seeds develop from fertilized ovules within the flower.
What are angiosperms?
The most complex and evolved forms of plant life are the angiosperms, or the flowering plants.
Angiosperms are also the most common form of plant life on Earth today — there are over 270,000 different species of flowering plants (in contrast, there are only approximately 5,500 species of mammals on Earth).
What are the distinguishing characteristics of angiosperms in their life cycle?
They produce seeds enclosed within fruits derived from carpel tissue.
Angiosperms dominate terrestrial ecosystems due to efficient seed production and varied pollination strategies.
How do the vast majority of insects reproduce?
Sexually.
A very small percentage of insects reproduce asexually, meaning that they encompass both male and female parts, or that they do not need a partner to reproduce. However, most insects reproduce sexually, meaning a male and female are needed to reproduce.
In terms of mates, explain how birds are unique to the animal kingdom.
Most birds are monogamous, meaning that they have only one sexual mate during any given mating period.
Some will only have one mate through their entire life cycle.