REPRODUCTION

Reproduction Vocabulary

Asexual ReproductionCloneSexual ReproductionGenesEukaryoteMitosisProkaryoteBinary FissionBuddingRegeneration

Reproduction Comparisons

Sexual Reproduction

Asexual Reproduction

Fertilization occurs (combining a male and female sex cell)

No fertilization occurs

Needs two parents Only needs one parent

Occurs in almost all animals and in many plants

Occurs in simple animals and many plants

Offspring are genetically different (diverse) from parents

Offspring are identical copies (clones) of the parent

WHY DO WE NEED SEXUAL REPRODUCTION?

Advantages-Produces genetic diversity (more variety in a species) -One disease may not kill all individuals-Species can change to survive in different environments

x

Pare

nts

Child

ren

Meiosis: Preparing Sex Cells

Meiosis prepares sex cells

• Sex cells must have half the number of chromosomes

• When sex cells combine, the new individual has the correct number of chromosomes

How is the beginning cell different from the cells that

are formed?

MEIOSIS VS. MITOSISMitosis Meiosis

Occurs in eukaryotic cells (Asexual reproduction)

Occurs only in sex cells (for Sexual

Reproduction)

Produces 2 cells Produces 4 cells

Cells have normal number of

chromosomes

Cells have half the number of

chromosomes

Pollination & Fertilization (in plants)

Types of Sexual Reproduction:

Pollination (in Plants)

Sexual Reproduction

Only occurs inside the flowers of plants

Pollen (male cells) are transferred to pistil (female parts) of a different flower

Plants don’t move: pollen is transferred by wind, insects and animals

External Fertilization (in many aquatic animals)

Types of Sexual Reproduction:

External Fertilization (in many aquatic animals)

Sexual Reproduction Occurs inside the water Eggs (female cells) are

released into the water and sperm (male cells) are released near the eggs

Males and females don´t need to touch each other

Internal Fertilization (in most animals)

Types of Sexual Reproduction:

Internal Fertilization

Sexual Reproduction Occurs in most animals Male animals have a

special structure to insert their sperm into the female

An egg (female cell) combines with sperm (male cell)

SEXUAL REPRODUCTION TYPES

Pollination & Fertilization

External Fertilization

Internal Fertilization

Occurs in which organisms?

Plants Aquatic animals Most animals and aquatic mammals

Occurs in which environments?

Land Water Mostly land and some water

Males and females touch/join?

No No Yes

Key Vocabulary Pollen = male sex cellStamen = male flower structurePistil = female flower structure

Sperm = male sex cellEgg/ova = female sex cell

Sperm = male sex cellEgg/ova = female sex cell

Sexual or asexual reproduction?

asexual

WHAT ARE SOME ADVANTAGES OF

ASEXUAL REPRODUCTION?

Advantages-Simple process that can be very quick-Produces many organisms with very little effort-Produces exact copies of organisms which may be perfect for the needed environment (like replacing lost skin cells)

Binary Fission (in prokaryotes)

Types of Asexual Reproduction:

Binary Fission (in prokaryotes)

Asexual Reproduction Occurs in prokaryotes

(simple cells) like bacteria

A cell copies its contents then divides in half

Fast and easy All cells are identical

copies

Mitosis (in eukaryotes)

Types of Asexual Reproduction:

Mitosis(in eukaryotes)

Asexual Reproduction Occurs in eukaryotes (cells

inside plants and animals) A cell copies its contents

(including the nucleus) then divides in half

Fast and easy All cells are identical

copies Helps replace dying and old

cells inside organisms

" Roots or Stemsײ (in plants)

Types of Asexual Reproduction:

Roots or Stems (in plants)

Asexual Reproduction Plants send out roots

or stems to grow up into new individuals

All new individuals are identical copies

Budding (in simple animals)

Types of Asexual Reproduction:

Budding (in simple animals)

Asexual Reproduction New organism (with

identical DNA) grows on top of parent

New organism may separate from parent (like yeast) or may stay attached forever (like coral)

Fragmentation (in simple animals)

Types of Asexual Reproduction:

Fragmentation (in simple animals)

Asexual Reproduction Parent organism

broken into pieces (fragments). Each fragment becomes a new, genetically identical individual

Binary Fission

Mitosis Roots or Stems

Budding

Fragmentation

Occurs in which organisms?

Prokaryotic cells

Eukaryotic cells

plants Simple animals

Simple animals

Occurs in which environments?

Inside prokaryotes (land and water)

inside animals and plants

Land Water and land

Water and land

General process

A cell copies its contents and divides in half

A cell copies its contents (including nucleus) and divides in half

Plants send out roots or stems to grow into new individuals

New organism grows on top of the parent then stays attached or separates

Parent breaks into pieces and each fragment becomes a new individual

ASEXUAL REPRODUCTION TYPES