Animal Reproduction and Diversity Overview

Asexual Reproduction

Offspring arise from a single parent without genetic recombination.

Budding

Offspring grows as an outgrowth of the parent (e.g., Hydra).

Fragmentation & Regeneration

Parent breaks into parts that regenerate into new individuals (e.g., Starfish, Planaria).

Parthenogenesis

Development of an embryo from an unfertilized egg (e.g., some insects, fish, and reptiles).

Sexual Reproduction

Involves the fusion of gametes (sperm and egg), leading to genetic variation.

Hermaphroditism

Individuals have both male and female reproductive organs (e.g., Earthworms, some fish).

Sequential Hermaphroditism

Organisms switch between sexes during their lifetime (e.g., Clownfish).

External Fertilization

Eggs and sperm are released into the environment (e.g., Amphibians, Fish).

Internal Fertilization

Sperm is transferred inside the female's body (e.g., Reptiles, Birds, Mammals).

Reproductive Structures in Animals

Fish & Amphibians: External fertilization is common.

Cartilaginous Fish

Males have claspers for internal fertilization.

Oviparous

Eggs develop externally, nourished by yolk (e.g., Birds, Amphibians, Reptiles).

Ovoviviparous

Eggs develop inside the mother but are nourished by yolk (e.g., Some Sharks, Reptiles).

Viviparous

Embryo develops inside the mother and is nourished directly by her body (e.g., Mammals).

Adaptations for Survival

Different reproductive strategies allow animals to thrive in diverse environments.

Factors influencing reproductive success

Parental investment, Environmental conditions, Predation pressures.