Alligators, Crocodiles & Heritable Traits

• Section 2.0–2.2 covers reproduction and how characteristics are passed from one generation to the next.
• Section 2.0–2.1 focuses on variation within species.

Alligators vs. Crocodiles

• These reptiles are the largest in the world and belong to the same family, Crocodilians
• They live in swampy, warm habitats like the Everglades National Park.
• Alligators' teeth are not visible when their mouths are closed, unlike crocodiles.
• Alligators have a broad snout, while crocodiles have a thinner snout.
• Alligators tend to be grayish black, whereas crocodiles have color variations.

Heritable vs. Non-Heritable Characteristics

• Heritable characteristics are passed from generation to generation like eye color
• Non-heritable characteristics are acquired and not passed on, such as learning to play the piano.

Discrete vs. Continuous Variation

• Discrete variation involves distinct characteristics, like having blue eyes or not.
• Continuous variation involves characteristics with a wide range, like height.

Asexual Reproduction

• Section 2.2 discusses Asexual and Sexual Reproduction.
• Reproduction produces new individuals that can be identical or very different.
• Asexual reproduction involves only one parent where all offspring inherit identical characteristics from the parent.

Asexual Reproduction: Types

• Binary Fission: A cell splits into two identical individuals.
• Examples include protists like amoebas and algae.
• Budding: A parent produces a small bud that detaches to form a new, identical individual.
• Spore Production: The parent's cells divide, and each spore develops into a new individual.
• Examples include fungi, green algae, and molds.
• Vegetative Reproduction: Does not involve the formation of a seed
• A cutting from a plant grows roots in water and develops into a new plant.
• Other forms are runners, tubers (potatoes), and bulbs (tulips/daffodils).
• Each new plant is genetically identical to the parent plant.

Sexual Reproduction

• Sexual reproduction involves two individuals, and the offspring will have mixed characteristics from both parents.
• Sexual reproduction can involve specialized gametes (reproductive cells) from a single parent instead of male and female parents.
• Sexual reproduction in animals involves specialized cells called gametes (sex cells).
• Male gametes are sperm cells, and female gametes are egg cells (ova).
• The unity of male and female gametes is fertilization.
• During fertilization, the male and female gametes join, creating a cell known as a zygote.
• The zygote continuously divides in a process called cleavage.
• This division results in a multicellular life form called an embryo.

Sexual Reproduction in Plants

• Plant reproduction involves male and female gametes joining during fertilization to produce a zygote and then an embryo.
• Most plants produce both male and female gametes, but some produce only one or the other.
• Pollen contains the male gametes and is found on the stamen.
• Ovules contain the female gametes and are found in the pistil.
• Pollination occurs when pollen is transferred from the anther of the stamen to the stigma of the pistil.
• Cross-pollination: pollen from one plant transfers to the stigma of another plant by wind, water, or animals.
• Cross-fertilization: a pollen grain forms a long tube that grows down the style into the ovary.
• The gametes unite to produce a zygote, which then develops into an embryo.

Asexual Reproduction: Advantages vs Disadvantages

• Asexual reproduction does not require specialized cells.
• It produces many individuals quickly, advantageous in stable environments.
• Asexual reproduction allows species to thrive by building a large population quickly however, organisms lack the ability to adapt to change.

Sexual Reproduction: Advantages vs Disadvantages

• Sexual reproduction results in lots of species variation which helps species survive if the environment changes
• Sexual reproduction takes a lot of energy, resulting in small populations.

Asexual/Sexual Reproduction: Organisms that partake

• Sponges and most seed-producing plants can reproduce both sexually and asexually.
• Plants can control their population depending on environmental conditions.

Homework

• Check and Reflect pg. 36 Q's 1-4, and 6
• Assess Your Learning pg. 37 Q's 1-8