Plant and Animal Diversity Notes

Plant Diversity

  • Sister taxon of plants:

    • Charophytes: Closely related green algae from which land plants evolved.

  • Plant Structures:

    • Phloem: Transports sugars and organic nutrients throughout the plant.
    • Xylem: Responsible for water transport and mineral nutrients from roots to other parts of the plant.

  • Adaptive Features of Plants:

    • Dependent Embryos: All plants exhibit this trait where embryos develop within the tissues of the female parent.

  • Seed Plant Characteristics:

    • Flowers: Not present in all seed plants. Some seed plants like gymnosperms do not produce flowers.
    • Endosperm: Nutrient-rich tissue found in seeds, but not present in all.

  • Threatened Groups:

    • Cycadophyta: Gymnosperms like cycads are considered one of the most endangered groups of plants.

  • Floral Structures:

    • Anther: Male structure in flowers producing spores (pollen).

  • Plant Evolution:

    • Amborella: Closest known relative of monocots and eudicots, key for understanding angiosperm evolution.

  • Reproductive Structures:

    • Fruit: Mature ovary of a flower that aids in seed dispersal.

  • Moss Lifecycle Limitation:

    • Flagellated sperm requires water to reach archegonia for fertilization.

Fungi and Animal Diversity Overview

  • Fungal Structures:

    • Hyphae: Filaments that collectively form the mycelium, the main growth structure of fungi.
    • Plasmogamy: Fusion of fungal cytoplasm, occurs prior to karyogamy (nuclear fusion).

  • Fungi Classes:

    • Basidiomycota: Group of fungi that produce mushrooms.
    • Chytrids: Fungi known to cause skin infections in amphibians.
    • Mycelium: Structure that maximizes nutrient absorption.

  • Cellular Development:

    • Gastrulation: Process leading to the formation of germ layers (ectoderm, endoderm, mesoderm) from a blastula.
    • Blastula: The early stage of embryonic development consisting of a hollow ball of cells.
    • Protostome Development: In protostomes, the blastopore develops into the mouth.
    • Nervous System Derivation: Contrary to earlier belief, it arises from ectoderm, not mesoderm.

Animal Groups

  • Cellular Functions:

    • Amoebocyte: Versatile cells in sponges capable of differentiating into various cell types.

  • Animal Classification:

    • Anthozoans: Group including corals and sea anemones.
    • Mollusks: Characterized by their foot, which is primarily used for movement.
    • Parasitic Annelids: E.g., Leeches.

  • Crustacea:

    • Not a chelicerate, while shrimp is a chelicerate, insects have an open circulatory system, and earthworms have a closed system.

  • Echinoderms:

    • Not an Echinoderm: Example are lancelets which are chordates, not echinoderms.
    • Insect Groups:
    • Hymenoptera: Includes bees, wasps, and ants.
    • Lepidoptera: Includes butterflies and moths.

  • Metamorphosis Types:

    • Holometabolous: Complete metamorphosis with a pupal stage (e.g., butterflies).
    • Hemimetabolous: Insects develop gradually without undergoing a pupal stage (e.g., grasshoppers).