Cr Biology B Module 4 Lesson 1

Definition of Plants

• Plants are multicellular eukaryotic organisms characterized by cell walls composed of cellulose and the presence of chloroplasts.
• Specialized reproductive organs are present, producing sperm and eggs either on the same or different plants.

Plant Life Cycles

• Unlike animals, many plants reproduce through haploid spores instead of sperm and egg fusion.
• Male and female plant forms can produce gender-specific spores, leading to distinct life stages separate from their genetic origins.
• Plant development occurs through mitosis, allowing new individuals to grow independently from their parents.

Evolutionary Context

• Plants existed for hundreds of millions of years before evolving flowers, lacking structure such as leaves and stems in their earliest forms.
• Traits defining plants include complex life cycles and unique reproductive strategies.

Photosynthesis and Nutrition

• The vast majority of plants (about 99%) photosynthesize, converting sunlight, carbon dioxide, and water into food.
• A small fraction of plant species have lost this ability and have become heterotrophic, engaging in predation (e.g., Venus flytrap).
• The Venus flytrap captures and digests insects using secreted enzymes to absorb nutrients.

Plant Requirements for Survival

• Essential conditions for plant growth include temperatures above freezing, sunlight, and access to carbon dioxide and water.
• Plants require oxygen for cellular respiration and minerals for synthesizing proteins and organic molecules.

Importance of Plants

• Plants are foundational to life on Earth, supporting ecosystems and being vital for the survival of many organisms, including humans.

Definition of Plants

• Plants are multicellular eukaryotic organisms characterized by cell walls composed of cellulose and the presence of chloroplasts.
• Specialized reproductive organs are present, producing sperm and eggs either on the same or different plants.

Plant Life Cycles

• Unlike animals, many plants reproduce through haploid spores instead of sperm and egg fusion.
• Male and female plant forms can produce gender-specific spores, leading to distinct life stages separate from their genetic origins.
• Plant development occurs through mitosis, allowing new individuals to grow independently from their parents.

Evolutionary Context

• Plants existed for hundreds of millions of years before evolving flowers, lacking structure such as leaves and stems in their earliest forms.
• Traits defining plants include complex life cycles and unique reproductive strategies.

Photosynthesis and Nutrition

• The vast majority of plants (about 99%) photosynthesize, converting sunlight, carbon dioxide, and water into food.
• A small fraction of plant species have lost this ability and have become heterotrophic, engaging in predation (e.g., Venus flytrap).
• The Venus flytrap captures and digests insects using secreted enzymes to absorb nutrients.

Plant Requirements for Survival

• Essential conditions for plant growth include temperatures above freezing, sunlight, and access to carbon dioxide and water.
• Plants require oxygen for cellular respiration and minerals for synthesizing proteins and organic molecules.

Importance of Plants

• Plants are foundational to life on Earth, supporting ecosystems and being vital for the survival of many organisms, including humans.