Plants!
A plant = a multicellular eukaryote that has a cell wall made of cellulose
They develop multicellular embryos
They carry out photosynthesis using chlorophyll
Plants take up water/nutrients in their roots and make food in their leaves
Plants have 2 different kinds of reproductive cells; gametes and spores
Most leaves have thick flattened sections called blades to help collect sunlight
There are 2 main types of roots: taproots and fibrous roots
With a taproot – the primary root grows long and thick (oak/hickory trees and carrots)
Fibrous roots can have extensive branch systems (grasses)
Plants started out in water and had to adapt to living on land
The first plants evolved from an organism much like the multicellular green algae living today
The plant kingdom is divided into 4 groups based on three important
features: water conditioning tissues, seeds, and flowers
Bryophytes have life cycles that depends on water for reproduction – this keeps the these plants relatively small
Peat moss can also be used in gardening
They include mosses, liverworts, and hornworts
Humans can use peat (thick deposits of moss) as fuels
Seedless vascular plants evolved after bryophytes and were the first plants to have vascular tissue
They include club mosses, horsetails, and ferns
Vascular tissues is a transportation system to move water, nutrients, and food through the plant
Xylem helps move water up from the roots
Phloem transports nutrients and food
Seed plants are the most dominant form of plantsThey are divided into 2 groups: gymnosperms (their seed are on the surface of cones) and angiosperms (flowering plants that protect their seeds)
Seeded plants became the dominant plant because they are able to reproduce without water
Angiosperms can be separated into 2 classes: monocots or dicots
They are named for the number of seed leaves (cotyledons) in the plant embryo
Monocots have one seed leaf
Dicots have 2 seed leaves
Other difference between the two include distribution of vascular tissue, stems, roots and leaves and the number of petals per flower
Plants have hormones in order to grow and respond
A hormone = a chemical substance that controls a plant’s pattern of growth and development, and the plant’s response to environmental conditions
Plants have adaptations in order to respond to their environment
Auxins are responsible for phototropism – a plants tendency to grow towards the light
Auxins stimulate cell elongation (the plant getting taller)
Auxins are also responsible for gravitropism – a plants response to the force of gravity
Thigmotropism isn’t caused by auxin but is similar to photo/gravitropism – it is a plants response to being touched
Some plants that are over handled can end up with stunted growth
Cytokinins do several things, including delaying the aging of leaves and helps in the early stages of plant growth
Ethylene helps fruit ripen
Gibberellins produce a dramatic increase in size, particularly in the stem and fruit
Some plants will close their leaves when touched (sensitive plant)
Some plants have sensory cells that allow a quick response (venus fly traps)
Some plant responses don’t involve growth
Many plants have adaptations to the environment they are in
Plants that live in salt water (mangroves) are salt tolerant – they have special adaptations to get rid of the extra salt they take in
Many aquatic plants have tissues with large air-filled spaces through which oxygen can diffuse
Desert plants have extensive roots, reduced leaves, and thick stems so they can store what water they get
Plants that have specialized features for obtaining nutrients include carnivorous plants and parasites
Pitcher plants drown insects in their pitcher-shaped leaves that hold rain water and digestive enzymes
Sundews trap insects with sticky secretions
The Venus fly trap has sensory hairs that when touched tell the plant to snap closed
Mistletoe is a parasitic plant that gets its food from the trees it grows on
Many plants defend themselves against insect attack by manufacturing compounds that can have effects, including death and an interrupted reproduction style, against the animal eating it
Monocot vs. Dicot
Dicot
Monocot vs. Dicot
Dicot
Monocot vs. Dicot
Monocot
Monocot vs. Dicot
Dicot
Monocot vs. Dicot
Dicot
Monocot vs. Dicot
Monocot
Monocot vs. Dicot
Monocot
Monocot vs. Dicot
Dicot
Monocot vs. Dicot
Monocot
Monocot vs. Dicot
Dicot